big-boss

Does anybody have experience repowering a 35-38ft Cig with a single or double diesel I/O set up? Say two Volvo Peta 285 HPs? Understanding it would have less power: How would it ride? Ride in the rougher stuff? Very much better fuel consumption?
Thanks

SKRAMER

I don't know much about diesel engines. But I would think that with 285hp, its ride wouldn't be that good in rough water. I think it would be going to slow for the hull to do what it was designed to do.. Just my .02

liquid prozac

maybe you should just buy a tugboat

hurleyr

What you gain in MPG will be lost big time in resale. My 2 cents.

big-boss

It's is not about the MPG as much as the crusability of a tug with the look of a cig, that simple. I want to put in at Morro Bay and "drive" to San Francisco than if I don't want to take the water back put it on the trailer and go home. I really haven't found something that would do that, either in the trawler world or the powerboat world. Unless I want to go 6 knotts for two days. I must make it I guess?

HabanaJoe

You won't go fast enough to make the boat right good, it would be a pig. You need twins and you need no less than 400hp each to make that boat run decent.

I've done it on Super Hero 34's & 40's, the boats aren't all that different.

I can get into my opinions on drives and gears etc, but without the Hp your going no where!

big-boss

Thanks again, I am seeing the light and maybe understanding something. The deep Vee Cig style boat needs HP to hoop over the water- wave to wave so to say. What does I guy need on the pacific side of the US to go 40-50 MPH for six to seven hours and not have to pee blood and be able to trailer it as well? Is there even such an animal?
Watching the latest Miami Vice with the new Don Johnson running to Cuba with the hot chick like he was driving to the nearest hotel made me start a quest. Some reasearch later I am finding it ain't that easy! Especially on my side of the world. What do you think?

HabanaJoe

big-boss,

Now that I know what you want to do here are some facts.

Firstly, PIG was a harsh word, the boat will ride good just not up on the water as intended. It will ride like a center console that goes 40 knots not a wave crusher as people here label them.

Attached is a dyno sheet from an old 380hp Cummins B (look at the date) and it clearly shows the engine making it's designated 380 Hp. This engine came out of a Super Hero 40' patrol boat after Merlin disputed the engines Hp claims. What was funny is Merlin wouldn't let a thrid party run their engines on a dyno - wonder why?

Anyway enough stones thrown - the point is at the bottom you see an area marked as "actual hp used". That means based on measurements while in the boat, boost, fuel flow, air temp etc that is the amount of Hp that is actually trasmitted to the propeller. I'll answer why so little so no one asks - without a 2 speed trans or a slipper trans you can't get the boat on plane easy. Remember this is almost 18 years ago, full mechanical engines, single turbo, VGT's didn't exist and you had to ventilate the prop to get on plane. You can also see by the rpm's your clearly running in droop which is cutting power as well. You just couldn't get all the hp to the water and still have mid-range cruising speed. I'll refernce our Buzzi boats again, great top end speed couldn't stay on plane below 50 mph - race boat not pleasure boat used all the Hp available.

Those days were different than today!!!!

With only an average of 320Hp available in a 40' deep vee hull with lead ballast to weight about 17,000 lbs to simulate crew/weapon loads this boat ran just above the intended speed of 55 mph.

Your wanting to run at 50 mph for 6-7 hours is nothing even 20 years ago - today it is simple.

That patrol boat had Arneson drives, 1.15:1 gears, 4 blade cleavers and a single speed non-slip trans. You take a 35' Cig put in the 480 hp B's, the same drives a 2 speed with a slight over-drive and you'll be into the 80's. The boat will cruise for hundreds of hours at 60 mph and never miss a beat - promise!!!

Your first question: the twin 285 Hp diesels in a 35' probalbly won't go much more than 50's so cruising near 50 is out.

Fuel ecomony, if it takes 500 hp total to go 50 mph in a 35 cig than at .35 lb/hp you burn about 25 gals an hour (I don't the Hp number to be true but the fuel burn is close)

Joe Gere

big-boss

Thanks HabanaJoe, very informative. It also makes since with what I am picking up at the "Boat Design" forum.
What is tha 'Super Hero 40'" you refer to? Thanks again

HabanaJoe

Super Hero/Hawaii was a brand, we brought the Midnight Express molds and played with them a little to make a 40'. So in essence they are derived from something that Aronow did at one time or another making it very close to a older Cigarette.