Diesel Engine choice question

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All, thanks for great info. Need one more piece of information to keep the Admiral on my vessel happy (it is cheaper to keep her happy than have her leave me at the next port): If I go with a Helmsman 43 (or similar vessel weight about 45K loaded) with a semi-displacement hull and a 480HP Cummins QSB 6.7, is 12-13 knots a cruise speed or WOT? Typical trips, we will be running from Hilton Head to Charleston SC, or from Hilton Head to St. Augustine (against current), Key West, etc., how long on either of those trips can I run the vessel WOT with adverse effects?

This is just my opinion, however if you want to travel for any length of time at 12-13 knots, get a different kind of boat. You won't like cruising at that speed with that boat. 6-9 knots will be comfortable. 7-8 knots will be ideal.

However, we have a Helmsman 43 owner here on TF who can give you better information.
 
David that’s great. 12-13 is perfect! Thanks

Here is another data point https://web.archive.org/web/20061018102952/http://www.mainship.com/fueleconomy/yanmar3.html

Mainship, in their last years of existence worked with Yanmar and Cummins to do performance tests of their engines in various Mainship models. Here is the page for the Trawler 43, a similar boat in terms of length and weight to the Helmsman. Those boats were only offered in twins, but look at the combined gph at lower speeds. GPH is closely related to hp.

Like I said before the Cummins QSB 6.7 480 while producing 300 hp and pushing the boat to 12-13 kts should burn about 16 gph. Looking at the top table with twin Yanmar 370s the closest point is 14.8 kts at 17.2 gph combined. Extrapolating downward from 17.2 to 16 and noting that these tests are 5-10% optimisitic (not really loaded) gets you into the 12-13 kt bracket.

But lets hope the Helmsman 43 owner chimes in and he has the big engine. Or if he has the smaller engine, what is the wot speed of the boat. If he only has the 250 hp engine and it can do 11 kts wot, then I am pretty sure that the 480 hp version making 300 hp will do at least 12 kts cruising.

David
 
Rather than horsepower, you should look at engines that have a higher rating than recreational. Heavy duty or continuous being best. They will last longer, are designed to be rebuildable, and probably give better fuel usage if approaching or exceding hull speed.

Also look at the speed you want to travel and compare each engine to fuel usage tables.
 
Lepke,
Why should one get (buy w their money) a commercial engine for a pleasureboat?
Makes no sense to me.
Pleasure boat engines die from neglect not hours. Seldom does a pleasureboat engine accumilate enough hours to get worn out even w a pleasureboat rating. There are pleasureboat people that can use a commercial engine but they are rare. Perhaps Richard on Dauntless? This is just my opinion however.
 
Lepke,
Why should one get (buy w their money) a commercial engine for a pleasureboat?
Makes no sense to me.
Pleasure boat engines die from neglect not hours. Seldom does a pleasureboat engine accumilate enough hours to get worn out even w a pleasureboat rating. There are pleasureboat people that can use a commercial engine but they are rare. Perhaps Richard on Dauntless? This is just my opinion however.

Eric, there's a big difference between displacement hulls using 25 to 50% of an engines rated horsepower and a planing or semi planing hull running continously at 75% of rated HP. The original turbo Cummins B motor was rated for 210 Hp and virtually indestructible. Double the HP by winding the rpm up and boosting fuel and turbo pressure is not a recipe for long engine life.

Bet Richard on Dauntless is running his Lehman at less than 40% of rated output.

Ted
 
This is data on the Helmsman 43 with a 380 hp Cummins
source: Helmsman 43 - Sea Magazine

When we exited the no-wake zone, we upped the throttle to 1100 revs and made 5.3 knots while burning 1.2 gph. At 2000 revs, we burned 4.9 gph while moving along at 8.3 knots. When we upped the engine speed to 2500 rpm, we moved along at 9.5 knots while burning 8.4 gph. At 3000 rpm, we burned 16.3 gph and made 10.5 knots.
 
" is running his Lehman at less than 40% of rated output. "

The WOT rated output is little help in deciding the good spot for cruising RPM.

The important concept is to be at least at 50% - 60% (or so) of the engines rating at CRUISE RPM .

The operating RPM, not the possible WOT RPM is what decides if the engine is loaded high enough to "live long and prosper".
 
" is running his Lehman at less than 40% of rated output. "

The WOT rated output is little help in deciding the good spot for cruising RPM.

The important concept is to be at least at 50% - 60% (or so) of the engines rating at CRUISE RPM .

The operating RPM, not the possible WOT RPM is what decides if the engine is loaded high enough to "live long and prosper".
If you can reach full rated RPM of the motor (have the correct prop pitch), running a Lehman at normal cruise RPM isn't going to be an issue. Now if it's over propped, all bets are off. Same for an old Detroit.

Ted
 
This is data on the Helmsman 43 with a 380 hp Cummins
source: Helmsman 43 - Sea Magazine

When we exited the no-wake zone, we upped the throttle to 1100 revs and made 5.3 knots while burning 1.2 gph. At 2000 revs, we burned 4.9 gph while moving along at 8.3 knots. When we upped the engine speed to 2500 rpm, we moved along at 9.5 knots while burning 8.4 gph. At 3000 rpm, we burned 16.3 gph and made 10.5 knots.

That data doesn't portend well for the boat hitting 12-13 kts putting out 300 hp with the higher output engine.

The test boat was probably underpropped as it burned 16 gph at wot for a 380 hp engine. Should have burned 18-19 if propped right. The 16 gph as reported is about 300 hp which is the maximum I would cruise the 480 hp engine at. So the higher output engine will cruise at the same speed- 10.5 kts.

David
 
It is not the first time that I ask that question and never received much answer, why is that?
I do not own a volvo nor have any involvement with this brand just try to educate myself.
Only thing I know about these engine is that I have friend who got a new boat built (not a trawler) and put a Volvo in it (don't know the exact model something around 450ch) and it is nicely running and quite fuel conservative for the speed.

May you elaborate?

L

Lou, That is a Mantra spoken whenever Ancora sees the question asked. I do recall that once, within the last couple of years, he admitted that his own Volvo has been providing good servie for a long time, and that he is not trying to get rid of it or the boat it is in.
He may have had poor service from his local service centre, but that alone is not a sufficient reason for someone else to run from a proven, quality brand.
 
Have not had poor service from my local VOLVO service center as I do all my own engine work. There is not one dedicated VOLVO dealer in North America so finding VOLVO parts is a challenge. If you are not concerned about absurdly high prices and lack of availability of repair parts by all means...go green.
 
Eric, there's a big difference between displacement hulls using 25 to 50% of an engines rated horsepower and a planing or semi planing hull running continously at 75% of rated HP. The original turbo Cummins B motor was rated for 210 Hp and virtually indestructible. Double the HP by winding the rpm up and boosting fuel and turbo pressure is not a recipe for long engine life.

Bet Richard on Dauntless is running his Lehman at less than 40% of rated output.

Ted

Ted,
Still rec boat engines should be fine running at 75% load for the number of hours rec boat engines are expected to last. Too many trawler skippers think their engines need to last forever ... they don’t. But each engine is different. Mine would do 75% for thousands of hours but it’s NA.
 
I recently told my wife our new Cummins will outlive us, and likely our adult kids as well.
 
Volvo and Westerbeke are both guilty of extortion and price fixing targeting their existing end users. Both companies are predatory in their financial punishment of people that have the misfortune to own their products.

Example: valve made by Mitsubishi engine used in Westerbeke genset in Westerbeke packaging is $73. Same valve in Mitsubishi packaging is $23. Headgasket $49 vs $211. Volvo appears to use the same business model.

Not saying either is bad equipment, on the contrary, both build a quality product but both have an ethical problem. Best to recognize that going in.
 
Volvo and Westerbeke are both guilty of extortion and price fixing targeting their existing end users. Both companies are predatory in their financial punishment of people that have the misfortune to own their products.

Example: valve made by Mitsubishi engine used in Westerbeke genset in Westerbeke packaging is $73. Same valve in Mitsubishi packaging is $23. Headgasket $49 vs $211. Volvo appears to use the same business model.

Not saying either is bad equipment, on the contrary, both build a quality product but both have an ethical problem. Best to recognize that going in.
Isn't it the same for anything branded "marine"? :)

L
 
That’s interesting Hills,
You would buy the most popular. And that turns your crank to have the most popular things? Like teen aged girls HaHa.
I can see not buying a boat w a Volvo because of expensive parts. I have a very unpopular engine in my boat. I don’t know of anybody else on TF that has one in their boat. Had it for 12 years and haven’t bought any Mitsubishi parts other than filters and the like.
Volvo engines must be really bad to require enough parts to get the reputation they have. If they were as good as my Mitsu knowbody would know the parts were expensive. Also needing engine parts could have a lot to do w when the majority of Volvo’s were sold into new boats. Or who buys Volvos. Many Volvos get more or less forced on buyers by builders installing Volvos in their new boats. Just some thoughts.

But your buying the most popular engine because of it’s popularity makes me wonder if you really like your things. Assuming you buy most other things (cars, TVs, clothing, your boat) because they are the most popular and that may not be what you do. Perhaps this just applies to boat engines. :confused:

It's all about resale. If the boat is new construction, I would get whichever power level most buyers choose, thus when you go to sell it, which will happen, usually sooner than the buyer would like, you will have the most desirable configuration. The cost of the bigger hp rating is seen only at initial purchase and not during normal use so it is not a constant drag on finances, but will help you either sell faster or at a higher price.


Indeed, I do buy popular things: popular shopping centers, popular apartment buildings, Collector cars, homes in popular neighborhoods, etc. And when they stop giving the pleasure or income I want, I sell them, invariably at a large profit since, for some odd reason lots of other people seem to want to buy them from me.. weird huh? Can you think of any explanation?

As far as my relationship to my possessions, I LOVE people and pets, not stuff or material things.

I enjoy the heck out of playing with my toys, but in the end they are just stuff. Mostly interchangeable stuff, too: in the last year, I have sold two Classic Motorcycles I restored myself 30 years ago: a Laverda and a Paul Dunstall Cafe racer. I also sold a Lotus 11 replica LeMans car i built in my shop over 7 years from a kit and a 550hp Campbell lake boat, that I rescued for a scrap pile. I loved building these toys, loved planning construction and working on them, loved using them and wearing them out. But I also loved seeing them drive away on the back of sombody elses truck, knowing that they had paid me good money and that they would continue to give them a good home.

As far as liking my things, most stuff is pretty much all the same: what is the practical difference between a new S-class, a new 7-series, a new A8, or a top of the line Kia or Hyundai or Tesla. Ive been in all of them, owned a few and other than the Tesla they are all peas in pod: just stuff.... it sounds like you like to build an emotional connection with your things, I Do Not, I save that for the people in my life instead.
 
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It's all about resale. If the boat is new construction, I would get whichever power level most buyers choose, thus when you go to sell it, which will happen, usually sooner than the buyer would like, you will have the most desirable configuration. The cost of the bigger hp rating is seen only at initial purchase and not during normal use so it is not a constant drag on finances, but will help you either sell faster or at a higher price.


Indeed, I do buy popular things: popular shopping centers, popular apartment buildings, Collector cars, homes in popular neighborhoods, etc. And when they stop giving the pleasure or income I want, I sell them, invariably at a large profit since, for some odd reason lots of other people seem to want to buy them from me.. weird huh? Can you think of any explanation?

As far as my relationship to my possessions, I LOVE people and pets, not stuff or material things.

I enjoy the heck out of playing with my toys, but in the end they are just stuff. Mostly interchangeable stuff, too: in the last year, I have sold two Classic Motorcycles I restored myself 30 years ago: a Laverda and a Paul Dunstall Cafe racer. I also sold a Lotus 11 replica LeMans car i built in my shop over 7 years from a kit and a 550hp Campbell lake boat, that I rescued for a scrap pile. I loved building these toys, loved planning construction and working on them, loved using them and wearing them out. But I also loved seeing them drive away on the back of sombody elses truck, knowing that they had paid me good money and that they would continue to give them a good home.

As far as liking my things, most stuff is pretty much all the same: what is the practical difference between a new S-class, a new 7-series, a new A8, or a top of the line Kia or Hyundai or Tesla. Ive been in all of them, owned a few and other than the Tesla they are all peas in pod: just stuff.... it sounds like you like to build an emotional connection with your things, I Do Not, I save that for the people in my life instead.
Well the same for everything, what is the difference from a grand cru de bordeaux vs a 5$ wine at the nearest supermarket, it is just wine. What is the difference between a grand chef restaurant vs PFK this is just food. What is the difference between driving a Porsche and an Honda Civic, it is just a car. And I would not even go to the woman or drug subject as it would too much controversial... I would risk a last one, what is the difference between shooting a bullet in my head at 20 or dying at 95 in my boat looking at a sunset, at the end same result. But for sure you are true, when you don't know how to appreciate things you cannot make any difference.
And don't take it personal, nothing against you, but yes these are material things, like my boat is, and if you know how to appreciate these things and how much lucky you are to be able to appreciate them, the journey is far different.

L
 
Like my non-turbined, four-cylinder John Deere. Does everything asked as long as it isn't expected to provide speed beyond the full-displacement capabilities of the boat.
 

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To me the Key point is most boat engines are simply engines purchased from the engine MFG and then marinized.

An engine that is sufficient for the task will be lowest price produced in the greatest numbers.

Kabota lawn equipment seems great at noisemaker operation.

VW and BMW diesels never made the grade for propulsion.

The question then becomes pricing spare parts in your area for the brand desired .

Farm derived engines like JD (even if only marinized from a source) have large price constraints , so make a good long term choice.

For the distance voyagers a second question becomes , why marinize?

A Keel Kooled , dry stack setup is a delight to live with and virtually any engine , new or used, can be selected.


Paying 3x - 5x extra for some paint on a marinization is not a boating requirement.
 
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For the distance voyagers a second question becomes , why marinize?

A Keel Kooled , dry stack setup is a delight to live with and virtually any engine , new or used, can be selected.

Besides Nordhavn, who offers a keel cooled option, specially, in boats under 50'?
 
Besides Nordhavn, who offers a keel cooled option, specially, in boats under 50'?


None that I am aware of. All of the full displacement trawlers I mentioned in the beginning of this thread except Nordhavn use raw water circulated exchangers with water injection into the exhaust.


Dry exhaust systems require a large vertical chase right in the middle of the cabin and up behind the fly bridge and most builders don't want to waste that space much less deal with external keel coolers.


David
 
Well the same for everything, what is the difference from a grand cru de bordeaux vs a 5$ wine at the nearest supermarket, it is just wine. What is the difference between a grand chef restaurant vs PFK this is just food. What is the difference between driving a Porsche and an Honda Civic, it is just a car. And I would not even go to the woman or drug subject as it would too much controversial... I would risk a last one, what is the difference between shooting a bullet in my head at 20 or dying at 95 in my boat looking at a sunset, at the end same result. But for sure you are true, when you don't know how to appreciate things you cannot make any difference.
And don't take it personal, nothing against you, but yes these are material things, like my boat is, and if you know how to appreciate these things and how much lucky you are to be able to appreciate them, the journey is far different.

L

You have set up a strawman and knocked it down, good for you. Unfortunately, it is not a choice between one single high quality item and one single low quality item. It is a choice in life among 5 or more high quality things: not a choice between $5 wine and a first growth Bordeaux, but between 5 grand cru. Not a choice between a Porsche and a Civic, but between a Porsche, an R8, a Ferrari, a Lamborghini, and a McLaren. Again I have driven them all and IMHO on American highways and cities there isn't a dimes worth of difference between them: their limits are so far beyond what I as a driver can explore on a public highways as to be unobtainable. And don't get me started on wine, we are trying to thin out an 800 bottle cellar in anticipation of moving from California to Florida (mostly Grand Cru Burgundies and older Barolos), so I do have some interest in wine even though I drink craft beer on a daily basis.

Perhaps my more practical approach to the business side of life is what has allowed me to fund the the more important part so well? As well as to practice the connoisseurship needed to appreciate such a lifestyle. Besides, just what IS the functional difference between an S-class and a 7-series and an A8, but the badge and the image, I've had them all and they all get the job done of moving me from here to there in safety and comfort. But none is really any better than the other, subtly different, yes, but not better. Unless you feel that branding make a product better......
 
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To me the Key point is most boat engines are simply engines purchased from the engine MFG and then marinized.

An engine that is sufficient for the task will be lowest price produced in the greatest numbers.

Kabota lawn equipment seems great at noisemaker operation.

VW and BMW diesels never made the grade for propulsion.

The question then becomes pricing spare parts in your area for the brand desired .

Farm derived engines like JD (even if only marinized from a source) have large price constraints , so make a good long term choice.

For the distance voyagers a second question becomes , why marinize?

A Keel Kooled , dry stack setup is a delight to live with and virtually any engine , new or used, can be selected.


Paying 3x - 5x extra for some paint on a marinization is not a boating requirement.

You don't have to go to dry exhaust and keel cooling to use an industrial engine. I have set them up with a remote mounted industrial coolant to sea water heat exchanger and a wet exhaust. Do need to bracket a sea water pump and a coolant head tank. Engine has no idea that it is in a boat. Feed it and it spins!!
 
I have both VOLVO engines and a Westerbeke gen set with extortion priced parts. The difference is that Westerbeke unlike VOLVO, has never told me "we no longer support that product.":nonono:
 
This is data on the Helmsman 43 with a 380 hp Cummins
source: Helmsman 43 - Sea Magazine

When we exited the no-wake zone, we upped the throttle to 1100 revs and made 5.3 knots while burning 1.2 gph. At 2000 revs, we burned 4.9 gph while moving along at 8.3 knots. When we upped the engine speed to 2500 rpm, we moved along at 9.5 knots while burning 8.4 gph. At 3000 rpm, we burned 16.3 gph and made 10.5 knots.



FWIW, that is the same engine that I have in my North Pacific 43. I get about 7 knots at 1450rpm burning 2 gph. WOT will get me to about 11 knots. Very unpleasant.
 
It's all about resale. If the boat is new construction, I would get whichever power level most buyers choose, thus when you go to sell it, which will happen, usually sooner than the buyer would like, you will have the most desirable configuration. The cost of the bigger hp rating is seen only at initial purchase and not during normal use so it is not a constant drag on finances, but will help you either sell faster or at a higher price.


Indeed, I do buy popular things: popular shopping centers, popular apartment buildings, Collector cars, homes in popular neighborhoods, etc. And when they stop giving the pleasure or income I want, I sell them, invariably at a large profit since, for some odd reason lots of other people seem to want to buy them from me.. weird huh? Can you think of any explanation?

As far as my relationship to my possessions, I LOVE people and pets, not stuff or material things.

I enjoy the heck out of playing with my toys, but in the end they are just stuff. Mostly interchangeable stuff, too: in the last year, I have sold two Classic Motorcycles I restored myself 30 years ago: a Laverda and a Paul Dunstall Cafe racer. I also sold a Lotus 11 replica LeMans car i built in my shop over 7 years from a kit and a 550hp Campbell lake boat, that I rescued for a scrap pile. I loved building these toys, loved planning construction and working on them, loved using them and wearing them out. But I also loved seeing them drive away on the back of sombody elses truck, knowing that they had paid me good money and that they would continue to give them a good home.

As far as liking my things, most stuff is pretty much all the same: what is the practical difference between a new S-class, a new 7-series, a new A8, or a top of the line Kia or Hyundai or Tesla. Ive been in all of them, owned a few and other than the Tesla they are all peas in pod: just stuff.... it sounds like you like to build an emotional connection with your things, I Do Not, I save that for the people in my life instead.


Hills,
If it was all about resale you wouldn't buy an MB or a BMW. Two of the worst for resale value along w high maintenance. Those two are usually very pretentious as are their owners. You may just think they drive better. I drive a pretentious car too (Avalon) but I drive it because I like it’s comfort, light steering and roadability. And probably because of it’s documented durability. Unlike your two German cars.
My second car is a VW Golf. Very low on the durability list. I like it almost entirely because of it’s driveability. It’s a low geared turbo 1.8L.
My third car is an 87 Nissan Stanza 4dr. It has an incredible (for it’s age and size) number of features I previously didn’t think they had in small cars. But I love driving it. Shifting and again steering. Unlike the “Avalon” I like it’s narrowness. In Japan there was a law the vehicles must not be wider than “X” number of inches. Narrow. About 1990 the Japanese car sales warranted special models for the U.S. that were wider than the Japanese maximum. I offer this as an interesting side note

No I don’t think you buy your things for resale value but for social value. The things you have are things that others aspire to have (probably friends or people that like you like popular things). The above is the only way I can explain why you bought a Laverda. Never ridden one though.

Thanks for the feedback. Not often I get to talk to somebody very unlike myself that dosn’t turn into an argument.

Also if I had more money I’d probably buy things more like you. I once had an XK Jaguar roadster (57).
 
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None that I am aware of. All of the full displacement trawlers I mentioned in the beginning of this thread except Nordhavn use raw water circulated exchangers with water injection into the exhaust.


Dry exhaust systems require a large vertical chase right in the middle of the cabin and up behind the fly bridge and most builders don't want to waste that space much less deal with external keel coolers.


David

David, the raceway required for Delfin's dry stack is small, and blends in with the layout, so is completely innocuous. The bulkhead heater mounts on one side, and I'm not sure where else that would have gone without the raceway. I don't think the choice of builders to put in wet exhaust has much other to do with than it is cheaper out of the gate. For the owner, dry stack is so much preferable, IMO, that I am surprised it is not at least offered as an option. No salt water in the engine, no impellers, exhaust up high rather than below the nose - seems Superior to me. Pretty rare to see a commercial boat with wet exhaust, at least up where we operate.
 
It's about resale value within its class. If I was shopping for a luxury car with all the modern safety and self driving features, I would buy a Benz or a BMW as opposed to an Jaguar or Cadillac. Actually, when last faced with that sort of choice, I leased, since I wanted to see what electric cars were like and didn't want to buy fast changing technology.
I am pretty sure I actually do know how to tell if one car handles better than another given my long association with motorsports and ownership of a chassis and suspension shop in Los Angeles. As far as reliability goes, the German brands do not seem to breakdown during the warranty or lease period, so who cares?

I guess you win in the reverse snobbery sweepstakes since my owned vehicles are a 2008 Infiniti and a 2008 smart cabriolet (also a 2007 Lotus 11 replica, but toys don't really count). Just sold the 2000 F-250 and got a 2017 model. BTW, my second sports car was an XK-120 FHC that I bought in Berkeley back in '74. The first was a $300 1960 MGA.....

The Laverda made for a great sport tourer and I rode that beast all over the west coast in the late '80s and early '90s. It is the RGS model with the rubber mounted engine and 120* crankshaft so not as raw as the Jota with the 180* crank. Ironically, once I began doing chassis and suspension with AMA Superbike teams, I began riding less and less. Lesson learned: don't make your hobby your job, it turns relaxing fun into work!
 
Volvo and Westerbeke are both guilty of extortion and price fixing targeting their existing end users. Both companies are predatory in their financial punishment of people that have the misfortune to own their products.

Example: valve made by Mitsubishi engine used in Westerbeke genset in Westerbeke packaging is $73. Same valve in Mitsubishi packaging is $23. Headgasket $49 vs $211. Volvo appears to use the same business model.

Not saying either is bad equipment, on the contrary, both build a quality product but both have an ethical problem. Best to recognize that going in.

I don't doubt that a bit but I do wish I could find volvo in different packaging

as I have both westerbeke and volvo the westerbeke I have found parts for easy and cheap just not my volvos
 

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