Junk inboard/outboard repower with outboard?

[rlager22]

I have a 1988 Fairbanks 28' Sportfisher. It has twin Mercruiser 470's with alpha one outdrives. The boat is kept in saltwater and has not been hauled out in 3 years. One engine is frozen, the other runs but the leg is in need of maintenance soon. Hauling out is expensive in Hawaii, $1000 or so, and I was thinking to haul, remove outdrives, seal holes, and put on an outboard. I know it will not be doing its original 27knts or maybe not even the 7knts it was doing with one engine, any suggestions? I'm happy with a 5 or 6 knot boat. Has swim platform, teleflex steering all good for outdrives. Thank you very much for suggestions.

[CDK]

The transom will not have the proper shape for an outboard, so the best way to proceed is make a support that is bolted to it. And you probably have to modify the swim platform as well.

[pistnbroke]

A 15 deg angle is standard for the transom or the pod you intend to fit ...how many HP are you proposing to use

[mydauphin]

a 28' foot sport fisher will need at least 75 hp to push it, and probably 400hp minimally to get it on plane. The problem is boat was design for inboards not outboards. I would go with something like rebuilding drives and engines. as best cheapest option. Believe it or not it can be done on the boat while in the water. Get yourself and old hydrohoist type device and jack the rear out of the water. There are companys that will take your old drive and exchange or you can rebuild them yourself.

[rlager22]

Thanks for the suggestions. I had been planning to use a johnson 50 because it is considerably lighter than the 60-90. Was thinking I may have to re-prop it to get any pull agains the wind and waves but the more I think about it the more it makes sense to keep it inboard. Funny thing is. its working just fine with one inboard, have stripped the other down to the block, so now I have all kinds of spare parts!!! I know it sonds like I'm running a janky operation here but maintaining 2 engines and outdrives in salt life isnt the cheapest thing to do. And I just want to putter out and dive/party. I will look into the hydro hoist idea. At this point I think it makes sense for me to haul out, remove old block and outdrive, plug it. Then overhaul the working outdrive and just run it with one. Thanks fellas, my brain was a hurten yesterday thinking about the direction to go in. Aloha

[dinoa]

If you're content with displacement speeds the power requirement is minimal. One or two small Kubota type diesels may be the answer. You might want to keep both legs in the water to stabilize the boat and keep it from wallowing at low speeds. Kubotas are used to power refrigeration machinery on freezer containers and frigocamions and used ones can be had cheap in this part of the world.

Dino

[pistnbroke]

Stick a 115 hp Yamaha 2 stroke on the back and stop pisssssing about . If you can get it over 15 mph you will be on the plane and power requiements drop....nothing worse than trying to go at a speed between hull speed and planing speed