300hp Diesel Outboards

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I’ll be curious to see if the commercial guys buy in. At double the price to comparable hp gas engines the recreational market might be a tough sell. How many gas engines get worn out? It will be interesting to see the performance numbers of these vs gas though, that might be the main selling point.
 
Nope, at $55K each I'd never be a player for something like that. Nice idea, great concept, poor presentation and production.
 
These new diesel outboards were developed for the commercial/military market where diesel is often the only fuel available or is mandated.


But I have to hand it to them for making them fresh water cooled which provides much longer life than the typical outboard. I suspect 99% of outboards die of corrosion, not internal wear.



David
 
The Yanmar diesel outboards never took off either.
 
They are very expensive but I suspect you will be seeing them on DNR, Coast Guard, and in the commercial market.

My 120 hp F.L. is all I need.

pete
 
Greetings,
They have the right idea in Thailand IMO. Longtail boats.



iu



 
Its interesting that gas outboards started small....and then grew as time went on....the Diesels start out big...hopefully they can shrink over time. Something like a 150 or 200 on a boat like the TT35 ( sans production issues ) would be a home run I think.
 
Benthic2 said:
Its interesting that gas outboards started small....and then grew as time went on....the Diesels start out big...hopefully they can shrink over time. Something like a 150 or 200 on a boat like the TT35 ( sans production issues ) would be a home run I think.
Click to expand...

The Yanmar diesel outboards of around 20 years ago were 30hp from memory

Trying to find that info I see Yanmar are trying again

DTORQUE TURBO DIESEL OUTBOARD ENGINE - 50 HP
The Neander Dtorque turbo diesel outboard engine sets a new benchmark in diesel engineering. The 804 ccm twin-cylinder aluminum powerhead delivers 50 hp at the propeller shaft
Click to expand...

https://www.yanmarmarine.com/dtorque/
 
There are continued efforts on diesel outboard. Perhaps there is some potential on commercial boats. However, giving those 300's on the boat they were on a quick look, I see the following issues. 1-Cost-Double 2-Weight-50% more. 3-Performance, specifically on that boat with twin Yamaha 425's, it will run 62 mph vs. the 38 mph of the Cox Diesel and it would run between 50 and 55 mph with twin 300 Yamahas.

I keep waiting for Cox and a boat builder to pair up a pairing that makes sense in the market. Perhaps a trawler outboard where speed and weight aren't really factors and then see if anyone will pay for the convenience of diesel.
 
Interesting article. While I understand the comments about cost, perhaps they miss the potential savings. The trial is on a speed boat. Consider one or two of these downrated to trawler engine sizes. Using outboards vs inboards frees up tremendous space - engine room becomes a utility room. Apart from saving inboard engine cost, it saves transmission and drive components including shafts and props. Installation costs are substantially lower. So, I think there are a number of beneficial offsets to the cost, which will likely come down if the consumer market accepts the approach. Though, my guess is installing one of these vs the conventional approach will save money even today if all costs are figured in. On the other hand, I always thought the US did not permit diesel outboards for environmental reasons.
 
Chrisjs said:
I always thought the US did not permit diesel outboards for environmental reasons.
Click to expand...

Generally specific technologies aren't banned, but it's quite likely that up to this point, it's just been too hard to make one that meets the emissions requirements and is affordable enough and practical. Plus, weight is a concern for outboards and conventionally, diesels are heavy.
 
I can see o/b's being designed onto/into naval architecture for new boats; wherein weight distribution can readily be factored into a boat's design.

General circumstances regarding pluses/minuses on many fronts of i/b - vs - o/b will be sussed out by boat designers and owners.

What I have hard time seeing is adding o/b's heavy weight as new power source to the back of boats that originally were designed for i/b engine weight placement. Problem here is weight distribution and therefore altered boat handling conditions in and during many types of sea conditions.

I know that "ballast" can be added to [best as possible] overcome some of the weight distribution change... But... IMHO, a boat that needs ballast-weight haphazardly added in order to try and compensate for some other substantially altered weight distribution circumstance is simply not the wisest maneuver to do to any boat.
 
Admittedly usually midships, but combined weight of 500 gallons diesel, 250 gallons water, and 25 gallons of blackwater is approx. 5,700 lbs. that could be positioned more forward to offset stern weight. Also, figure the weight of prop(s), drive shaft(s) that are no longer at the stern, and heavy batteries that can be relocated from engine room. While I agree that refitting an existing boat would be a challenge and not worth the effort, I can easily see the advantages of new designs with outboard(s) vs inboards. Just think, engine replacement - disconnect a few cables and fuel lines and get a crane, not to mention easier access for dockside repairs!! For practical purposes access for all routine maintenance would need to be accessible from the vessel - can't see standing in the dinghy trying to change a part while underway!!
 
Chrisjs said:
Admittedly usually midships, but combined weight of 500 gallons diesel, 250 gallons water, and 25 gallons of blackwater is approx. 5,700 lbs. that could be positioned more forward to offset stern weight. Also, figure the weight of prop(s), drive shaft(s) that are no longer at the stern, and heavy batteries that can be relocated from engine room. While I agree that refitting an existing boat would be a challenge and not worth the effort, I can easily see the advantages of new designs with outboard(s) vs inboards. Just think, engine replacement - disconnect a few cables and fuel lines and get a crane, not to mention easier access for dockside repairs!! For practical purposes access for all routine maintenance would need to be accessible from the vessel - can't see standing in the dinghy trying to change a part while underway!!
Click to expand...

"... can't see standing in the dinghy trying to change a part while underway!!"

LOL X 2

Many items to overcome. If o/b's can become an often desired option there will be another sales point for boat builders to "sell" people on.

Myself... preferred engine and driveline layout in power boats will likely remain as i/b engine hooked to direct drive transmission ratio with through hull shaft and prop.
 
Chrisjs said:
Admittedly usually midships, but combined weight of 500 gallons diesel, 250 gallons water, and 25 gallons of blackwater is approx. 5,700 lbs. that could be positioned more forward to offset stern weight. Also, figure the weight of prop(s), drive shaft(s) that are no longer at the stern, and heavy batteries that can be relocated from engine room. While I agree that refitting an existing boat would be a challenge and not worth the effort, I can easily see the advantages of new designs with outboard(s) vs inboards. Just think, engine replacement - disconnect a few cables and fuel lines and get a crane, not to mention easier access for dockside repairs!! For practical purposes access for all routine maintenance would need to be accessible from the vessel - can't see standing in the dinghy trying to change a part while underway!!
Click to expand...

I can see a lot of advantages to outboards, but not to diesel vs. gas. I have a friend who is a captain and has run a Tiara 43 LS several times recently and it's a very impressive boat with triple Yamaha 425's. It outperforms a similar Tiara with twin 725 Volvo's or 715 Cummins at a significant cost savings. There are now some very large center consoles with outboards, several over 50'. A few "pocket trawlers" with outboards and very happy owners. The expansion continues and outboard diesels continue to be discussed, prototyped and even built, but haven't yet been successful at creating a market.
 
One draw back to outboards....is that a 30 foot inboard becomes a 35 foot outboard, with the accompanying increase in marina/dockage/storage fees.

I would think some of the weight could be offset by a deep, hollow ( or foam filled ) swim platform.
 
Benthic2 said:
One draw back to outboards....is that a 30 foot inboard becomes a 35 foot outboard, with the accompanying increase in marina/dockage/storage fees.
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That is what Miz Trom was complaining about when they found their 35 foot TT35 was actually 43'.
 
I visualize many problems as well as many improvements regarding outboard motor capabilities/situations in comparison to inboard engine circumstances.

Appears to me that with straight drive, outdrive, jet drive. pod drive and now outboard drive selections as features available to larger boat purchasers... the scope of power train compromise-decisions gets another rung on the ladder... for buyers to ponder!

For several reasons; IMO, straight drive inboard is the best marine drive line. The other choices do have some high points such as mabe extra inboard room and maybe better maintenance/replacement access.

Will be interesting to see direction the marine industry heads for promoting which type of boat drive train.
 
I visualize many problems as well as many improvements regarding outboard motor capabilities/situations in comparison to inboard engine circumstances.

Appears to me that with straight drive, outdrive, jet drive. pod drive and now outboard drive selections as features available to larger boat purchasers... the scope of power train compromise-decisions gets another rung on the ladder... for buyers to ponder!

For several reasons; IMO, straight drive inboard is the best marine drive line. The other choices do have some high points such as mabe extra onboard room and maybe better maintenance/replacement access.

Will be interesting to see direction the marine industry heads for promoting which type of boat drive train.
 
Art said:
Will be interesting to see direction the marine industry heads for promoting which type of boat drive train.
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Where they've headed is clear and that's to outboards. Stern drives have fallen off tremendously. Outboards have even taken some inboard business in the 40' range or so. A lot of people on the coast are not buying small inboards but turning to Center Console instead. The small SF market dissolved into CC.

I believe traditional inboards will remain rather stable now. I think pods will gain some share but even Volvo is compromising the pod growth in now offering their EVC (Electronic Vessel Control) so that the docking and handling can be achieved without pods. I think stern drives will just continue to drop until they become very rare. I think jets will continue to go through periods of gaining and then losing. I think outboards do pose a threat to jets in 20-30' boats. They can match the jet performance which stern drives never could.

No, outboards haven't impacted trawlers appreciably yet, but that's the only part of the under 50' boat market they haven't. Outboards greatly outperform inboards on a Tiara 43' or stern drives on a Sea Ray Sundancer 32'.

Now diesel inboards will definitely outlast outboards, but not enough to offset the cost or the performance advantages of outboards on non-trawlers up to 40' or more.
 
BandB said:
Where they've headed is clear and that's to outboards. Stern drives have fallen off tremendously. Outboards have even taken some inboard business in the 40' range or so. A lot of people on the coast are not buying small inboards but turning to Center Console instead. The small SF market dissolved into CC.

I believe traditional inboards will remain rather stable now. I think pods will gain some share but even Volvo is compromising the pod growth in now offering their EVC (Electronic Vessel Control) so that the docking and handling can be achieved without pods. I think stern drives will just continue to drop until they become very rare. I think jets will continue to go through periods of gaining and then losing. I think outboards do pose a threat to jets in 20-30' boats. They can match the jet performance which stern drives never could.

No, outboards haven't impacted trawlers appreciably yet, but that's the only part of the under 50' boat market they haven't. Outboards greatly outperform inboards on a Tiara 43' or stern drives on a Sea Ray Sundancer 32'.

Now diesel inboards will definitely outlast outboards, but not enough to offset the cost or the performance advantages of outboards on non-trawlers up to 40' or more.
Click to expand...

What you say is basically true.

However, I feel that two to several o/b's hanging off stern of larger, multi cabin, multi head, full galley, comfortable salon, sun deck, fly bridge and swimming platform [used for swimming, loading onto tender and other "elbow room" requiring endeavors] pleasure boats [call em"trawlers" if you like] will run into steep headwinds for boat ownership general public acceptance.

Next decade should have ups and downs re usage of o/b's as power source... for bigger, fully equipped, comfort filled pleasure boats [trawlers included].
 
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