what to look for in a trawler?

dannc said:

Looks like the boat got 8.6 NM per US gallon of fuel.

Click to expand...

This seems highly unlikely.

The numbers quoted, 1044 hours under way consuming 3000 L of fuel is only .76 usg per hour. That's about 15HP, which should push a 60,000 pound boat at about 5.5 knots in flat calm (Not open ocean) conditions with no wind, 6.5 knots will take twice the fuel, for about 30 HP.

I know a DD 47 (design displacement 70,000 pounds) uses 2.9 gph at 6.6 knots, that's about 52 HP. Why is the 44 burning so much less?

Tad Roberts said:

This seems highly unlikely.
Why is the 44 burning so much less?

Click to expand...

Yes, I noted this thought on a different thread, missed fuel bill I'd guess

sunchaser said:

Yes, I noted this thought on a different thread, missed fuel bill I'd guess

Click to expand...

On that theme, started with full tanks, but on arrival at destination did not refill, leaving it for owners pleasure. Delivery crew just added up fuel they purchased en route?

I may have posted this earlier in this thread, if so, apologies. If anyone wants a seriously ready ocean crossing Diesel Duck, do a Google search on "Doramac". A 46' immaculate, incredibly equipped owned by Randall Johnson. For sale in London. I happened to see this boat about 5 years ago and since then I think they completed most of a circumnav. From their listing, you may not even need to fuel up for the trip back across the Atlantic!

Insequent said:

On that theme, started with full tanks, but on arrival at destination did not refill, leaving it for owners pleasure. Delivery crew just added up fuel they purchased en route?

Click to expand...

We used exactly what we stated - we refueled twice (Madeira & Cape Verde) before heading across to UY.

Ghostrider42 said:

We used exactly what we stated - we refueled twice (Madeira & Cape Verde) before heading across to UY.

Click to expand...

Ok, pretty amazing! Thanks for confirmation.

Ghostrider42 said:

We used exactly what we stated - we refueled twice (Madeira & Cape Verde) before heading across to UY.

Click to expand...

Ghostrider42,

What engine is in the boat?

What RPM was used during the trip?

One of the reasons I like the Diesel Duck design is low fuel usage. I do not want to be running across the water at high speed, so moving along slowly is just fine. I am looking at the Diesel Duck design details and looking at various engine specifications trying to figure out which RPM would give about 1 GPH. This is simple to do.

My concern is that low RPM to get 1 GPH might not be good for the engine. I have a JD tractor and most of the work I do with the tractor does not require PTO speed which is about 2600 RPM. The engine tops out at 3000 RPM. For a few years I would run the engine at about 1600 RPM but used oil analysis showed fuel in the oil. I bumped up the RPMs to 1800ish and no more fuel in the oil. The amount of fuel in the oil was within specifications but I don't want fuel in the oil at all. And I sure would not want fuel in the oil in a boat engine.

I also would prefer to have a normally aspirated engine but looking at JD engines it seems I would have to have a turbo to get the HP specified by the boat design. There are normally aspirated engines around 80-85 HP which seems adequate.

The other issue I have is does the boat rally need all of this HP? The Diesel Duck 48 will use about 14 HP to go 7.4 knots and 40 HP to go 8.8. Well, 7 knots is fast enough for me, so does the boat really need 100+ HP? [SIZE=+2]
[/SIZE]To go 15% faster, takes almost 3 times the HP and corresponding fuel usage.

The engine needs to supply some power and maybe hydraulics but I do not see why the boat needs a 110 HP engine. The higher the HP the worse the fuel burn and I wonder about running the lower RPMs to use less HP to minimize GPH.

Later,
Dan

dannc said:

The higher the HP the worse the fuel burn and I wonder about running the lower RPMs to use less HP to minimize GPH.

Later,
Dan

Click to expand...

Dan: There may be a few moments where the extra HP and torque could be useful...currents, winds, inlets, rivers, tides, etc.. I think you're right about the 85 or so rating, but don't do yourself completely out of spare HP.

My boat originally came with a 90 Volvo but was refit with a 140 Yanmar. I too, feel this is unnecessary HP, but both engines are 3600 RPM, and I'm still turning the same 22 X 13 prop as the Volvo. Thus far, I haven't been able to determine more fuel usage by the Yanmar over the Volvo, maintaining the same speeds over the same waterways. I'd expect that if I kept it nailed that that increased fuel usage would appear, but the figures for 7.5 knots or under are too close to call and nearly identical to the original chart published for Manatee buyers. At least two other Manatee owners whom have tested my boat have noted that a useful increase in "kick" can be felt that helps with handling. When testing their boats, I can't feel it the way they do but for sure the Yanmar revs quicker.

Could it be that Diesel Duck also experienced this with the current power offering and that the additional power could be an asset at times? Maybe at the typical operating range, any increased fuel consumption of their chosen power-plant really hasn't been a significant issue, and the somewhat lower load on the engine hasn't been an issue either.

healhustler said:

Dan: There may be a few moments where the extra HP and torque could be useful...currents, winds, inlets, rivers, tides, etc.. I think you're right about the 85 or so rating, but don't do yourself completely out of spare HP.

...

Click to expand...

My dad had a 33 foot sail boat that was 15,000 pounds and had a 50 HP engine. That seems like a lot of HP for the boat. We had quite a few interesting moments dealing with current in tight spaces in South FLA and the Keys but I can't remember if I ever had to use all of the throttle. If I did have to use full throttle it was not for but a few seconds.

One certainly needs the power but the danged difficult question is how much is enough? It seems like if the HP needed for max speed is 40 HP in perfect conditions having an 80-100 HP would be enough and better for the engine if running at 1 GPH.

I have read that one should use the engine at 50-75% which fits perfectly with my experience with truck and tractor engines. Looking at the performance curves on the JD engines, the 80-85 HP non turbo engines would be running at around 60% where as the 107-135 HP engines would be in the low 50% at one GPH.

Now, one could hang a big alternator on the engine for power generation but since the boats I am drooling over, errr, researching, have a generator it seems that it would be to minimize power generation on the engine and use the genset AND solar and/or wind power.

Fun to think about this stuff with 6-8 inches of snow on the ground while dreaming of a trip to the South Pacific.

Later,
Dan

dannc said:

Fun to think about this stuff with 6-8 inches of snow on the ground while dreaming of a trip to the South Pacific.

Click to expand...

I disagree... It's kinda depressing.

dannc said:

One certainly needs the power but the danged difficult question is how much is enough? It seems like if the HP needed for max speed is 40 HP in perfect conditions having an 80-100 HP would be enough and better for the engine if running at 1 GPH.

Click to expand...

Dan, I believe expecting less than 1.5 GPH is unrealistic.

See post #1 at
http://www.trawlerforum.com/forums/s6/throttle-settings-13708.html#post213178

With a FD hull the proper or correct amount of power is clear cut. Enough to comfortably cruise at 1/2 a knot to 1 knot below hull speed. And another 5 to 10% for unusual circumstances. There really is no need to reach hull speed.

We have the "gotta have lots of extra power" from our automotive culture. Most of us grew up in the 300hp V8 era and we love lots of power.

My FD trawler has 5hp per ton of displacement and I've never run it over 500rpm down from it's rated speed of 3000rpm for more than a minute or two. So I've never used more than 30hp.

BUT w a SD hull much more power and a little bit more speed is a desirable scenario. That's why we have so many over powered SD boats. If more speed (over HS) is what the owner wants to do then he should not have a FD boat. A GB 36 (SD) could run regularly at 15 knots ... Or 8 knots. One could ligitamately have 100hp or 500hp. All depending on what the owner wants to do. So unlike the FD hull the SD has no clear proper amount of power.

After saying that when a SD hull is on the drawing board the NA design's it for a speed range that's suitable for her hull form. A DeFever 49, w sufficient power could be designed to run at hull speed or slightly above. To go much faster one would want a faster hull. To go 2 to 2.5 times HS a hull that is closer to a planing hull would make more sense.

You can run a SD hull like a FD hull but to best pull this off you'd need to re-power and select much smaller engines.

So you could apply the "enough to cruise + 10%" philosophy to basically any boat and never go wanting for more power. One really doesn't NEED more than that. The above applies to FD and SD hulls only.

markpierce said:

Dan, I believe expecting less than 1.5 GPH is unrealistic.

See post #1 at
http://www.trawlerforum.com/forums/s6/throttle-settings-13708.html#post213178

Click to expand...

I think you may be right, or maybe I am afraid you are right, but I have seen 1 ish GPH mentioned here and there so I figure it is a best case number but most likely Unitanium.

The fourth edition of Voyaging Under power has some real world fuel usages in Appendix C and a FEW boats/trips got close to 1 GPH. Most of the entries were getting 1-2 NMPG but the Diesel Ducks were were getting around 4 to almost 5 NMPG. Dora Mac which is for sale got 4.93 which is 1.2 GPH. She has one of the JD engines, 135 HP, which I have been researching. The Idelwild has a passage getting 4.6 NMPG and on their website they mention burning 1.3 GPH. The Idelwild is 30k pounds and has a 55 HP engine so she is in the 4 HP per ton recommendation.

I did see your thread and found it very interesting.

While 1 GPH might be ideal or Unitanium I am still concerned with running the engine to get the best GPH AND maximizing the engine's lifetime/reliability. Course, the engine is just turning that thar prop dohickey, which is another topic.

BTW, am I spending too much time reading about Diesel Ducks when I start recognizing boats? I LOVE the yellow roof on a certain DD. Our sea kayaks are yellow on the top.

Later,
Dan

Tom.B said:

I disagree... It's kinda depressing.

Click to expand...

Hey, it could have been worse, we could have had that ice that was first forecast and we thus lost power! Then no boat talking! I think we got lucky with this storm. <whew> It was bad enough as is.

Later,
Dan

dannc said:

... I LOVE the yellow roof on a certain DD. Our sea kayaks are yellow on the top.

Later,
Dan

Click to expand...

Sorry, a yellow pilothouse roof is a protected trademark. License fee is $500. Send me a PM to arrange payment.

manyboats said:

So you could apply the "enough to cruise + 10%" philosophy to basically any boat and never go wanting for more power. One really doesn't NEED more than that. The above applies to FD and SD hulls only.

Click to expand...

Need? Much of boating isn't about need. It's about what one likes and enjoys. For us, that's significantly more than "need" but we "need" it for our full pleasure.

BandB said:

Need? Much of boating isn't about need. It's about what one likes and enjoys. For us, that's significantly more than "need" but we "need" it for our full pleasure.

Click to expand...

There are needs, and then there are wants.

dannc said:

One of the reasons I like the Diesel Duck design is low fuel usage. I do not want to be running across the water at high speed, so moving along slowly is just fine. I am looking at the Diesel Duck design details and looking at various engine specifications trying to figure out which RPM would give about 1 GPH. This is simple to do.

My concern is that low RPM to get 1 GPH might not be good for the engine. I have a JD tractor and most of the work I do with the tractor does not require PTO speed which is about 2600 RPM. The engine tops out at 3000 RPM. For a few years I would run the engine at about 1600 RPM but used oil analysis showed fuel in the oil. I bumped up the RPMs to 1800ish and no more fuel in the oil. The amount of fuel in the oil was within specifications but I don't want fuel in the oil at all. And I sure would not want fuel in the oil in a boat engine.
Dan

Click to expand...

Wouldn't the newer electronic controlled, hi-pressure, common-rail diesels eliminate this 'excessive fuel' problem at the lower RPM's ??

Diesel Common Rail Injection Facts 1 - YouTube

>My concern is that low RPM to get 1 GPH might not be good for the engine.

The amount of fuel in the oil was within specifications but I don't want fuel in the oil at all. And I sure would not want fuel in the oil in a boat engine. <

Fuel in the oil is usually from the rings not sealing due to too light loading.

The simplest (not cheapest) way to solve the problem is with a CPP and EGT gauge.

The engine can be run a bit harder at low speeds , so the higher combustion pressure can enable proper pressure behind the rings , sealing them .

This stops the slobbering and blowby of light loading, and will extend engine life.

Inshore a cruising prop works fine , but for offshore where the boats displacement will vary as a ton of fuel is consumed , or climbing 8-20 ft waves will require different power levels.

The CPP solves the problem. Controllable Pitch Propeller, not as expensive as you might imagine.

markpierce said:

Sorry, a yellow pilothouse roof is a protected trademark. License fee is $500. Send me a PM to arrange payment.

Click to expand...

Actually a yellow roof is not just a very colorful accent. It is very much a potential benefit in both theft and problems at sea, making the boat far easier to see and identify. We always had our trailer roofs (as in tractor trailers) painted brightly with our logo. We (company I worked for) had two full trailers stolen in about the three year period. Our pilots took one of our company planes and found them each time in less than two hours. In one case they'd driven it about two miles on a dirt drive through the woods to an huge barn deep and out of sight. They were unloading it as police cars descended on them and our pilots watched from overhead. Solved about a dozen other thefts at the same time. Even while unloading, they were already painting the sides of the trailer too. Just weren't aware of the top.

brian eiland said:

Wouldn't the newer electronic controlled, hi-pressure, common-rail diesels eliminate this 'excessive fuel' problem at the lower RPM's ??

Click to expand...

I am pretty sure my tractor engine is a common rail engine. My truck engine had the same problem at the same time. I was driving into an area that I call the Valley of Death because, one it is in a valley, and two, the traffic was just horrible. At the time, the drive from work to home took about 70-80 minutes one way and I would get stuck in traffic for about 10-20 minutes on each leg of the trip. This was stop and go traffic followed by 55 MPH driving. The truck ended up with a bit of fuel in the oil because of idling in the traffic.

Prior to driving into the Valley of Death, the oil was just fine. Now that I do not have to drive into that place the oil has been fine. The truck has a common rail engine.

Later,
Dan

BandB said:

Actually a yellow roof is not just a very colorful accent. It is very much a potential benefit in both theft and problems at sea, making the boat far easier to see and identify. ...

Click to expand...

The selection of a bright yellow roof was for practical reasons: visibility and identification; not a fashion statement.

Underside of Cockpit Covering

markpierce said:

The selection of a bright yellow roof was for practical reasons: visibility and identification; not a fashion statement.

Click to expand...

Speaking of practicality, I saw at one time a very unique solution to the considerable 'glare' that a helmsman can experience when operating a vessel on a bright sunny day while being under a white colored overhead structure. Plaint the overhead a darker color

This can occur often on sailing vessels that have a built-in sun awning of fiberglass that is often white gel coat in color. The helmsman is peering out from under this awning into bright sunlight, and then gets another reflection off the water into the underside of the 'awning'. Its surprising how much glare is eliminated by coloring the underside of that covering a darker, less reflective color.

I've got a photo somewhere, if I can find it.

What I would look for in a trawler is one that has been refitted and upgraded by several owners over the years. Every owner has his favorite thing .. like mechanical, electronics, carpets and beautiful paint, systems like heads, stoves and ground tackle. Over time a boat can be created that would cost way more than it was worth to duplicate. I say look for it. You won't pay much over the average price. Any given model boat is only worth so much on the market.

brian eiland said:

Speaking of practicality, I saw at one time a very unique solution to the considerable 'glare' that a helmsman can experience when operating a vessel on a bright sunny day while being under a white colored overhead structure. Plaint the overhead a darker color ...

Click to expand...

Similarly, my forward cabin roof in front of the pilothouse windows is straw-colored.

>Every owner has his favorite thing .. like mechanical, electronics, carpets and beautiful paint, systems like heads, stoves and ground tackle. Over time a boat can be created that would cost way more than it was worth to duplicate. I say look for it. You won't pay much over the average price. Any given model boat is only worth so much on the market.<

This only works if you select a boat owner that wanted the EXACT same life style that you desire.

If it was set up with systems to cruise and anchor out most of the time it will be a far different outfitting than a weekend dock queen , or a liveaboard on the power hose.

ON bus conversions its called MY Way , and the desirements must match.

You don't haf'ta have EXACTLY what you want.

Just somewhat close.

The other way is to buy the boat you want and then fix and upgrade and change it to what you want. But you'll grow w the boat and want a different after awhile. And it will cost you a ton of boat bucks.

dannc said:

Ghostrider42,

What engine is in the boat?

Click to expand...

135hp + 40hp wing engine

What RPM was used during the trip?

Click to expand...

We alternated btwn the main @ 850rpm and the wing @ 450rpm
and used the sails about 30% of the time. We never dropped the sails all the way down when the seas got rough.

One of the reasons I like the Diesel Duck design is low fuel usage. I do not want to be running across the water at high speed, so moving along slowly is just fine.

Click to expand...

Under normal circumstances you would get 3000nm on the tanks. Less if you speed up to 1000rpm and more if reduced to 550rpm.

I also would prefer to have a normally aspirated engine but looking at JD engines it seems I would have to have a turbo to get the HP specified by the boat design. There are normally aspirated engines around 80-85 HP which seems adequate.

Click to expand...

Yes, anything exc a Volvo or YM - I hate them. Rather have a MB80, Cummins 3.9, Cat or Iveco. A JD, as long as it's not a YM block.

The other issue I have is does the boat rally need all of this HP? The Diesel Duck 48 will use about 14 HP to go 7.4 knots and 40 HP to go 8.8. Well, 7 knots is fast enough for me, so does the boat really need 100+ HP? To go 15% faster, takes almost 3 times the HP and corresponding fuel usage.

Click to expand...

Probably not, but American customers see this big boat and want a big engine. It's just not practical.

Dan, my Dad and I built custom cats for years in Panama. The 50ft used a pair of Westerbeke 44C's and the 42 had a pair of 30C's - naturals. We had built eight or so, when customers wanted more hp. This we refused to do. I put a Cummins 3.3 into a Frers 55 design, but nothing larger.

Currently into a 60ft aluminum plate alloy build that will use a pair of 44C's to power 18kw electric motors.

I own a Diesel Duck 462 hull #5 and we burn 1.6 gallons per hour at 6.5 knots and 1500 RPM. That is close to a liter per mile and we can carry 7,500 liters of fuel.
I'm new to the forum but we have spent the last 7 years aboard Dora Mac and we're now in London, UK

Dora Mac

I'll try to upload a picture of Dora Mac