Hello - I am looking to re-power a 1983 50' Gibson hb. It currently has two 4cyl 138HP volvo "anchors". The boat is in Boston and I'd like to install engines have the hp to get me from marina to marina in the Massachusetts bay quickly if the weather kicks up as well as not have to fight the windage of the boat when maneuvering around the marina. I've got call into the manufacturer but documentation is scarce. Question: will replacing the two 600lb 4cyls with two 900lb 6 cyls be too much weight or pressure on the transom? Does this sound like a good idea? If I new the cruising or top speed of the boat when healthy I'd have a better idea of the necessity of replacing the existing engines but I know nothing. Any help appreciated. I'm happy to be a new member of this forum. Thanks, Jim

What is the model of your Gibson? Is it a Lazy Cruize, Standard, Executive??? If your bottom is reasonably clean and you dont have the boat loaded too bad, you should get 8 - 10 mph out of the Volvos. Note: These little Volvos have a lot of heart, are trouble free and might surprise you.

Have you contacted Gibson?

It is a Lazy Cruize. The bottom will be clean when I repair the existing volvos (not turned over in 8+ yrs) or repower with 6 cyls. There is a good chance the boat will be operating with an above average weight load. I've contacted Gibson but haven't heard anything yet. I guess they're little slow these days because they were hit by a tornado in April.

The boat seems to have an oversized engine compartment for the exisiting engines. I figured instead of taking the time to repair them (if repairable) I'd replace them with something more capable of moving a 50' houseboat around the Atlantic coastline vs. a relatively calm lake or river. I was hoping to do some minor cruising this summer.

Thanks

This boat was designed for V8 vee drives. The small motors were installed for owners that had no need for speed and wanted a large boat that was cheap to operate. This it does very well.

IMHO you should restore it to it's original configuration. If it doesnt have enough performance it would be cheaper to sell it and purchase a boat that fits your requirements than to modify this one.

If you do decide to modify this one, bigger 6s are not the way to go. They might get you a couple of miles an hour but won't get you on top. Find a wreck with 454 V8 vee drive set ups and go that way.

BTW running around offshore in a houseboat is not the safest deal in the world no matter how much power you have available.

OLD Houseboater - I really appreciate the information you are providing me; I'm new to houseboats.

My cruising intentions consist of maybe 5-6 trips in the summer around the harbor, up the charles river, and along the Mass coast to a destination on Cape Cod bay side of Cape Cod (not Atlantic side) - never more than a couple miles from shore. Do you think this sounds unwise?

I know this boat had a vee drive model that year but assumed a conversion from i/o to vee was not an option if it wasn't designed with the vee in mind. However, I do need to replace the outdrives anyway (boat was not taken care of - no zincs for years). What do you think.

I want to keep this boat; I really like the _style_ and internal layout.

Thanks,

jim

Your in salt water so vee drives would be my preference. However Volvo outdrives live better in salt water than others so look for a pair of Volvo units with V8s FRESH WATER COOLED. 350 BLOCKS MINIMUM.  Should get you 14/16 MPH and probably won't plane but would achieve most of your _object_ives.