Fuel mileage efficiency

Mambo42 wrote per post #55;
“Moving weight around I don't really see as a viable option. But your tip is valuable, so that I don't move batteries (heavy weight) into the lazarette. Unfortunately I cannot move it to the bow area, I have no space available there.”

Moving things around is usually the most practical solution to weight imbalance. I worked at Uniflyte in Bellingham Wa. for a time in the engineering dept. and some of my work was to move things around to trim the boat in the roll axis. No stock boat. All were different.

Moving fuel tanks is a good thing to look at if nothing else sticks out. Fuel in the laz should be used last as to it’s far from CG and it varies as fuel is burned. Fuel in the laz is not uncommon. NT32’s come to mind. Things are where they are for good reasons. Engineers and a NA probably chose where things are in your boat but it was (almost certainly chosen for the average expected boat owner). I had water in Willy’s laz and since we had lots and used little it was almost a fixed weight. Every boat is different.

Unfortunately sometimes you just run out of stuff to move before you get the weight distribution where you want. My boat has a slight list to port for this reason. I just haven't come up with anything more to move yet.

That same problem sometimes leads to sub-optimal placement of variable weights (such as my fuel tanks being too far aft because it's where they fit best in the desired size without blocking engine access). So my boat gets more efficient at slow cruise as we get lighter on fuel (no detectable difference on plane as the lower total weight is offset by becoming more bow-heavy).

@ Hippocampus,


Thanks for your reply and in answer to some of your suggestions here some of my thoughts.

Hippocampus said:

M don’t know how deep your pockets are or how technically sophisticated you are. Given what you say about your program you don’t seem to require trans pacific range but rather 1000-1200nm would be more than enough. So that implies your desire to increase efficiency is driven by expense not range. I don’t know your boat but seems reasonable original specs allowed adequate range but that’s your first order of business.

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Right after I bought the boat I had no clue, to be honest, about the fuel usage of these engines and what the range should be. Sure, the broker gave some info, but most of it is sales talk. Only after I started researching, talking to specialists etc I found out that the engines should do about 7 liters per hour each..................but nobody knew at what speed or rpm setting.

I am not a mechanic, but I used to do all the maintenance on my other boats and cars, am also planning to do most of the maintenance on this boat. The engines are not complicated, but the maintenance I had done now was simply heavy work. The cylinder heads and exhaust manifolds weigh a ton, cannot do it alone. On top of that, I still live in the Caribbean (for now), was not in Greece and wanted to get the work done prior to the summer (when we will take the boat out for 2 months). Luckily I found a very good mechanic, he knows the engines inside out.

1000 - 1200 nm range is what would be good, but if for some reason we only do 700 to 800 nm I will have to change our planned route for seeing all the islands in Greece. As stated in a different post, not all islands have marine diesel fuel available, there are no fuel stations anywhere close to the port. So planning your route correctly is important.

Given for early adapters the expense of rewiring a boat, buying and installing the necessary ancillaries and then the LPF batteries is way overkill imho. The expense of all of this will decrease in time and the technology will improve so any Li based system you put in now will be antiquated in a few years. Early adapters faced this issue with solar, now with EVs and in existing boats with Lithium iron phosphate. For your program with the boat you have would think spending money on a clean bottom, good AGMs and the ancillaries to keep them at 70-100% SOC would give you less headaches and way more bang for your buck. A new build or different boat a different decision matrix. Run your boat at around 70% of hull speed if you want to increase efficiency. Don’t worry-be happy.

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The reason for lithium is also an easy one. I do have solar panels on the boat at this moment, but plan to increase the capacity to about 4 Kwp. That way I can charge the batteries completely in one day and with LiFePO4 I don't need to run the generator at all. I made the calculation of how many Kw we will need during the day, at night, for a whole day, for a couple of days and if I can install about 30 Kw at 24 V I can run all equipment for appr 2,5 days without charging. So even during rainy days I won't need to run the generator. I do find it a pity if you are lying in a beautiful bay, enjoying the views, the smells of the sea, the vegetation etc only to have it destroyed by the humming of a generator and the smell of exhaust gasses.

On top of that the generator will greatly reduce our range, thus making more alterations to the planned route necessary. Even to the point where we won't be able to make it to some islands, because of having to turn around for fuel again.

With the generator running I would need to top up the tanks basically every 1.5 months. Without the generator we can stay out for 3 to 4 months. To me that is a big difference.

About AGM's.
I just replaced all the batteries in March, put 6 x 280 Ah AGM's in there, working fine, had to go home for a month, and when I came back I found out the marina had destroyed all my batteries on board. Not just the AGM's, but also all other batteries. But that is a completely different story.

In other words, I will need new batteries again and LiFePO4 goes better with solar than AGM's, plus it gives me almost 40 % extra capacity. AGM's should not be discharged below 50 %, LiFEPO4 can easily go up to 20 % and charge much more rapidly.

So, that is the back ground on the batteries.

As part of your engine survey they should have given you a chart of fuel burn at different rpm, load, speed. Use that to pick the knee of the curve. If you don’t have that run the boat a ~70% of hull speed for a few days then 60% then 80%. Even using sight gauges should be sufficient to get realistic numbers for mpg (or mpl in your metric mind). Those will be real word numbers so useful in planning. I was fortunate. My survey gave me my numbers and turboboust, oil pressure/temp, coolant temp, alternator output at each rpm. I didn’t use those numbers nor the numbers my engine monitor gave me. I had several long runs shortly after starting to use her and got real world numbers using the sight gauges and gallons required at fill ups. So I know 6.8k is most efficient but days work and comfort best at 7.2k with very little penalty. 6. 8k gives me a range of ~1000nm with adequate reserve. So for my program my 600g is adequate. It’s that calculation you want to think about. What’s your longest expected transit. How much fuel is required at the rpm that’s best for efficiency, comfort and engine health to get that distance and allow sufficient reserve. What’s your existing tankage. Is it adequate. If not that’s where your bucks should go before lithiums.

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Unfortunately surveys don't go that deep in Greece. The surveyor looks at the boat condition, a mechanic judges the condition of the engine by listening to it, they take it out for a spin, see how it handles and that is basically it. No charts with fuel burn etc, nothing, zilch, nada. All I knew was the rough state of the boat, the rest was (and in some cases still is) a complete mystery.

Because it is a mystery I am very happy with all the input you guys are giving. It enables me to create a picture of what to expect, what to look for.

My origins in boating don't lie with trawlers, it lies with consoles, speedboats and last one was a 30' cabin cruiser. Here in the Caribbean we use that in the weekend to take it out to a beach, where we will BBQ, drink wine, enjoy and at the end of the day we go home again. That is basically it.

This Defever is going to be a big change in our life. We will be living 6 to 7 months of the year on board, hopping from island to island and that means every little island there is in Greece.

The boat holds 3200 liters of fuel, which is about 850 USG. Based on what I have heard and found so far we should have a max range of about 1200 nm with a 100 gallon reserve. But that is without generator.

With generator the range drops in half and that is going to affect the route we are planning along the islands of Greece, especially in the Aegian sea.

Now, if the numbers are even further off by going at the wrong speed (thus reducing fuel efficiency) or wrong rpm then we will need to revise the plan even more. Perhaps we will have to revise it in such a way that we need to take one or two extra years to visit the islands. Might be possible.

Nomad Willy said:

Mambo42 wrote per post #55;

Moving fuel tanks is a good thing to look at if nothing else sticks out. Fuel in the laz should be used last as to it’s far from CG and it varies as fuel is burned. Fuel in the laz is not uncommon. NT32’s come to mind. Things are where they are for good reasons. Engineers and a NA probably chose where things are in your boat but it was (almost certainly chosen for the average expected boat owner). I had water in Willy’s laz and since we had lots and used little it was almost a fixed weight. Every boat is different.

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Would love to be able to move weight, but you haven't seen the inside of my boat yet.
This boat is 43 years old and every owner has been adding stuff, taking nothing out. They have even sacrificed storage space to get additional equipment in . I must admit that all the extra equipment was one of the selling points for me, but it makes changing things a bit difficult.

Any sight tubes or dip stick?
Easiest way and what we did was with electrical ties on sight tube.
Mark fuel level - add 1000 litres
Go out and use it at most efficient hull speed - the one that puts out hear zero wash or desired cruise speed until back to electrical tie
Note hours
Maths.

Simi 60 said:

Any sight tubes or dip stick?
Easiest way and what we did was with electrical ties on sight tube.
Mark fuel level - add 1000 litres
Go out and use it at most efficient hull speed - the one that puts out hear zero wash or desired cruise speed until back to electrical tie
Note hours
Maths.

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@ Simi 60


Nope, no side sticks. Can't even see the fuel with a flashlight through the side of the tanks, they have discolored into dark pvc. There are markings on the side of the tanks, but you can't see the fuel, so the markings are pretty useless.

And the fuel level indicators have become unreliable. Filled up both rear tanks to the top, one indicated 650 liters, the other 450 liters and it should have been 800 liters each, because that is the real capacity of each tank. I guess I will have to change all the sensors.

IF you know the total volume of your tank(s) and you have sight glasses on each of your tanks, you can determine gallons/inch. Put some blue tape along side of the sight glass and every inch write on the blue tape the number of gallons. All is assuming you have a retangular or square tank. If you have a tank with a curvature the hull, you can start with a totally empty tank, add 50 gallons to the tank, note on the blue tape. Repeat as necessary, always noting it on the blue tape. In either case, you will the most accurate measurement of fuel onboard. The sight glass does not go to the bottom of the tank but by determining the volume it needed to reach the lower sight glass. For the top of the fuel tank takes a bit more caution and bravery, perhaps adding fuel from a gerry can and a hand pump, until first drop comes out the vent. Sop that up with absorbent pad.

Now, I use a rule of thumb. Use 2/3s of the volume then start hunting up a place to refuel. Is you use 3/4 of the volume, start sweating. You may have to transfer all the remaining fuel to one tank, changing the return to that tank too.

Of course if you had planned your refueling points properly and read the blue tape, you should should be in pretty good shape.

OldDan1943 said:

IF you know the total volume of your tank(s) and you have sight glasses on each of your tanks, you can determine gallons/inch. Put some blue tape along side of the sight glass and every inch write on the blue tape the number of gallons. All is assuming you have a retangular or square tank. If you have a tank with a curvature the hull, you can start with a totally empty tank, add 50 gallons to the tank, note on the blue tape. Repeat as necessary, always noting it on the blue tape. In either case, you will the most accurate measurement of fuel onboard. The sight glass does not go to the bottom of the tank but by determining the volume it needed to reach the lower sight glass. For the top of the fuel tank takes a bit more caution and bravery, perhaps adding fuel from a gerry can and a hand pump, until first drop comes out the vent. Sop that up with absorbent pad.

Now, I use a rule of thumb. Use 2/3s of the volume then start hunting up a place to refuel. Is you use 3/4 of the volume, start sweating. You may have to transfer all the remaining fuel to one tank, changing the return to that tank too.

Of course if you had planned your refueling points properly and read the blue tape, you should should be in pretty good shape.

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@ OldDan


Thanks for the tips, but unfortunately will not be possible.



Originally this boat came with metal tanks, but some previous owner (boat is 43 years old) changed to the current tanks. Must have been a massive undertaking, because both engines have to be taken out in order to do that.

The tanks were once white plastic / PVC tanks (that type of matrial), but they did not install any sight glasses. Guess they did not want to run the chance of a breakage and subsequent leak, but that is my guess.

In the beginning it must have been possible to see the fuel through the hull of the tank, because they did mark the tanks quite precisely. That is also how I know how much fuel should be in each tank. Total gets to 2800 liters for all 4 tanks, plus another 400 in the lazarette.

I guess that the last owner before me installed these level indicators in the tank, but have no clue what brand they are (perhaps cheap Chinese ). Is possible that because of the quality or because of the fact that the boat was lying with almost empty tanks for close to a year that the sensors don't work anymore. They are very eratic in their indications. Sometimes you see the indications change right before your eye and the boat does not move at all ! Simply lying quiet in the marina, but the level indications change , not by a couple of liters, but by hundreds of liters !

So I know I need to address it, but did not have the time for that yet. May actually be next year that I can get to it.



In May, after the engines were serviced, we had to take the boat out for almost 3 weeks for multiple reasons.

In order to do that I added 1000 liters to the existing fuel amount and calculated that it would give me roughly 71 hours of engine operation (calculated at 14 liters per hour for both engines). So as long as I would remain below the 71 hours I would not run out of fuel.

I know it is not the correct way to take your boat out, but I had to come up with a way to get the obligations done and still be safe on the fuel side.



The 14 liters per hour or 3.6 GPH was a number I found a couple of times on the internet. No idea whether that was correct, but since we were mostly busy with docking practice, MOB, anchoring practice etc I figured it would be a decent figure to use.



In August / September and part of October we will take the boat out for a much longer period. I will fill up the tanks completely, so to the max of 3200 ltr or 850 USG, but then the calculation will start in a serious manner.
We will travel about 20 - 25 nm each day, have the generator on for a couple of hours and for all of that I have to make my fuel calculation. Because also in those months we will be going to islands where there is no fuel available for boats. In other words, I have to be as accurate as I can be with trying to figure out what this boat uses and how I can drive the boat at optimum speed/fuel usage.



Question is of course: 'why don't I repair the tank sensors now ?'
At the moment am back in the Caribbean and I have contacted many electricians on the island of Corfu. Not a single one has time during the summer, they are all busy working for the charter companies. First available slot is end of October.



But again, thanks for thinking along. In itself your idea would be a great solution.

It is not PVC. It is tygon tubing. An internet search will direct you to many suppliers.
Of course, you could go glass tubing but you will need to build a cage, for each sight glass, to protect the glass tubing.

Ah your question was about tank material. I was discussing sight glass material. Sorry about that.

OldDan1943 said:

It is not PVC. It is tygon tubing. An internet search will direct you to many suppliers.
Of course, you could go glass tubing but you will need to build a cage, for each sight glass, to protect the glass tubing.

Ah your question was about tank material. I was discussing sight glass material. Sorry about that.

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mabo42, does the readout have a name other than, "That SOB is never correct"?

On the topic of efficiency, think about thermo-efficiency? What temp thermostat is everyone using? I noticed a nice brown haze coming up the eastern shore and my temperature gauge reading only around 160. Swapped out to a 180 degree thermostat and the haze has gone away. Considering going to a 195 degree thermostat since the engine manual says 195 is the optimum operating temperature, hope to increase the efficiency of the fuel burn.

Pelican1987 said:

On the topic of efficiency, think about thermo-efficiency? What temp thermostat is everyone using? I noticed a nice brown haze coming up the eastern shore and my temperature gauge reading only around 160. Swapped out to a 180 degree thermostat and the haze has gone away. Considering going to a 195 degree thermostat since the engine manual says 195 is the optimum operating temperature, hope to increase the efficiency of the fuel burn.

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In general, warmer running engines are more efficient. But every engine design has a limit of how warm it can run without risking durability issues, especially under heavy load.

Keep in mind, rated thermostat temperature is when it starts to open. It's fully open 15-20 degrees hotter. So a 180 thermostat can get as high as 195-200 under heavy load when in warm water (pushing the limit of heat exchanger capacity) before it would be considered abnormal.

Pelican1987 said:

On the topic of efficiency, think about thermo-efficiency? What temp thermostat is everyone using? I noticed a nice brown haze coming up the eastern shore and my temperature gauge reading only around 160. Swapped out to a 180 degree thermostat and the haze has gone away. Considering going to a 195 degree thermostat since the engine manual says 195 is the optimum operating temperature, hope to increase the efficiency of the fuel burn.

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What does the manual say about operating in warm waters such as found in the southern areas?? (I really dont know.) Perhaps we should carry a couple thermostats to be swapped out depending upon the injection water temp?

The mid 20% to the very low 30% load seems to be the ideal, fuel efficient zone.

We have had many many message discussing fuel consumption, the engine temp and ER temp as if one has no effect on the others. Each has an effect on the over all efficiency and life of the engine. We cannot separate the effects of a combination.

(I really wish I knew what I was talking about. It just seem a matter of common sense. The three variables discussed are not the only variables that have an effect on the life of the engine and fuel consumption)

The Ford Lehman manual doesn't say anything about operating in warmer or lower seawater temperatures. Provided your heat exchanger, raw water pump, and seawater strainer are working correctly, you shouldn't see a difference because the thermostat is regulating the engine temperature at 160, 180, or 195. Take out the thermostat and you would see a difference because the temperature wouldn't be regulated, engine temperature might be 130 in New England and 140 in the Bahamas.

Pelican1987 said:

On the topic of efficiency, think about thermo-efficiency? What temp thermostat is everyone using? I noticed a nice brown haze coming up the eastern shore and my temperature gauge reading only around 160. Swapped out to a 180 degree thermostat and the haze has gone away. Considering going to a 195 degree thermostat since the engine manual says 195 is the optimum operating temperature, hope to increase the efficiency of the fuel burn.

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I have a 172 degree thermostat. That is what apparently belongs in these engines (according to the company in the Netherlands). I actually wanted to have a 163 degree one, because of the hot water in Greece, but they did not have it available. They told me 172 is the standard thermostat for Ford Lehman 120 Hp.

What they did do to the thermostats however was interesting. They drilled a 3 mm hole in each one. According to them this makes sure the thermostat never gets blocked and that you won't run into trouble later. When I thought about I concluded it was actually a very clever idea.

OldDan1943 said:

What does the manual say about operating in warm waters such as found in the southern areas?? (I really dont know.) Perhaps we should carry a couple thermostats to be swapped out depending upon the injection water temp?

The mid 20% to the very low 30% load seems to be the ideal, fuel efficient zone.

We have had many many message discussing fuel consumption, the engine temp and ER temp as if one has no effect on the others. Each has an effect on the over all efficiency and life of the engine. We cannot separate the effects of a combination.

(I really wish I knew what I was talking about. It just seem a matter of common sense. The three variables discussed are not the only variables that have an effect on the life of the engine and fuel consumption)

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I discussed this subject with the company that did the overhaul of the coolers. According to them it won't make that much of a difference. For the Ford Lehman 120 Hp the standard thermostat is 172 degrees. When I suggested to use a 162 degree because of the warmer water temperature they told me that they did not have that thermostat (it does exist though), but also that it would only matter for a short period of time. Initially the engine would stay cooler, but if you would run the engine for a longer period of time the thermostat would be open all the time and the temperature in the engine would adjust itself to the cooling power of the warmer sea water. In winter time, with lower water temperatures, the thermostat would regulate the engine temp to also get to that same temp.



Only with real hot water (they did not specify how warm that exactly then will be) you could run into trouble of overheating the engine, but their solution was then to run the engine at a lower rpm setting. Lower rpm brings less heat into the block, requiring less cooling.



When I thought about it I concluded it does makes sense, but if anyone can shoot holes in it, I will be all ears.

Pelican1987 said:

The Ford Lehman manual doesn't say anything about operating in warmer or lower seawater temperatures. Provided your heat exchanger, raw water pump, and seawater strainer are working correctly, you shouldn't see a difference because the thermostat is regulating the engine temperature at 160, 180, or 195. Take out the thermostat and you would see a difference because the temperature wouldn't be regulated, engine temperature might be 130 in New England and 140 in the Bahamas.

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I always learned that taking out the thermostat is a real bad idea, since you will start cooling the engine already when it is still cold. On top of that you will have unequal cooling, meaning the first cylinders will be cold, the last one will be warm, creating stress in the block.



After the engine servicing I have done they are now running perfect at a constant 78 degrees Celsius, but that was in May with a water temp of roughly 19 degrees Celsius, which is about 66 Fahrenheit. In August / September water temp will be up at about 90 degrees, so am curious what the engine temp will be then.

M- lived on my boat for most of a decade in the Caribbean. Don’t know about Greece but do know the logistics of getting stuff, especially batteries, is problematic in the windwards.. I wanted to swap out lifelines for Li but couldn’t find a boat electrician I trusted enough to help spec’ing the system and helping with the installation. Then decided to flip to firefly but although I felt confident to DYI between import and shipping and hassles with brokers decided to just replace the flooded Pb the boat came with from China with the lifelines. We ran the genset once a month to exercise it. For those occasions had to scramble to find enough loads. (AC, vacuum the boat, make water, charge power tools etc.) We had 1020 of lifelines, two solar panels, two D400 wind generators. But the trick is low usage. Watermaker was a Spectra Cape Horn Extreme a DC unit. Rare AC usage with good natural ventilation and shade coverings. Propane cooking. All LED lights. Etc.
If your Li batteries (or more likely the ancillaries) fail in remote places you’ll be out of luck. If you can’t figure it out finding a tech locally who can maybe difficult. For a cruiser KISS (keep it simple stupid). You want low tech systems easily understood and diagnosed. You want systems in common usage where parts and service are available.
Would note the following
Rapid acceptance rate of Li is meaningless to most cruisers. Your solar and wind are low (but constant) producers . They won’t exceed the acceptance rate of Pb or carbon.
We kept our batteries at 80-100% most of the time and never went below 70%. After 8 years load testing showed the lowest (engine start) to be at 87%.
For a displacement hull or even SD weight saving isn’t that big a deal. In fact have acquaintances who went Li and then needed to glass in Pb to restore trim.
You will not recover expense at time of sale. The technology will have moved on and it will be antiquated.
In your shoes (and I was in similar) I would add sufficient batteries and alt energy charging so that their service life was excellent and usage was unrestricted. My preference would be carbon fireflies which insurance companies have no issues with and don’t require a massive rewiring. If not readily available in your new cruising grounds then AGMs( like lifelines which can be equalized).
People here seem to not like wind generators. In the winter in the Caribbean windwards I got more from the wind generators than the solar. Wind is 24/7/365 there. Solar isn’t. In the summers in New England got more from the solar. Fatty had the same experience. Don’t know wind patterns in Greece but if you get reasonable wind (10knots) think your experience will be similar. The D400s are nearly noiseless. Used bowling alley wax on the blades once a year. Otherwise no maintenance. Spent a little time getting blades perfectly balanced so no issues with bearings.
My current boat has a high output AC driven watermaker. Thinking of going back to DC. Then my existing solar is sufficient to run it. My current boat has a SeaKeeper so I’m stuck with generator runs. It’s a Onan. When it dies will replace with a slightly smaller Northernlights. I have a mix of golf cart (for house bank) and AGMs (all starts and both thrusters). Will flip to flyfires as I have a two degree list to the side the house bank is on when they die. So the weight saving and getting down to 20% is meaningful.
Your experience with the AGMs could happen with Li. If it occurred with Li would be a even greater financial hit. We’re mom and pop cruisers. We’ve been in areas where yards are few and far between and the technical support very limited. Sounds like you’re looking at similar. In that case avoid anything that hasn’t gained massive general use or requires sophisticated knowledge. People forget you’re on a power boat. It has a alternator that runs every time you move. It will get you through bulk and probably absorb every time you move. Your alt energy will get you through float to 100% at least once a week if you’re actively cruising. Li is a great technology and will dominate the market. But at present for a cruiser looking at refit the advantages aren’t usually applicable enough to justify the downsides.

Hippocampus said:

M- lived on my boat for most of a decade in the Caribbean. Don’t know about Greece but do know the logistics of getting stuff, especially batteries, is problematic in the windwards.. I wanted to swap out lifelines for Li but couldn’t find a boat electrician I trusted enough to help spec’ing the system and helping with the installation. Then decided to flip to firefly but although I felt confident to DYI between import and shipping and hassles with brokers decided to just replace the flooded Pb the boat came with from China with the lifelines. We ran the genset once a month to exercise it. For those occasions had to scramble to find enough loads. (AC, vacuum the boat, make water, charge power tools etc.) We had 1020 of lifelines, two solar panels, two D400 wind generators.

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Logistics is luckily no problem for me. It is fairly easy to get parts in Greece, takes maximum 2 days. The more expensive stuff I bring with my van from all over Europe. I did change the batteries in March, put in 6 brand new 280 Ah AGM's (which I had bought in the Netherlands) so that I would be able to have enough power during the summer. They were about half the price I would have to pay for them in Greece, so that was an easy decision. Loaded the van up with other parts and tools, then drove to Greece.

Since they were working on the engines they needed to have the boat under power all the time, which meant it was connected to shore power. In Greece all the marina's are changing from post paid to pre paid electricity, but............the max you can put in is 50 euro. For that amount you will get about 60 Kw of electricity. The marina promised me they would put a new card in as soon as the first one was finished, but obviously they completely forgot. Result is that all the batteries were drained completely, so when I came back every single battery on board was dead. That was a 5000 euro damage and the marina stuck up their middle finger.

And this was the second time they destroyed all the batteries, first time was done by one of their employees who decided to switch on the bilge pumps and did not switch them off again. A float switch had failed, so the bilge pump kept running and in the end drained all the batteries. That was the reason why I had to replace the batteries in March to begin with.



So I will need to change everything again and the reason for lithium is the higher discharge they can take. Also, the amount of space required to upgrade lithium to 24 V as compared to AGM to 24 V is almost half. Nowadays you can buy Winston cells and they are much higher than your standard AGM battery. They are also much easier to handle. On top of that, if one cell fails, you simply buy a new cell, not a complete battery.

But the trick is low usage. Watermaker was a Spectra Cape Horn Extreme a DC unit. Rare AC usage with good natural ventilation and shade coverings. Propane cooking. All LED lights. Etc.

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Unless I start exchanging all the equipment on board to 12 or 24 V equipment I have a constant discharge of around 500 W at 220 V, which is around 20 A at 24 V or 40 A at 12 V. The former owner simply installed all 220 V equipment and changing everything is going to cost about 30.000 - 40.000 euro and then I still have the battery capacity problem.

Once I start adding equipment as airco, washing machine, dish washer, TV, stereo, watermaker etc the discharge will go up even further. If I would run 1 airco at night we would have a charge of about 50 Ah (24 V) extra. According to my calculations I will need about 700 Ah at 24 V per night maximum. With only 70 % of the capacity available I need a minimum battery capacity of 1000 Ah at 24 V. At 12 V that would double and with AGM it would triple. And that is where the problem starts, because I have no space to put so many AGM batteries.

If your Li batteries (or more likely the ancillaries) fail in remote places you’ll be out of luck. If you can’t figure it out finding a tech locally who can maybe difficult. For a cruiser KISS (keep it simple stupid). You want low tech systems easily understood and diagnosed. You want systems in common usage where parts and service are available.

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Luckily it is fairly easy to get a hold of a new Winston Cell and they are being sold in Greece / Croatia as well. Victron is from my homecountry, so easy contacts there and since I will be installing the system myself I will be able to do simple maintenance myself. For bigger problems I can always refer to the many reps these companies have in Greece and Croatia. And as stated, spare parts are readily available.

Would note the following
Rapid acceptance rate of Li is meaningless to most cruisers. Your solar and wind are low (but constant) producers . They won’t exceed the acceptance rate of Pb or carbon.
We kept our batteries at 80-100% most of the time and never went below 70%. After 8 years load testing showed the lowest (engine start) to be at 87%.
For a displacement hull or even SD weight saving isn’t that big a deal. In fact have acquaintances who went Li and then needed to glass in Pb to restore trim.
You will not recover expense at time of sale. The technology will have moved on and it will be antiquated.
In your shoes (and I was in similar) I would add sufficient batteries and alt energy charging so that their service life was excellent and usage was unrestricted. My preference would be carbon fireflies which insurance companies have no issues with and don’t require a massive rewiring. If not readily available in your new cruising grounds then AGMs( like lifelines which can be equalized).

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One of the reasons is that I can change over to lithium for a fraction of the cost of what you would pay in the US. I will pay exactly 1/5 of the price they normally cost. The importer of the Winston Cells is located in Czech republic and they have a factory outlet. Since I have a van I can go there, pick them up, export them out of the EU into Montenegro, which means I will get 24 % VAT back again. And in Montenegro they won't charge VAT since the system is going on a boat which is not registered in Montenegro.

If I would have to pay full price I would be looking at a 100.000 euro conversion, now I am looking at about 20.000 euro total (lithiums, new inverters, bms etc plus the solar panels). If I compare that to exchanging all my 220 V equipment on board I basically save 50 %. So that is one added reason for lithiums.
Another reason is that lithiums can handle the higher ER temperatures, AGM's cannot. AGM's function well in 20 degrees Celsius, but if you store them in temps of 40- 50 or even 60 degrees you reduce their lifespan drastically. They could go from a 7 year lifespan to only 2 years.

I agree that I won't be able to recoup the money at all, but that is also not my goal. I got the boat well below market value, so if I keep the boat in good condition by investing in it I will still have spent only market value and the boat being that old is not likely going to drop much lower. I am somewhat older than my wife, who is Mediterranean and once I am dead she can keep the boat in her family for many more years to come. She is also fully licensed, as well are other members of her family. If all goes well the boat won't be on the market for at least 20 or 30 years............as long as the boat is well maintained.

People here seem to not like wind generators. In the winter in the Caribbean windwards I got more from the wind generators than the solar. Wind is 24/7/365 there. Solar isn’t. In the summers in New England got more from the solar. Fatty had the same experience. Don’t know wind patterns in Greece but if you get reasonable wind (10knots) think your experience will be similar. The D400s are nearly noiseless. Used bowling alley wax on the blades once a year. Otherwise no maintenance. Spent a little time getting blades perfectly balanced so no issues with bearings.

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Unfortunately wind is limited in Greece and Croatia. Greece has a bit more wind than Croatia, but most nights and early mornings are dead calm. In the afternoon the wind picks up, but usually that is max 15 kts for about 5 to 6 hours. In wintertime there is more wind, but then we will not be on the boat.



[/QUOTE]My current boat has a high output AC driven watermaker. Thinking of going back to DC. Then my existing solar is sufficient to run it. My current boat has a SeaKeeper so I’m stuck with generator runs. It’s a Onan. When it dies will replace with a slightly smaller Northernlights. I have a mix of golf cart (for house bank) and AGMs (all starts and both thrusters). Will flip to flyfires as I have a two degree list to the side the house bank is on when they die. So the weight saving and getting down to 20% is meaningful.

Your experience with the AGMs could happen with Li. If it occurred with Li would be a even greater financial hit. We’re mom and pop cruisers. We’ve been in areas where yards are few and far between and the technical support very limited. Sounds like you’re looking at similar. In that case avoid anything that hasn’t gained massive general use or requires sophisticated knowledge. People forget you’re on a power boat. It has a alternator that runs every time you move. It will get you through bulk and probably absorb every time you move. Your alt energy will get you through float to 100% at least once a week if you’re actively cruising. Li is a great technology and will dominate the market. But at present for a cruiser looking at refit the advantages aren’t usually applicable enough to justify the downsides.[/QUOTE]
You are right about the risk of having the same happening with Li as what happened with the AGM's.

I think it was a very unfortunate combination of factors, because if the work on the engines would not have been necessary the boat would have been disconnected from shore power and solar would have kept the batteries charged, the whole thing with the AGM's would have never happened.

The marinas changing from post paid to pre paid is going to open up a can of worms for them, since their responsibilities now become much bigger. They don't want to accept it, but when you limit the amount of pre paid electricity someone can buy you know you are going to run into troubles in the long run. It won't take long before they start figuring that one out.



As for us starting from 2023 we will be more or less living on the boat and I already made a decision that no work on the boat will be done anymore without me being present. I don't want situations again where batteries don't get charged, but at the same time equipment is draining them.

Also, I will expand the total solar capacity to 3 - 4.5 Kwp, which will be more than sufficient to keep the batteries charged. In winter time I can then put covers over most of them to reduce the produced Kwp.

Idea is also to haul the boat out every winter, put her on the dry and then she can be plugged in on a trickle charge.

What happened now with the double destruction of all the batteries is most likely not going to happen again...............(famous last words).

Mambo42 wrote;
“I have a 172 degree thermostat that is what apparently belongs in these engines (according to the company in the Netherlands). I actually wanted to have a 163 degree one, because of the hot water in Greece, but they did not have it available. They told me 172 is the standard thermostat for Ford Lehman 120 Hp.”

I had a newer engine the only difference in design that I’m quite sure of is the thin wall casting of the block and head.
I had a 190 thermostat and saw 200 degrees readout much of the time. As long as the engine holds pressure all will be just fine. It was the original thermostat. To some small degree I suppose it upped the chance of a gasket failure but considered it a remote possibility. Mitsubishi apparently thought so too. Used the old school green AF as no aluminum came in contact w the coolant.

Never had a problem.

Sadly now that floscan has disappeared, I was searching recently for a replacement.

I came across this Australian company. Appears to be priced right even with all the shipping etc.

Anyone tried them or has knowledge?

Engine Fuel Consumption Gauge

Heres a video on youtube of scintex..

I wonder the reason for Flow Scan went belly up.
I had one installed on my N46. Pretty neat.

OldDan1943 said:

I wonder the reason for Flow Scan went belly up.
I had one installed on my N46. Pretty neat.

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Total speculation, but here goes....


First, very niche product, and probably not more than one guy in a garage. That usually doesn't outlast the individual's interest and attention. It can last if the product provides a living for the principal, but is less likely to last if it doesn't.


Second, failure to evolve. It's a single instrument (flow gauge), and over the past decade or two stand alone instruments have become pretty uninteresting. If they had evolved it to integrate with N2K or J1939 so it could work as part of a larger system, that would have at least bought them some more runway. But it would have taken time and money to develop, build, and market, so worth it? Who knows.


In early stage tech investing there is a saying that there are features, products, and companies. It takes a company to survive and thrive, and even that isn't a guarantee, as we all know. I think at one time Flow Scan was a product, but then got reduced to being a feature.

I do have a readout on my VesselView. Perhaps he let patents expire, people seized the opportunity to start their business???
Or perhaps licensed others?

OldDan1943 said:

I do have a readout on my VesselView. Perhaps he let patents expire, people seized the opportunity to start their business???
Or perhaps licensed others?

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There's another way it became obsolete - Electronically injected engines tell you how much fuel they are burning via J1939. No extra devices are required.

M= it’s amazing how the logistics and expenses for the same activity vary by location. Thanks for sharing the rationale and rational thinking for your decision. Have had troubles with shore power pedestals. We run 120/60 boat. Throughout the Caribbean access maybe be limited (St.Lucia and the French islands). We’ve been in places where they aren’t grounded or your breakers flip due deteriorated wiring. I’m currently in a big US marina. My slip has no 30amp just 50amp so on a splitter. A t storm comes through and at least one leg goes down. I had my prior boat set up as to NEVER require shore power nor shore water. I’ve learned to not trust anyone except myself. Even when I’m gone and dependent upon yacht management I don’t want them to have to scramble if shore power goes down. Perhaps in your situation it may not be possible to be shore power independent. But will say it was a new world and much lower stress being so. Especially when I wasn’t on the boat for significant periods of time.

Remote monitoring can be a wonderful thing for power issues. Power went out at the whole marina once last year, leaving the boat running on battery/solar. That means no A/C and a few other things, but it was late at night when I noticed the boat was on battery power (remotely from home). Wasn't super hot or humid, so I figured I'd be there the next day anyway, so I could just worry about it then. But if for some reason the batteries had gotten low before then, I would have gotten an alert.

I'm a "Simple is as Simple Does" guy...

Every boat I've ever owned never stays connected to shore power when I'm/we're away from it for more than several hours... or for days, weeks, months.

In that: I simply shut off all breakers on electric control panel, shut off Perko battery breakers [isolating all batteries] and unplug from shore power at both the shore receptacle and on board receptacle. Leaving open screened airflow locations [windows/hatches etc] open-enough to suite the season and climate phase of year.

This makes my boat an "Island" unto itself... sitting in the water with no connection to shore power grid and isolated DC bats so no bleed into/onto boat parts. Great fire safety as well as reduced metal corrosion capabilities.

Mambo42 said:

What they did do to the thermostats however was interesting. They drilled a 3 mm hole in each one. According to them this makes sure the thermostat never gets blocked and that you won't run into trouble later. When I thought about I concluded it was actually a very clever idea.

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If concerned about fuel efficiency, those thermostats should be replaced. I had the same "clever idea" done to mine. Whatever the possible problem the hole is intended to fix, it does create immediate problems.

My little 3 mm hole made the engine warm up really slow. In fact at idle it would not warm up. Even running at 1,500 rpm, it would take awhile to get above 130 degrees. It was a 170 degree thermostat, but only got to that temp after running at about 1,800 rpm, which is above the rpm and below the temp that what I wanted to run at. Cooler isn't better for diesels.

Thermostats for the vintage Ford Lehman are available for about $35 on the internet. Thermostats for the vintage Ford Mustang are available for $9 at the local auto parts store. Same thing. Stant (big brand name) makes one that doesn't block air (the purpose of the 3 mm hole?) but still works properly. I bought a 180 degree one. Running at WOT, the temp will bump above 180 for a minute and then settle back. For $9 each, I bought a spare and tossed the mutilated one.

What is it that would block the entire thermostat poppet valve but not a 3 mm hole?