Outboard to Inboard Conversion

Discussion in 'Outboards' started by NewGuy8519, Jun 19, 2014.

  1. NewGuy8519
    Joined: Jun 2014
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Private

    NewGuy8519 New Member

    I'm new to this forum, this is actually my first post. So I should probably start by saying I know very very little about boats, I work on cars for a living and I'm sure with my automotive knowledge I should be able to pick up on boat electricals and drive-train components fairly quick. So to my questions, I recently got a 16 foot 1971 Tri Hull for free, needless to say it needs a lot of work. It currently has a non-running outboard engine and I would like to convert it to an inboard sbc engine, could anyone give me some help or advice on the subject? A good start would be if it's possible to do this conversion? I know I would have to change some parts on the engine (starter distributor carb etc.) And if I can would I have to do fiberglass work to the rear of the boat? Sorry in advance if any of my questions are dumb or should be obvious but like I said I know very little about boats, this is kind of an exciting new project for me and I'm diving in head first.
    Thanks for any help.
     
  2. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,035, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Hello, my first thought is the boat is probably too small for the engine you have in mind. What kind of drive are you thinking of, a shaft set-up ?
     
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Yeah, a small block in a 16' boat is a really tight fit. It might be possible to install one as an outdrive, but you'll still be pretty cramped. Then there's the weight issue. Replacing a 200 - 250 pound outboard with a 1,000 pound small block, transmission and shaft is just a huge jump, so the boat needs to be large enough to accept this additional burden and still have capacity for crew, fuel, batteries and a safety margin. Besides, you don't want a straight shaft setup in a little boat, trust me. The outboard or a small outdrive is the way to go.
     
  4. NewGuy8519
    Joined: Jun 2014
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Private

    NewGuy8519 New Member

    Thanks a lot for the replies. I'm not going for anything to extravagant with the boat, really the only reason I want to swap to inboard is my personal opinion that it has a little cleaner smoother of a look to the overall boat and using an engine I'm already familiar with could be helpful in the long run. The engine I was thinking of using is a 305 sbc, their very easy to find and they usually push a little under 200 hp nothing to special. It wouldn't be a big deal to switch my plans a little and use a V6 or even an inline 6 engine if that would make a better fit and make the finished job any better? With any of those engines and an outdrive set up could it still just be to much weight for my boat? Being a little cramped isn't a big deal I just don't want the boat to be on the verge of sinking or having so much weight it crawls at full throttle. It would probably average 4 passengers coming to roughly 750 pounds.
    Thanks again.
     
  5. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    An in line six is worse in regard to length than a V8. Any inboard will make for very tight quarters inside a boat of that size. Post a picture of the boat, but I doubt you'll be able to install an inboard, unless it's a really small (garden tractor size) setup.
     

  6. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,035, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Get four big-bellied good ol' boys to stand at the back of the boat, and see how it sits in the water. That is what your V8 will do to it !
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.