Displacement hull?

[dmilamj]

Originally Posted by FAST FRED

But for the dreamer , simple concepts can help decide what is and is Not suitable.

FF

Oh I agree, I cut and pasted your rules of thumb into a spreadsheet...cause I am definitely a simple dreamer.

It was more a chance to drop a silly pun than anything else....

[powerabout]

The only thing about gas v diesel and safety is in OZ if you ask an insurance company which power is used in boats that go up in flames they will always say diesel.
Why, the boats usually have huge engines in small compartments so the engine box/room is way hotter. Many dont have water cooled turbos just covers over them, if an oil line or injector line cracks you have instant bonfire as the spontaneous combustion temp of diesel and oil is way lower than the exhaust temp.
Remember the old fill your motor bike up and drip fuel on the the hot exhaust..never goes up as gas needs about 750f to go up...
Now if you add a spark to the game its a different story....

[powerabout]

The rule of thumb that works (ed) in the US was that diesels were never really cost efficiant for the average user as gas engines were so cheap the cheaper fuel cost never factored in unless you were a commercial operator.
I thinks thats why the US never really had small marinised diesels.
What US made diesel engine under 100hp is there for a boat?
No market for a truck either

[Submarine Tom]

Perkins, I believe, are US made are they not?

[Ad Hoc]

No, Perkins is UK company
http://www.perkins.com/home

[Fanie]

Compromises compromises compromises. Can't you guys just come up with a solid answer for once

Some pretty neat answers there, I could not think of anything clever to add, and if Richard Apex has nothing to add then you know it is REALLY good

I have never been a diesel fan, but then I cannot imagine a big boat with a petrol engine.

[powerabout]

A boat is a compromise isnt it?

Perkins was owned by US GM from late 80's not sure now

[daiquiri]

Originally Posted by Fanie

Compromises compromises compromises.

That could be a perfect title for the first lesson in any course in engineering.

[FAST FRED]

"What US made diesel engine under 100hp is there for a boat?
No market for a truck either"

However anyone wanting a great US diesel can simply install an International DT 360 or Int DT 466.

These are a over 100hp rated , but are really cheap at any truck wreckers, have std SAE bell housings (Twin Disc can be fitted) and are really cheap to keep.

AS truck, or skool bus engines they take light loading and prolong ideling better than an industrial engine.
Either would do 5-6gph worth of work for a long time!! As you should expect from 1300lbs of engine.

The same engines come in mechanical injection and electric ,boat use would be safer with the older mechanical setup.

A complete rebuild kit is on sale a couple of times a year at about $700.00 US so its not like Volvo or Yanmar with gold plated parts. And the International dealers actually stock parts! Unlike V or Y who fly them in at YOUR expense.

FF

[powerabout]

Fast Fred
Sound good, I have always like IH engines.
Who makes the marinising kits?
Regards
Powerabout

[powerabout]

Perkins is ownd by CAT I see...
Cat also owns MAK in Germany so it has quiet a range of engines now.
And perkins had worked with the Japanese for years so...
parts made in Japan,( with iron ore from Australia smelted with Australian Gas?) assembled in the UK, painted yellow and sold in the USA?

[FAST FRED]

Who makes the marinising kits?

YOU DO!

Getting the flexplate and marrying the SAE2 bellhousing to a Twin Disc is all off the shelf., at the tranny store.

The only question then is what to do with cooling and the exhaust.

On a slow (non plaining ) boat keel cooling is the answer , as it has all the advantages .Can even be home made from 1 1/2 water pipe .

Se were left with the exhaust , dry stack with 2 inline truck mufflers would be first choice , cheap and quiet."Hospital Grade Silencers" is quieter but heavy 200lbs and expensive new. Used??

A sea water pump (belt or electric driven ) with an electric backup would handle cooling the exhaust enough to use rubber hose to the transom.

The truck exhaust manifold would have custom blankets made to keep the exhaust heat out of the engine room,

OR there are wet exhaust manifolds made , but at about $3000 are sorta pri$y for what you gain.

FF