Hybrid Boats

For the next few decades there is no motive power that is cheaper than a properly sized simple diesel.

For a liveaboard one should concentrate on the systems used to create lifestyle.

Solar for battery topping, SOC 80 to SOC 100 cant be beat.

Propane for cooking and refrigeration , the best solution.Gas HW heater , in northern areas otherwise a good solar system will do fine.

Sun covers , >we prefer yard umbrellas < is one way to live with out air cond.

Inverter for power tools is fine.

IMO if you want to use the least possible fuel for propulsion, sail

Using fuel for transit doesn't bother me, I want to lower the amount of diesel it takes to boondock. I already have access to a 40 ft trawler hull. I would like to refit it it in a way that it would be able to sit at anchor either occupied or unoccupied for extended periods of time without using large amounts of diesel fuel.

I just figured that if a large amount of battery power were needed for extended anchoring it would be worthwhile to ad hybrid electric to the propulsion system.

With out a doubt the best hybrid system is still sail / diesel but this 40 ft trawler is falling into my lap. And one of the reasons it is falling into my lap is that the current owner knows that I am an engineer that is interested in alternative energy.

I would very much like to refit this boat in a way that would make him proud and end up with a practical economical liveaboard cruiser.

I am also interested in ideas that may push the envelope, although they probably won't make it into the refit.

Thanks for your comments..

DiamonDiver said:

I am also interested in ideas that may push the envelope, although they probably won't make it into the refit.

Thanks for your comments..

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RJTrane is a member you should look up posts here for. He has a solar powered catamaran cruising boat and frankly multi-hull is your only real option for the kind of propulsion you dream about.

You can still have an efficient 40' diesel powered boat. Propane for sure and use the solar panels to shade the boat from heat gain and to produce electricity. It's amazing how efficient a boat can be depending upon the toys and creature comforts you can live without. LED lighting and high efficiency appliances help too.

Good luck with your project.

If you are in a warm area , and the hull is nor cored below the WL, a set of DC fans that lift the bilge area air up into the cabin can help the interior stay at water temperature.

This with a proper sun shade (can stand thru a thunderstorm) will be as cool as one can get with out air cond.

Propane reefer , cooking , heat and HW with a couple of panels to keep the batts up will require NO diesel, for a simple lifestyle.

Gravity FW day tank, no DC water pumping load .

Sitting at anchor without using fuel is easy. Don't use HVAC. Don't use a reefer or ice, use oil lamps instead of electric read instead of TV etc. this is how we did it before we discovered we needed all the fancy stuff. My first boat didn't even have a shore power hookup yet spent months at a mooring. Cruising did involve stops for ice and water but the ice wasn't strictly needed.

Solar panels can easily improve the lighting situation but oil lamps provide some warmth I cold weather.

A company called Le Boat ordered 25 50' hybrid boats from Benetau with joystick steering, they broke down so often there was an engineer permanently on the road with a van fixing faults. In the end they disconnected the hybrid and joystick systems and reverted back to diesel conventional wheel steering with bow thruster. They cost 350k and are now for sale at 250k. enough said by that.
Queens university engineering department invented a small turbine that would fit in a large suitcase in the 70's so nothing new there.

A good hull for a hybrid mono hulled boat would be a larger version of the FG steam launch hulls for steamboat builders.

They have a plum stem and fantail stern optimized for very low power. There's a small boat builder near here that makes hulls. About 26' I think. A bigger one would require a one off construction.

If you optimize hull shape, propulsion systems and domestic systems to minimize energy use enough to allow solar/electric or hybrid operation, then you could install a 20hp diesel and save massive bucks. Or just get a sailboat. When it gets to $10/gal, that's how I will travel.

Five or six years ago good friends of ours decided to take their boat to SE Alaska and back. Both retired, they alloted five months to do the trip. Their boat was a 30' Newport sloop. No generator. Yanmar low hp engine. Solar panel to top off the batteries.

Thanks to the fact that in this area the winds and strong titdal currents seldom align to help you get where you're going, in that five month period they were able to sail the boat exactly two times.

The went all sorts of places and exlored and did all sorts of things. For that five month trip up and back from Bellingham, WA, all but a few hours of which were under power, they used exactly 185 gallons of diesel.

They had a small AC/DC refrierator on board, and they made supply and water stops when necessary. But for the most part, they were anchoring out in all the places they visited.

An easily-driven hull with a small propulsion diesel, a handful of batteries, and solar (or wind) for recharging on the days the motor isn't run makes for a pretty "off the grid" setup to my way of thinking.

There's some cool stuff here. An efficient vessel is as much about how you manage you resources as the basic configuration.
With a conservative approach almost any displacement style boat can be operated economically, with a refined configuration a trawler style boat can be inexpensive to operate.

I believe in the long run it is less expensive to spend some money up front and end up with a thrifty boat than try to operate a high HP boat with a non-economical layout cheaply.

Energy management is important to me. Solar, wind, and battery management along with HVAC, refrigeration and potable h2o management all play a part in economical cruising. Properly allocating and not wasting precious resources are also part of the package.

I know that hybrid propulsion has left a bad taste in some posters mouths, but I believe that hybrid is maturing and battery technology as well as efficient diesel motors and battery management is becoming economically viable and reliable. I don't know if we're there yet, but the time is coming soon where hybrid propulsion will be accepted as part of economical cruising.

>but I believe that hybrid is maturing and battery technology as well as efficient diesel motors and battery management is becoming economically viable and reliable.<

It is but it is suitable for a remarkably small number of marine uses.

A constant power need like a propulsion engine , diesel cant be beet.

For wide variations in power , a tug boat , a cruise ship it could be worthwhile , but mostly for commercial users that operate 24/7.

What is needed , is still not available at any price , BETTER BATTERYS!(energy storage)

An explanation of Steyr's parallel hybrid system;

High-Bred Hybrids: Serial Versus Parallel | Boating Magazine

Steyr site;

http://www.steyr-motors.com/marine-...hybrid-propulsion-system-diesel-and-electric/

You know how guys seem to end up drinking and smoking cigars on the upper deck while the girls settle in in the salon. Well an often had conversation is to purchase one of the many older Hatteras and convert it into a trawler by replacing the old tired Detroit’s with smaller lower power non turbo diesels and travel at trawler speed. Install solar and wind power , large battery bank and an inverter. Cheap large boat with new cheep power?

DiamonDiver said:

There's some cool stuff here. An efficient vessel is as much about how you manage you resources as the basic configuration.
With a conservative approach almost any displacement style boat can be operated economically, with a refined configuration a trawler style boat can be inexpensive to operate.

I believe in the long run it is less expensive to spend some money up front and end up with a thrifty boat than try to operate a high HP boat with a non-economical layout cheaply.

Energy management is important to me. Solar, wind, and battery management along with HVAC, refrigeration and potable h2o management all play a part in economical cruising. Properly allocating and not wasting precious resources are also part of the package.

I know that hybrid propulsion has left a bad taste in some posters mouths, but I believe that hybrid is maturing and battery technology as well as efficient diesel motors and battery management is becoming economically viable and reliable. I don't know if we're there yet, but the time is coming soon where hybrid propulsion will be accepted as part of economical cruising.

Click to expand...

DD,

What you would like to accomplish is doable but you will have to think outside the box to pull it off. First and probably must important is hull efficiency combined with minimum wetted surface and lightweight displacement. Since you mentioned the Caribbean as your chosen cruising grounds this will lend itself to you being able to pull it off. Since distance between islands is generally less than 100 nm, a large propulsion battery bank would be needed. Basically you harvest enough energy from solar to both meet domestic needs while on the hook and fill the bank over days for the next passage.

Real estate on a boat for solar panels is limited, so unless you need something that can cross oceans, it is easier to size the panels to charge the large battery bank over a period of 4~5 days for your next passage. Here are two examples of sizing for ocean crossings....

10 kw of solar for and average speed of 5 kt across the Atlantic
transatlantic21: The world's first crossing of the Atlantic on a solar boat

8 kw
Boat - SolarWave

For your needs, 3 kw of solar and around 35 kWhr of LiFePO4 cells in a small cruising cat would give you 25 nm per day or on the hook for 4 days then a 100 nm run.

You mentioned propane for refrigeration which would mean an ammonia based system which is rather inefficient. Your hotel loads are such a small drop in the bucket compared to propulsion loads, just go with an all electric galley and do away with propane.

There are some hulls out there that are particularly easy to push, but in the 40' or so monohull category, not so much. If I were looking at investing in a hybrid system, I'd probably go with a cat. Among the cats are Aspen, Motorcat, maybe a de-masted Fisher, Americat or Endeavour 30. All of these are something that 25 HP can push to some degree. Full-displacement mono-hulls like Legacy 32 may also give some decent performance but less room for solar. Still, like FF pointed out, running the same boats with an economical diesel is some pretty skinny economy, and finding one cheap, that needs re-power, and doesn't need referbed is not impossible, but rare.

If I was going to do it, I can't think of any cheap, 40 ft. mono-hull platform that I'd try it with.

healhustler said:

There are some hulls out there that are particularly easy to push, but in the 40' or so monohull category, not so much. If I were looking at investing in a hybrid system, I'd probably go with a cat. Among the cats are Aspen, Motorcat, maybe a de-masted Fisher, Americat or Endeavour 30. All of these are something that 25 HP can push to some degree. Full-displacement mono-hulls like Legacy 32 may also give some decent performance but less room for solar. Still, like FF pointed out, running the same boats with an economical diesel is some pretty skinny economy, and finding one cheap, that needs re-power, and doesn't need referbed is not impossible, but rare.

If I was going to do it, I can't think of any cheap, 40 ft. mono-hull platform that I'd try it with.

Click to expand...

I agree Larry.

The Motorcat 30 seems to be one of the most efficient hulls, able to run 25 kt on 120 hp. Scale that down to slower speeds would be 12.5 kt on 15 hp and 6.25 kt on 2 hp.

Cats seem well suited to super efficient trawler type travel. Easy to push at low speed, lots of surface usually available for solar. I could envision electric propulsion on each hull, a big batt bank, and a genset sized where it could sustain propulsion 24/7 without solar. Domestics run off the batt bank. The downside here is that the genset would need to be fairly large to suit propulsion, and then it is too big to be efficient just serving domestic needs. So then get another smaller gen?? Run the big gen just to charge?? And then there is the conversion losses going from diesel to elec to prop. But that loss is probably minimal compared to the inefficiency of running a too large of a diesel at low power setting, as most of us do now.

It seems any of these layouts require a very active level of management to run. That is fun for some folk, but not for others.

Just thinking aloud...

Re :Battery powered propulsion

Just to put battery vs diesel into perspective the familiar single wet cell deep cycle GP 27 battery holds about 1500 watts or 1.5 KWh when new and fully charged. It can produce 1.5 KW energy for one hour, then it is dead. At high discharge rates energy delivery is less than that and shown on the data sheets linked below but ignored for clarity.

http://www.trojanbattery.com/pdf/TRJN0111_ProdSpecGuide.pdf



Looking at engine makers spec sheets you will often see both a hp and KW power rating. 946 watts equates to 1 hp. The Hp and KW ratings have no time limit as long as fuel is available.



If a boat needs 25 HP to move it satisfactorily we need about 23.6 KW (25*946=)continuously.



Rounding everything off to simple numbers that 23KW power, or 25 HP, equates to 15 of the previously mentioned GP 27 batteries full energy content. (full discharge) ( 23/1.5=).



15 batteries may not seem excessive until you realize that the batteries will use up their 23 KW in one hour while the diesel will produce 23 KW until it runs out of fuel.



Batteries are indeed getting better but they would have to get better by 500% to power that same boat 5 hours. Liquid fuels have high energy content per gallon or cu ft. Tough to beat with a stored energy system like a battery.

1hp = 0.746kW.

bayview said:

Re :Battery powered propulsion

Just to put battery vs diesel into perspective the familiar single wet cell deep cycle GP 27 battery holds about 1500 watts or 1.5 KWh when new and fully charged. It can produce 1.5 KW energy for one hour, then it is dead. At high discharge rates energy delivery is less than that and shown on the data sheets linked below but ignored for clarity.

http://www.trojanbattery.com/pdf/TRJN0111_ProdSpecGuide.pdf



Looking at engine makers spec sheets you will often see both a hp and KW power rating. 946 watts equates to 1 hp. The Hp and KW ratings have no time limit as long as fuel is available.



If a boat needs 25 HP to move it satisfactorily we need about 23.6 KW (25*946=)continuously.



Rounding everything off to simple numbers that 23KW power, or 25 HP, equates to 15 of the previously mentioned GP 27 batteries full energy content. (full discharge) ( 23/1.5=).



15 batteries may not seem excessive until you realize that the batteries will use up their 23 KW in one hour while the diesel will produce 23 KW until it runs out of fuel.



Batteries are indeed getting better but they would have to get better by 500% to power that same boat 5 hours. Liquid fuels have high energy content per gallon or cu ft. Tough to beat with a stored energy system like a battery.

Click to expand...

And that is why Lead is Dead.

I use LiFePO4 and would never even try electric propulsion with lead acid batteries. My early proof of concept is an electric kayak that with just 64 lbs of lithium gives me 80 nm range.

The above mentioned Motorcat 30, while not as efficient as my kayak, would consume less than 300 Whr per mile at 5 kt. Thus a 36 kWhr lithium bank good to 80% DOD would give a range of 100 miles. That is only 750 lbs of LiFePO4 cells.

Thanks SKi, brain fart there.

It should be 12 Batteries not 15, sorry but I could not edit the post to correct it

So bob how much more power is in the equivalent of a gp27 with Li technology??

I don't think you would use 25 HP on your kayak


2X??

This is an edit of the previous post to correct the 746 watts per hp error.


Re :Battery powered propulsion

Just to put battery vs diesel into perspective the familiar single wet cell deep cycle GP 27 battery holds about 1500 watts or 1.5 KWh when new and fully charged. It can produce 1.5 KW energy for one hour, then it is dead. At high discharge rates energy delivery is less than that and shown on the data sheets linked below but ignored for clarity.

http://www.trojanbattery.com/pdf/TRJN0111_ProdSpecGuide.pdf



Looking at engine makers spec sheets you will often see both a hp and KW power rating. 746 watts equates to 1 hp. The Hp and KW ratings have no time limit as long as fuel is available.



If a boat needs 25 HP to move it satisfactorily we need about 18.9 KW (25*746=)continuously.



Rounding everything off to simple numbers that 18KW power, or 25 HP, equates to 12 of the previously mentioned GP 27 batteries full energy content. (full discharge) ( 12/1.5=).



12 batteries may not seem excessive until you realize that the batteries will use up their 18 KW in one hour while the diesel will produce 18 KW until it runs out of fuel.



Batteries are indeed getting better but they would have to get better by 500% to power that same boat 5 hours. Liquid fuels have high energy content per gallon or cu ft. Tough to beat with a stored energy system like a battery.

bayview said:

So bob how much more power is in the equivalent of a gp27 with Li technology??


2X??

Click to expand...

Like night and day for many reasons. A group 27 high end is 105 ahr on the easy 20 hour rate and weighs 57 lbs.

My 100 ahr LiFePO4 cells is derived from a brutal 1 hour rate and weighs 31 lbs.

If the group 27 got its ahr rating from a 1 hour test (pulling 100 amps for 1 hour instead of 5 amps for 20 hours) it would be empty in 20 minutes due to Peukert effect and deliver 32 ahr.

Now move on to usable ahr, lead 50% DOD, LiFePO4 80% DOD. If the load is 100 amps, you have 10 minutes of run time on the lead acid whereas you would have 48 minutes run time on the battery that weighs 1/2 as much.

Cycle life, 400 cycles group 27, 2000 cycles LiFePO4.

Voltage sag, a lot at high current draw for LA, nil for lithium.

Charge acceptance, for the same reason you don't have voltage sag, you get outstanding charge acceptance with LiFePO4.

There is more, but you get the idea.

I guess I missed it but how many KW rating in a 27 size equivalent?

bayview said:

I guess I missed it but how many KW rating in a 27 size equivalent?

Click to expand...

100ah, discharge in 1hr, that's 100a. Assuming 12v, that's 1.2kW for an hour.

bayview said:

I guess I missed it but how many KW rating in a 27 size equivalent?

Click to expand...

A kWhr rating isn't quite comparing apples to apples when concerning the size of the load.

A LA group 27 would be at the 20 hour rate 1260 Whr with a 5 amp load.

At 50% DOD (recommended for LA for good cycle life) gives a usable 630 Whr.

I have a couple of 100 ahr LiFePO4 that are a bit smaller than a group 27 and 1/2 the weight.


One of these is 1300 Whr with a 100 amp load, and higher with the common 5 amp load. Usable at 80% DOD is 1040 Whr.

The main thing to remember is this, at a 100 amp load....

The LA group 27 has 192 usable Whr

The LiFePO4 has 1040 usable Whr.

I should have mentioned that the ideal cats for this application are no different than most cats, that being "weight sensitive". A big bank of conventional batteries would quickly eat up your bridge-deck clearance and performance efficiency.....all the more reason to utilize the lightest possible storage.

healhustler said:

I should have mentioned that the ideal cats for this application are no different than most cats, that being "weight sensitive". A big bank of conventional batteries would quickly eat up your bridge-deck clearance and performance efficiency.....all the more reason to utilize the lightest possible storage.

Click to expand...

Your right, have to watch the weight. While 750 lbs of lithium batteries sounds like a lot of weight, consider the other areas weight is saved with that size propulsion/house bank. No AC gen set needed, just a inverter. Since the bank is also the house bank, save 320 lbs over the common (4) 6 volt golf cart batteries. Weight savings of (2) Torqeedo 4.0 vs (2) 60 hp outboards is another 300+ lbs, so it is a wash on weight. Of course if you did it with lead acid batteries, the cat would be a slug.