Mr. Demeanor
Cost and weight. Even a pair of little Yanmar 6 cylinder turbo diesels will set you back more than a pair of new Merc 525hps.
Gary

Actually ---look at the big performance boats there's quite a few that have come out with Yanmar options in the last couple of years. Before that the biggest problem was getting the power to weight ratio in line. There's 38 cigs out there with 3208 cats v-8's but they're just too damn heavy for the power they put out. The yanmars are only like 250 lbs more than a dressed BBC, and can run close to WOT all day long and still pass some fuel pumps at 75mph.
Yes they are expensive but a 420 hp diesel isn't that different in price compared to what you would buy from Merc that could give you that kind of performance. And maybe in 30 years when these diesels are being rebuilt by shops all over the country and there are all kind of used/ and aftermarket parts like there are for the BBC maybe they will be cheaper-- I know they will require alot less maintenance!
Mcollinstn--You're right we won't see any diesel vettes, but in a pleasure/ performance boat it's not about accelerating quickly, rather it's fast and steady wins the day! For me at least
I know if I was buying a 47 ft fountain or similar I'd be eyeing up the diesels---

Oh hell just get the turbines

Hey, I LOVE diesels.
I'll never consider buying a boat over 15,000 pounds without them.

If I lived on the Florida coast, I would be riding in a 42 plus foot performance hull with hotrodded diesels and surface drives.

Performance, economy, the ability to run at 85% all day long, beefy transmissions to harness the torque, and a bunch of stout stainless steel sticking out behind the boat that won't corrode off of it or blow the floors out of the pinion gears every time you fly off a big roller.

Question#1: (Why no supercharged diesels.) We have addressed this. Turbos are more efficient.

Question#2: (Why aren't more lightweight highpower diesels used in performance boats?) Because you do, indeed, give up performance over a comparably-rated gas motor. You also have stink, fuel that foams out all over your hands when you go to the pumps, and soot. They also add, on the average, $40,000 to the cost of a twin engined boat, and can't be bolted to an outdrive, which forces the installation to a more unconventional (read expensive) surfacing drive. They are also very long and force boatmakers to scrimp on interior cockpit size to fit them in. THIS, I believe, is the strongest set of reasons why we don't see more of them.

That, and the fact that there are more people capable of buying a 26 foot boat with gas power than a 45 foot boat with twin diesel surface drive power.

Not to say they aren't out there, just that they are a tiny minority of the whole of the performance boating pie.

I agree totally!!!

Here is a v hull with a diesel, this vent 85mph aprox, it has a sea tek diesel 650hp, the boat is 36feet.

Another pic

last one

WOW -- That looks like a pretty trick set-up, do you have any info on that single engined wonder boat?? 85ish is moving for a single 36 fter. What kinda drive is that and what the hose coming into the top of it??
I wonder what it would be like docking though--probably not extrememly manouverable...

What are the details on that set-up.
The beam looks very narrow.
Do you know what hull and drive that is?

I've heard horror stories about Seateks.
Running on the ragged edge, from the info I received.

If you've got em, I've heard that you shouldn't expect them to last more than 250 hours between major teardowns.

Course this is not experience talking, only repeating hearsay.