Converting to outboard

Discussion in 'Boat Design' started by dwleo, Aug 14, 2012.

  1. dwleo
    Joined: Aug 2012
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Canada

    dwleo New Member

    Hi,
    I have a 22' Fibreform that am going to convert from I/O to outboard. The volvo-penta inline 6 has too many very expensive repairs required. I have been looking at various transom brackets that allow the addition of a outboard or two. I am looking at about a 120 hp and was wondering if the Fibreform transom is strong enough to hold this or whether it should be built up some inside?
    Here are some links to manufacturers:
    http://www.rickracers.com/product_info.php?products_id=3093&osCsid=39c9c71cf4e1c267bc616f3e88a6f10c

    http://www.dadmarine.com/modelr0.html

    http://www.hermco.net/brackets.html

    http://www.armstrongnautical.com/brackets.htm
     
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 479, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The bracket manufactures would be your best fall back, but as a rule I/O transoms aren't well suited to these loads, so modifications are made. Typically this amounts to some knees in side the boat to get bracket loads transferred to the bottom.
     
  3. tunnels

    tunnels Previous Member

    22 foot you shoud be looking at single 180 hp as a minimum even up to 200 hp for boat that size !!!dont underpower the boat it will never love you for underpowering it . Motor weights are not much differant so go bigger not smaller .
    Your better to have 180 horses in the stable and just let a few out than to under power and be out with the whip the moment you push it into gear and thrashing them all the time just to get on the plane and if you load it with people planing could never happen !! it will never plane !
    Theres a big selection of out boards in the 150 and over range , you need a bracket with the widest base to spread the load over a wider area and as already mentioned knees and a couple of full width beams all way across one side to the other and the like to transfer the pushing loads inside the hull onto old engine beds or new barers .
    Big motors doing less work ,use less fuel , last longer ,and if you get in a dangerous situation can get you out of trouble quickly just the weight of one out board will be considerably less that all that other scrap metal you been draging around all this time .twins naow the weight shot up and also the exspence of two of everything !!!
    will need to shift the fuel tank/s and if there were diesel block a few holes off !!
    Do you home work and fit a good water separator filter where you can see it and not have to going looking fit bigger fuel lines than are needed . keep you batteries close to the motors and up high not way down in the bilge where they are damp and terminals are constantly corroding !! fit a power off main switch so when you leave 99.9 % of everything id power off !!
    Twin motors, twin batteries and a third one deep cycle as a house battery all able to operate independant yet able to be connected to start a motor with a faulty battery so will need to get a clued up electrics person to sort all that !!!!
    Twins you'ed also need trim tabs to get the best plaining attatude for performance and ride and economy !!
    Remember !!! Fuel one side of you boat and electrics the other they dont mix to well !!, fumes and sparks and your history !!. :eek::(:D:p;).
    Jesus i have a 115 yamaha on my 14 foot semi cabin boat !! sure it flies literilly but it only goes as fast as conditions will allow and it comfortable and on a long cruise fishing for the day runs on the fumes out of the tank just about .
    Getting the best suited prop for the boat and how you us it is very important as well .
     
  4. Frosty

    Frosty Previous Member

    I think 200+ would be more like it.

    When its full of fuel put a caution ribbon around the boat with a sign saying "no smoking beyond this point".
     

  5. tunnels

    tunnels Previous Member

    22 foot you shoud be looking at 150 hp as a minimum even up to 180 hp for boat that size dont underpower the boat it will never love you for underpowering it . Motor weights are not much differant so go bigger .
    Your better to have 180 horses in the stable and just let a few out than to under power and be out with the whip the moment you push it into gear and thrashing them all the time just to get on the plane and if you load it planing could never happen !! it will never plane
    Theres a big selection of out boards in the 150 and over range you need a bracket with the widest base to spread the load over a wider area and as already mentioned knees and the like to transfer the pushing loads inside the hull onto ond engine beds or new barers .
    Big motors doing less work ,use less fuel , last longer ,and if you get in a dangerous situation can get you out of trouble quickly just the weight of the out board will be considerable less that all the other scrap metal you been draging around all this time .will need to shift the fuel tank/s and if there were diesel block a few holes off !!Do you home work and fit a good water separator filter where you can see it and not have to going looking fit bigger fuel lines than are needed . keep you batteries close to the motor and up high not way down in the bilge where they are damp and terminals are constantly corroding !! fit a power off main switch so when you leave 99.9 % of everything id power off !!
    Remember !!! Fuel one side of you boat and electrics the other they dont mix to well fumes and sparks and your history !!. :eek::(:D:p;).
     
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.