Question about outboard power

[PeninsulaPaul]

Hello Everyone,

I am restoring a 36' Whitcraft Coastal Cruiser. The engine, rudder and drive were stolen a few years back (long story) so instead of replacing them at GREAT expense, I opted to convert to outboards. I am working with Jeff at Outboard Exchange in Port Angeles, WA. GREAT guy, has taught me tons about my boat.

He has never steered me wrong (pardon the pun) but I do have a question. He is installing twin Mercs at 115hp a piece, they are older but with a fresh rebuild. They have hte extended shaft so they don't have the cavitation (sp/) problem some conversions do (I've been told). But with a normal load of a few people, what kind of speed could I be looking at for that kind of HP? Just to let you know it does have a VHull which is unusual for a houseboat type boat.

I will post pictures later but wanted to know if anyone could garner a guess who might be familiar with my boat.

 

[rodbolt]

Re: Question about outboard power

be prepared to eat rowboat wakes.
twin F225 yamaha on a 33 grady white stuggles to maintain planeing speeds when the engines are less than 4200 RPM.
you will most likly have to have a prop shop custom make a set of props to allow the engines to make it to the operating range.
a pair of 260 HP small blocks may push that hull at about 35 MPH or so.
most inboard boats dont have the transom strength to hold a bracket and bracket selection is critical as most inboard transoms dont have the correct transom angle to mount the bracket, the extra angle needed MUST be made into the bracket, typically 13 to 16 *.
thats also why most inboard to outboard conversions fail and have cavitation issues.

 

[ezmobee]

Re: Question about outboard power

Yeah that sounds INCREDIBLY underpowered.

 

[Chris1956]

Re: Question about outboard power

Is that 36 footer a planing hull? Coastal Cruiser sounds like a displacement hull.

 

[Huron Angler]

Re: Question about outboard power

The hull speed for that rig might only be around 8kts, and two 115's might get around 5kts, enough to tool around a bit.

Are the Mercs 25" XL shafts or normal 20" long shafts?

Some photos of the boat would help folks give you better info on what to expect.

 

[PeninsulaPaul]

Re: Question about outboard power

Just found this on the original powerplant.

Engine Information:
This boat may have come with the following or other engines :
(In the interest of safety, never exceed the manufacturer's maximum horsepower rating for your boat.)
2-155 hp inboard
225 hp inboard

Here is the boat's picture.

http://www.facebook.com/photo.php?pid=6041391&l=11c005656c&id=834948573