Transom modification

Hi to all!!
I have an old fibreglass boat that has an old OMC stern drive powered by an inline 6 chey. The motor is dead and costs about $4500 to replace. Boat is too old to spend that kind of money so I thought I would modify the transom to handle an outboard motor rather than inboard. doesn't appear to be any rot at all in the transom or stringers so I think I will be okay with a mod. My question is; how much more thick to I make the transom to handle a 150 hp outboard and, has anyone ever attempted this?
Thanks for your replys in advance.
Still frozen in Canada!!

 

Outboard conversion

Do you have a 150hp outboard on hand or can you get a new one for less than $4500? If so can you get me a dozen?

How do you intend to mount the engine? An outdrive has a closed transom so will you use a bracket? Is there any curvature to the transom because that complicates a bracket installation?

Many small outboards boats use a 1½" core in the transom with the skins making it about 2" finished thickness. The outer skin is usually thicker than the inner.

Post a picture or two if you can.

djs

 

Add another $1,000. or so for the outboard bracket.

 

HI Back,
Thanks for your comments I appreciate them as any bit of info is good.
I plan on filling the hole where the stern drive was and then adding about 1.5 inches to the transom itself from the inside attaching it to the stringers as well as sidewalls and bottom. (plywood and fibreglass of course) There is very little curvature to the transom which makes it little less difficult but still a major job. I plan on opening the transom up to accept an outboard.
Sounds like I should just go out and buy a new boat, but I just love this old tub. She has a nice wide beam and is in very well kept condition with the exception of the engine which is shot.
I have already refinished the exterior of the boat to an all white color from it's original faded red and white.
Now I will try and sell the OMC stern drive as it is still in very nice shape and has caused no problems whatsoever.
ANyway, thanks again and I will post a photo or two of the before and after product as I go.
Jim

 

An Inline 6 Ay... Why Don't You Just Buy A Used I-6 Or Rebuild This One ??? I'm Guessing If You Do It Yourself It Would Cost Less Than $1000.00 U.s. I'd Rather Have An Inboard Any Day Over The Outboard.

 

Love This Old Tub

Also... Are You Absolutly Sure That It's The I-6 Thats No Good ???
Is It Locked Up ? Could The Actual Problem Be In The Stern Drive ?

 

It kind of depends on how much you like this boat and if you like doing large projects. It will take many months ( probably more than a year, maybe 2) to finish it if you are only working on it during your free weekends, you also need a warm dry shop to do it in. An older, good used large outboard will be at least $4,000 plus all of the stuff to rig it. There is no real way of buying all the supplies needed, doing all the work you want and keep the cost low.

 

Hmmmm, not sure about that. That's something that never crossed my mind. How would I know?
Thanks
Jim

 

That is,,how would I determine the stern is locked up?
very good point. Geezzz, I'm starting to have second thoughts about a lot of this now. It's great to have feedback that brings these things to the forefront.
Much appreciated!!

 

Locked Stern Drive ???

WELL JIM, I'M NOT A MECHANIC NOR AM I A BOAT BUILDER BUT I'M CONSTANTLY LEARNING ABOUT BOTH AS I'M WORKING ON A LONG TERM BOAT PROJECT MYSELF, 1 AND HALF YEARS NOW. HOPE TO BE ON THE WATER THIS YEAR AS FOR THE QUESTION AT HAND... WILL THE ENGINE TURN OVER ? CAN YOU TURN THE PROP ? I'VE RECENTLY READ SOMEWHERE THAT A LOT OF PEOPLE MISTAKE A BAD ENGINE FOR A LOCKED UP OR TROUBLESOME STERN DRIVE............

 

Pull the drive and try to rotate the engine.

 

Do You Have To Pull The Drive ???
Won't The Engine Turn Over At All ?
If Not, It Could Very Well Be The Drive Unit.