Diesel's are definitely on the rise. Look at Mercury for example. They now have a 50/50 venture with Cummins on the smaller engines; this has to be a sign of a move for the future.

I spoke with the Cummins guys at the Miami Boat Show and they are tight lipped about a competitive engine to the Yanmar 440, (I believe the Cummins truck (DODGE) engines can make over 440 hp)

I believe they can do this with ease, but I wonder about the competitive weight and cost of the Cummins.

In Europe the diesels are far more common in boats, but this is for the same simple fact as with the cars. Cost of the Diesel vs. Cost of the GAS. Taxes for some reason are way lower on the diesel and this makes them far more attractive, hence their popularity.

The same thing on a different scale is happening here. The boats will never be super fast with a reliable diesel engine, just fast enough to make the idea work. Fountain for example, the 42’ lightning is a faster boat than the same boat with 500 efi’s and Bravo’s while weighing more and still getting three times the fuel mileage. They have reached speeds past the mid 80’s with one of these already.

Bill Mazzoni (TABOO) has taken a bold lead and built a Scism Cat with diesels. It received a great deal of both exposure and acceptance at the Miami boat show. It also performed well right out of the box and has a lot of potential in it.

A lot of boat manufacturers are interested in the idea but naturally want someone else to figure out the work involved first so that they can sell the customer on other’s success. It would be nice if there were more players in the diesel market. Yanmar has a strangle hold on the performance boats. VOLVO is far too heavy and too slow in the rpm. The CAT 420 needs a serious diet and more power. Cummins needs a cost adjustment and a diet. MAN is supposed to be making an engine that is both competitive to the Yanmar 440 in weight and power.

If the Sweden company can get the GM V8 Isuzu diesel engine reliable, as it is light, short and competitively priced for the U.S. boat market, there could be another player in the market. Same goes for Ford. If they can make these engines with sufficient power 450+ then they would fit (fall) into the market trend. (GM and FORD need more attention to this market segment) The 6 cylinder engines are as Super Termoli has pointed out, are very long in length and this makes the engine room space an issue for installations on the smaller boats. A drive package is easy to make, but even then the engine is longer!

I have to agree that a GM diesel V8 would be a good thing because it would fit right in the space originally intended for gasoline BB motors. If guys in Sweden can have over 400hp out of it, then I believe someone like Mercury could do the same and make it reliable given the resources they have. Those diesel V8s are good engines, the main problem being the turbo-charging system. Problems arise on 400+ versions which have twin turbos and for some reason, twin turbo-charging is a thing that never really got solved properly on diesel engines. Seatek's racing versions also have twin turbos and they have also been giving us hell. Even MTU's 12V2000 1500hp and 16V2000 1800/2000hp engines have this aspect of their design as a weak link. Otherwise, Swedes have a 300hp version which is single turbo and works just fine. However, if they increase the capacity of their engines (only 6.5 liters now) they might be able to get over 400hp without resorting to twin turbos.

Yanmar is going to become an even bigger player in that market. The 6LY2-STP 440hp motor is going to be fitted with an electronic management system and reportedly, it will make around 480hp. This will most likely happen next year. There are also plans to push it up to over 500hp.

Volkwagen may become a major player too. Smaller engines up to 180hp are already available in Europe, based on their 4 and 6 cylinder compact blocks. Which leaves us hoping that they will marinize the engine they have in their Touareg and Phaeton models. It's a 5 liter V10 producing 313hp as it is now but pushing the displacement up could easily yield over 400hp. It is a twin-turbo but let's hope VW did their homework.

In general, with the rise of high-performance automotive diesels like VW, Mercedes, BMW I hope something will trickle down to our offshore world. Because when you look at their cars, diesel models often outperform their gas counterparts, like a 530d vs. a 528 or 530i for example...

Super - Volvo was clearly at the limits of the DP-S and DP-G drives with the 300 hp engines, which is why the new DP-H/DP-R drive is here. The fact that they have rated it for commercial duty implies a pretty high level of confidence from a conservative company. There will be a pair of D6350/DPR's in a 20,000 lb/40' performance cruiser this summer, so we'll see how the package deals with the real world. (Here's hoping for the best.) This same manufacturer has complained about popping a lot of Bravos behind the Merc diesels in their boats. (The Volvo test boat will be an interesting apple-to-apples test.) Until Mercury does something about their drive situation, they're stuck at 300-310 hp.

Rik - The KAD300/DP Volvos are rated at 3800 rpm/1270 lbs including drive. The Yanmar/Bravo 3 is rated at 3800 rpm/1138, so I really don't see that much difference - just 132 lbs.

Volvo or Mercury - it doesn't really matter, as long as somebody gets a grip on an easily installed, reliable, and affordable package. (That pretty much leaves #6's out.....) :) That way, we (the consumers) all win.

I have been following and thinking about this for some time and I really think that with the price of fuel and some of the advances being made with diesel engines that the conventional boat market could really use this option.

As for offshore boats I would think that people would be real interested in a boat with diesel power capable of high 70's to high 80's performance. Maybe mated to some surface drives smissions mounted in boxes outside the boat to give more room in the engine compartment and an overall affordable package. With the weight reductions that have been happening with diesels I know I would be interested.

I like my polished blowers and BB as much as the next guy but if I could run the same speed with twice the fuel economy and 4-10x the reliability it makes sense.

Can I get a JACOBS Brake on it :D ? Rag's :D

I have a lot of customers with the KAMD Volvo engines in CANADA that were originally in front of a Volvo leg. Simply put it doesn’t sound like its going to work for anything but small light boats. The Konrad drive grenades under the Yanmar 440’s and I feel their design is stronger than the Volvo’s. Even the Bmax’s won’t live behind the Yanmar’s which are a high revving engine themselves.

Another point is that the 3800 rpm diesel makes no torque and is only 300 hp. This is practical for small lighter boats, nothing big and truly nothing fast. Hence the Bravo lives with this package as well.

BMW makes a marine diesel engine. Have seen a few of them in boats. Yamaha makes a diesel engine but they push it towards the “Middle East” only for some reason.

We have neglected Mercedes, well if we were Brazilian we would be crying about that. They have been making a diesel engine for years for the Brazilian market. 600 ish and so hp engines. Probably make something smaller as well but information is very limited outside their markets.

The GM engine is relying in a “Whipple” blower for boost rather than a turbo. Maybe this is the key or their Achilles heal? They have plans for more than 500 hp out of this same engine. If they can get it reliable, then as far as installations, they have the ticket.

Yanmar is set to introduce their new 4 valve head really soon which is suppose to bump the power to 500ish. Well it will have to be that much after one changes the injection pump settings. The electronic management might do away with the injection pump mod but hey, who’s going to be the first to chip their diesel boat?

I can see a pantera now with a diesel. Hw about the sound though?

What about multispeed trannies, not just 2 speed how about 3 speed ?

Curtis

I agree with Rik 100%. It may be that we have reached the limit of conventional shiftable outdrive design with about 700 to 800 pounds of torque. Given my experience with Volvo drives, I am not convinced the new one is going to be any more reliable, commercially rated or not. Bear in mind that they are going to be used and are primarily intended for exactly what their test bench is: a 20 000lb cruiser which will do 40 mph. Put this package into something like a 388 Hustler and suddenly, with 700hp, you'll be in high 60s for sure. Compared to 40s, this kind of speed places much more stress on the drive. Keep in mind that a 38 of this kind will weigh less than half of that cruiser's weight and that a combined effect of this reduced weight and more speed will be more launching off waves. Landings are particularly hard on drives and historically (perhaps because Volvo is so conservative) Volvo DP drives have not been designed with violent use in mind. Finally, a customer who buys a 40' cruiser is generally much milder-mannered than an offshore performance person. They are not tempted to slam the throttle all the way down, accelerate to the max, etc. So my point is, Volvo DP drives have been designed for their main market: cruisers. And I believe they will be reliable for this kind of purpose. However, for anything above 60 mph, whether they are commercially-rated or not, this drive will spell trouble.

Rik, I've had BMWs in my first boat. It was a 1987 Sunseeker XPS 34' with a pair of 200hp motors. Good motors but crap drives. Had both of them replaced within 250 hours and those motors were only 180 PSHP. Then they associated themselves with Mercury for a while and then sold their business to Mercury. I think this was the starting point of Mercury's D-Tronics but I've never heard about BMW in marine business since. Apart from Victory Team class 2 race boats which used the 4.4-liter V8 block. Did I miss anything?

As for Yamaha, they are available in Europe and some Sunseeker Superhawk 48s were made with triple 260hp Yamahas but they never really took off. I didn't hear anything bad about them, they just never caught on.

The bottom line is, I think, that we have to think completely outside the box. We can't keep our standard outdrives, our standard engine compartments, etc. if we're to use innovative and non-standard engines. We have to go for the whole deal and accept that if we're to use diesels, we need slightly bigger boats and/or slightly bigger engine compartments and surface drives. It's costly, it will take time to get used to it but trust me, once you go there, you'll never come back. And the more work you invest in that change, the better it gets. Trimax demands extensive modifications of your transom and a lot of work and yes, it is a pain. But imagine a drive at which you can throw anything and you can't break it even if you're trying. I mean, I went over a 30' log that fell off a freighter, damaged my props, but the drive suffered no damage at all!

NO PAIN, NO GAIN

BTW, rtaylor, it will sound like a truck. and smell like one too. you can't have it all but some people like the sound of trucks. however, nobody likes the smell of diesel trucks.

Curtis, are you talking about 2 forward speed, neutral and reverse trannies? If so, it's already here. ZF makes them and they are very good for diesels because the short first speed allows the turbos to kick in faster and it also allows the power to overcome excess weight easier. Once the turbos are on, you can upshift and enjoy another burst of acceleration. It works great with Yanmars, either a 90 or 110-series ZF trannie. 312 for Seateks and 550 for bigger. Infact, that Hustler with four Yanmars has those 2-speeds in it and it will outaccelerate any 35 to 40 boat with 500s or 525s. And it's 23 000 lb dry so it's quite impressive stuff those 2-speed trannies. And 3, 4 and so on forward speeds is just a question of time. Lamborghini has been using them in racing and all cars have them, so why not boats. A single forward speed makes no sense. Imagine if you had only second or third on your car. Not very fun!