Help with outboard bracket design

Discussion in 'Boat Design' started by savagescout, Oct 29, 2010.

  1. savagescout
    Joined: Jun 2009
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    Location: australia

    savagescout Junior Member

    Hello,

    I am going through the process of restoring a savage 23 foot half cabin (Australian built hull).

    It’s from the 70’s vintage and the current hull looks like this:

    [​IMG]

    I am wanting to modernise the hull by changing the nose of the deck and also converting the hull from an inboard to an outboard/dual outboard design.

    I have photoshopped the design I want to follow and this is it:

    [​IMG]

    The question I have is in relation to the outboard bracket/pod that I want to add. I was wondering whether the bracket should follow the shape of the bottom like this:

    [​IMG]

    Or whether the bracket should be raised about 1-2 inches above the keel line, like this:

    [​IMG]

    I would really appreciate peoples opinions on this.

    Looking forward to your thoughts.

    Nick.
     
  2. WickedGood

    WickedGood Guest

    Looks like your gotta take a traditional Classic Hull and turn it into a Blob Boat.

    Extending the transom to mount a pair of outboards would be nice; However I would leave the smart lines of the original boat.

    Do add at least a 4 ft dive platform between the engines and the boat and make a full transom with large scuppers. If you have to have a door you can put in a door. Gheeze. ( I dont like doors. but if you do make it open outwards)

    A full hardtop without that Blob thiny in your picture would keep with the clean looks and be stronger; both emotionally and physically.

    I would say you have a diamond in the rough there. Maybe after a few years of working on it and 70 or 80 thousand in engines and materials you will have quiet a boat. Oh.. Yea, You may want to sandblast that trailer and weld on some supports and galvinize dip it and maybe a new axcel and bearings and tires , winch and lights and it will work fine.


    There is a REason people GIVE AWAY FREE Boats like that. Might want to think about it before you have to pay to have it disposed of.
     
  3. tom28571
    Joined: Dec 2001
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    tom28571 Senior Member

    You can certainly do what you propose but, along with Wicked, I think the original is a far far better looking boat. The add-on top is a little awkward on the existing boat.

    One big outboard is much less expensive than two and modern outboards are much less failure prone than an IO of any vintage. Twins are rarely more reliable than a single. Work out the balance/buoyancy equation to see how far aft the new power should go and make the extension to fit that. It may be that there will be too much buoyancy and a transom mount or a bracket with less immersion is in order.

    In the end, it is easy to sink more money and effort in a rebuild than searching for a more suitable boat in the first place.
     
  4. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Twins are rarely more reliable than a single ? How did you talk yourself into that ? I suppose it is true if you are happy to have other people towing you in when the inevitable happens if you go out often enough.
     
  5. tom28571
    Joined: Dec 2001
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    tom28571 Senior Member

    Most twin engine installations have a single fuel supply and a single battery system. Most problems with modern engines occur in one or the other of these. Mechanical problems are getting pretty rare and those that do happen usually give fair warning. A single outboard and a small kicker with a separate fuel supply is a more reliable power system than twin outboards.

    You asked.
     
  6. EgliVincent
    Joined: Sep 2010
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    Location: Camas, WA

    EgliVincent Junior Member

    Hey Savage Scout, I understand where you're coming from in wanting to modernize the look of your boat. Key is, you gotta do it on the cheap (both labor and time). Like others mentioned already, your proposal is basically 2/3 of the work of making plugs for a whole new boat. Here's my 2 cents: Bolt a nice gill bracket off the transom and hang a single outboard, make accommodations for a kicker motor if you desire the redundancy. Pull the small windows in the cuddy section and fill back out the holes. Find some newer contemporary windows and cut them back. Pull the windshield and rework it and the top as you like. This will still be a good amount of work but at least you're not tearing into the general structure of the boat. Once you're done with that you'll probably even question why the effort was put in. For me its a nice classic looking boat, I'd keep with the spirit of it and polish it up, modernize the power and be out on the water months sooner!
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    No great drama to have separate battery and fuel. Kickers are OK most of the time, but tend to be useless or unmanageable in bad sea conditions. The real problem with twins is efficiency, particularly if you are hoping to have the ability to plane on one motor, you then need to under-prop and that means more fuel, and you use more anyway with twins. But the security and peace of mind factor tips the balance for a lot of people.
     
  8. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    Why not put a pod (or two ) on the back this will mean for every 6 inches you move the engines back you can lift them 2 inches....so a typical 18inch long pod would put the motors 6 inches higher out of harmes way ...the bottom of the pod does not follow the line of the V hull but is flat and above the water when on the plane.....have a look at the pod on a stabicraft say a 556 ....get some made up in aluminium and bolt them on ..with a deck between if you like
     

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  9. Typhoon
    Joined: Mar 2009
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    Typhoon Senior Member

    Buy a bracket, reinforce the transom, paint the boat and enjoy owning a very attractive boat as it is.
    I'd run a large single outboard, a 200 will be plenty, a 250 would be icing on the cake.
    What you propose to do will cost tens of thousands to do PROPERLY and not look like total garbage.

    Regards, Andrew.
     
  10. pistnbroke
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    pistnbroke I try

    I agree trying to glass new to old poly is a disaster ...get a pod/bracket
     
  11. tom28571
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    tom28571 Senior Member

    You are correct that a lot of people have that opinion. A lot of people think otherwise too. It seems to be different depending on where you live. Probably peer pressure at work.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    Running a barred inlet, or operating in remote areas favours the twin installation. Don't want "kickers" when needing to stay with fast moving swells, or expect tows a long way from civilization. Independence is a good policy in most facets of life. When a tricky bar is the only way home, I really think twins are de rigeur.
     
  13. tom28571
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    tom28571 Senior Member

    I'm tired of the argument and since you insist, I proclaim you the winner.
     
  14. Submarine Tom

    Submarine Tom Previous Member

    I have run thousands of commercial hours on twins and single OB's and only ever had one fail on me, bottom end gears spun. In rescue boats, I'm all for twins but that is for reasons other than reliability, more about durability and damage. Today, there is no need for twins (OB's) in recreation and perhaps not even commercial. You are far better off to spend the money on preventative maintenance than on another OB.

    Kind of ironic your handle is "Mr. Efficiency"... twins are not.

    -Tom
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Tell me something i don't know, Tom(s). Of course they are not efficient, but in certain circumstances, as I mentioned earlier, common sense compels their use. Would you expect some other poor sucker to tow you in over a breaking bar if there was no alternative to getting back in the same way you left ? Putting other people's lives and property at risk to get me out of the do-do isn't my thing. Anyone who tells me there is no place for twin installations hasn't had a big enough fright yet.
     
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