Aluminum inboard

Discussion in 'Inboards' started by Lonestarholiday, May 28, 2015.

  1. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    I have a1963 lone star holliday 16' deep v aluminum boat currently 55hp outboard wanting to convert to direct drive inboard need to know what motor tranny set up I need. Haven't seen aluminum inboard before atleast in Oklahoma
     
  2. gonzo
    Joined: Aug 2002
    Posts: 15,498
    Likes: 1,039, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    There will be several problems to solve. The first, and most important is the center of gravity change and the thrust alignment with it. The thrust won't be adjustable like with the trim of an outboard, so whatever you install, you will be stuck with. Second, finding an inboard of 50-60 HP in gas will be virtually impossible. You will have to find an engine of that power and custom fabricate exhausts manifolds, etc to make it work and be legal. Transmission for that power are available, usually are used in sailboats. What is the reason to try to change to an inboard? It hardly seem to be worth putting so much money and time into a boat that old. You could by a fairly new boat with an inboard for less.
     
  3. nimblemotors
    Joined: Jun 2009
    Posts: 244
    Likes: 3, Points: 0, Legacy Rep: 4
    Location: Sacramento

    nimblemotors Senior Member

  4. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    Thanks for the reply the boat is rated for a 75 hp max Outboard. Thout if I could find a doner boat maybe a ski nautique maybe a 283 sbc or an inline six I need top speed of about 25 to 30 would be nice. Trying to make an affordable wake surf boat which I need the prop to be under the boat not just for safety but for the way the water comes off the back of the boat using gates and wedges to create a wake that can be surfed like a 100k boat
     
  5. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    Nice video ive thout about the sea doo conversion a lot other than jet drives don't deliver the wake desired for surfing
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    You'll never get a SBC shoehorned into a 16' tinny. The typical trans/engine combo is over 4' long and weighs about 800 pounds. A marine 283 is rated at 185 HP, which is 2 1/2 times what the boat is capable of tolerating, so forget about it, besides, who would put a large journal SBC in a boat anyway, unless it was an antique deserving of this treatment. Besides in 1963, the 327 would have been the choice, though still a large journal SBC, a much better one, especially with 202's on it.

    A six would be longer, though a bit narrower than a SBC, but again you just don't have the room in a 16' boat, once you toss a trans and shaft on it's butt. A 4 cylinder on a V drive is a possibility, but still a cockpit eating contrivance.

    Before plopping down some money on an engine/trans setup, do some measuring and figure out how much space you have, then do a weight study, to see what you're working with. A typical SBC, velvet drive, rudder, wheel and shaft arrangement will be a half a ton worth of gear. You could knock a few hundred pounds of this with an aluminum LS, but she'd still be way over powered.
     
  7. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    i don't believe in to much power I need torque and the weight problem is no problem I need the weight the boat can handle it how would I go about finding center of gravity
     
  8. gonzo
    Joined: Aug 2002
    Posts: 15,498
    Likes: 1,039, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You may not believe in too much power, but it doesn't change the laws of physics. Too much power and weight will break the boat. Also, weight is one of the most critical parameters. If you add a lot of weight, the boat will sit low and need more power for the same speed. It will also need more power for the same acceleration. Further, the center of gravity will be to far back and with the skier pulling the bow up, it is likely to perform worse. There are thousands, maybe millions, of people skying with outboard powerboats with no problem.
     
  9. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    With the amount of power a SBC will provide, you'll very quickly run smack into a longitudinal stability issue, which can kill you, if she's upset significantly enough. This happens with racers every year and I lost a buddy a few years ago, for the same reason. Again, your tinny just can't support a SBC straight shaft setup, even if you could shoehorn it in there. You don't have the hull volume for it, fuel, batteries and crew, not to mention the boat's weight itself, so give up this idea. If you want an inboard, you might find an old tractor motor, bolt a tranny to it and rig up a shaft. Given the amount of engineering necessary to make this type of arrangement practical and reliable, you'd be best advised to look at the other options.
     
  10. SaltOntheBrain
    Joined: Feb 2007
    Posts: 123
    Likes: 7, Points: 18, Legacy Rep: 87
    Location: crosbyton, TX

    SaltOntheBrain Senior Member

    You guys aren't listening to him.
    He wants the huge wake of a wakeboard boat ( not speed ), which I don't believe he'll ever get with a 16' tin boat.
    PAR and Gonzo are right, though. Probably a waste of money, time, and a perfectly good boat to try to modify what you have.
    He needs a boat that will run about 18-20 knots right at hump speed to get a big wake for jumping and tricks. They do this with water ballast, wings, and big heavy boats.
    If you put enough weight and power in your little skiff, you won't have much freeboard and it will break. Somewhere.
    LF
     
  11. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    Hull volume batteries crew? I have batteries a crew, tig welder and enough aluminum to build two boats I've put 2000 lbs in this boat before 800 in back 500 midship and 700 in the bow so when you've never seen the boat before how strong can you say it really is without seeing the structure but there's no need for weight anymore with wedges and gates. This is not a wakeboard boat wake surfing is done from directly behind boat to about 10 feet out there's not even a reason for a huge wake it's all about the rip and curl of the wave the way the prop spins the water off the back of the boat a small wave with the right shape is better than a big wave. The speed to wake surf is about 10 to 15 mph max with the top boat speed of 25 to 30 mph is the fatest I would ever want to go so an average a 18 to 20mph cruseing around I will direct drive this boat maybe with a smaller motor shaft drive atv motor inline 4, 302, 4.3 who knows.this boat is about torque not speed not about speed I will have to do more research and post more pics and videos to explain thanks for the replys
     
  12. SaltOntheBrain
    Joined: Feb 2007
    Posts: 123
    Likes: 7, Points: 18, Legacy Rep: 87
    Location: crosbyton, TX

    SaltOntheBrain Senior Member

    You told us what boat you have.
    A thin hulled, riveted 1963 Lone Star.
    Using a gate to pull the hull harder into the water will approximate the stresses on the hull of filling it with weight. Not to mention the stress of the gate on your transom.
    I spent years doing repairs to aluminum boats. I see a lot of cracks in your future.
    Low speeds like you want are better than high speed, but I still find it hard to believe you can build engine beds elaborate enough to evenly spread the torque to the hull, and put a wedge on that transom and not end up with cracks all over the place.
    You might get a season or two out of it, though. After that, you'll be chasing cracks from metal fatigue.
    Maybe by then you'll have a new hull built you can swap all your hardware over to.
    If that's part of your plan, I see nothing wrong with it.
    LF
     
  13. Lonestarholiday
    Joined: May 2015
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Lake Eufaula Oklahoma

    Lonestarholiday Junior Member

    I put this stuff called glue vit on the inside and out side of the hull trying to seal the rivets 2 gallons hopefully I can find a bigger motor than my 55 evinrude I've also thout about mounting an outboard mid ship i know that sail boats do this and was wondering what yall think of it is it possible to seal the motor to the boat without having a well in the middle of the boat I know that it would have to have a rudder setup to steer thanks for all the replys I know most of you think I'm nuts but I can't not customize anything it has to be different I will post more pics thanks for the help
     
  14. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The boat could have an outboard mounted in a well, though it'll be aft of midship, if you expect any real performance from her. There's no way of doing this without some sort of well. You'll also need to add quite a bit of reinforcement to the hull, just to support the weight and transfer the loads to her bottom. You wouldn't need a rudder, the nature of an outboard's vectored thrust will do a far better job of it.

    Why are you trying to reinvent the wheel? All you want is a wake boat, which is easy enough with an outboard and some shape modifiers, which is pretty much all this little boat can handle. These require a considerable amount of HP to make them effective, but considering the speeds you're targeting, a whole lot cheaper than cutting up your boat in hopes you'll get lucky with some contrivance.
     

  15. gonzo
    Joined: Aug 2002
    Posts: 15,498
    Likes: 1,039, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    If the rivets are leaking, that means that there is structural damage. The rivets are stretched and the holes enlarged. Not a good candidate for a power increase.
     
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.