ratman

i plan to go for it and buy another offshore boat in the next 8 to 10 months, i was looking at the huge diesel thread on diesels in offshore boats. because im also looking at over 5 bucks a gallon for regular fuel here in colombia. 6.30 for hi test, diesel is about 30% less than regular.

i wonder about maint say on a 850 hp blower engine vs a 850 hp big ci n/a engine. which engine is lower maint, and will go more time being run hard?, and which would burn less fuel, or does it take x amount of fuel to make 800hp no matter what engine configuration you're running?

i love airing it out and running in big water and the diesel dont seem like they like to be throttled. and set up seems critical, 2 speed trans, huge up front costs, or heaven forbid it doesnt run/perform well. i see where some diesel boats wont plane much below 50/55 mph!

if i go the n/a route, i can build my own engines and sort them out jetting wise, im a little apprehensive on blower motors here in so. america as there is no one running that type of power in the country to my knowledge... i do not think there is a dyno i the country where i could run a blown bbc.

if i bought a 41 apache with fresh power i would just ship it down and run it til i puked an engine, then ebay all the blower stuff and run big n/a motors.

diesels seem to work very well in even bigger boats, but i dont was to go to a 47 or 50 and have to run trips for good top end,,, but twin diesel fuel efficiency is pretty awesome! what do you guys think?

you know of any offshore boats in the 38 to 43 ft range successfully running hard with diesels? thx, rm

hogie roll

I do Diesel engine development for my day job, and ill be the first to tell you, you can't beat the power to weight ratio of tuned up gas engines. Diesels are usually all iron, need a trans, and will still make half the power or less of a good good gas motor that they weigh close to.

ratman

thats why im thinking big cube tq monster with a single dominator, i would think a big stroker motor will out live and be less maint than a smaller blower engine....

unless i an find somebody running twin diesels in a 40ish footer that really performs well i think im going with 632 850 hp a side... in a 41 apache.

the larger boats that are running trip diesels like bob the builders new ride are the bomb... but thats out of my price range...

obrien

I have been involved in multiple performance diesel applications and it really comes down to the kind of performance you are looking for. My boss at Mastry engine had a 39 nor tech with 480 yanmars and arneson asd 8 drives was capable of 80+ mph with a full cabin and a generator. The old 42 fountain lightning with 440 yanmars and asd 8s would run upper 80's. Neither of these boats needed multi speed transmissions. From what we have found on several of the boats we did, the diesel applications ran better with larger diameter props

ratman

at what speed do they fall off plane? is it tough getting them over the hump and onto plane?

Tborisch

Sunny Leonard 1005 ci an engine.. 2000 hp

ratman

http://www.ultrastreet.net/engines/632_bigdawg.php

i like this 900hp 632, single 4 bbl

ratman

but that engine makes diesels look inexpensive....

Young Performance

At 850 hp, you would be better served using a Whipple on a decent sized cubic inch engine rather than going NA. You could build a 598 c.i. engine, put a Whipple on top, run only a few psi of boost, run it on 87 octane and have it live for a VERY long time. You really don't even have to go that big with the C.I.. I only said 598 since you would have a ton left on the table if you ever wanted more. That would outlive an NA engine making over 1.3 hp/ci. I'm not saying that it can't be done because it certainly can. I'm just saying that the SC engine would outlive the NA engine, especially with a carb. With a carb, you have no protection that efi affords you. You would have to run 93 octane with the NA engine. I'm not sure what the fuel is like there, but if you didn't get 93 and thought you were, then you are in for a bad day if you go and beat on it. There is no reason that a 598 with a Whipple making 850-900 hp won't live for 350-400 without a problem. We have done it before.

Good luck with whatever way you choose to go.
Eddie

12meter joe

Stop being a sissy and get these

http://www.offshoreonly.com/classifi...o55908-en.html