Latest News: Forums Technical Outboard Bracket Mounting Position

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  • #3961
    Anonymous
    Inactive

    Hi All
    I know there has been lots of discussions on the position to mount outboard brackets, I would welcome some guidance, and am adding a photo for some clarity.
    I have a GRP Mk II, and have (as per previous threads) elected to remove the buoyancy compartment, to replace in some form later.

    Now that I have removed this, I can see the area on the inside of the transom which has the re-enforcement.

    The common guidance seems to be to keep the outboard bracket and the rudder as far away from each other as possible, whilst ensuring that some re-enforcement is used on the inside of the transom.

    From previous posts, people suggest the centre of the mount to be 400mm from the centre of the rudder pintles.

    However, the re-enforced area stretches to only 300mm from the centre line of the rudder pintles.

    That being the case, I could add some re-enforcement, but appreciate this would be over a smaller ‘working area’ ie not so far to spread the load.

    Here is a picture:

    the dotted red line shows the outline of the re-enforced area.
    The vertical black dashed line shows the centre of the rudder pintles.
    You can see the measurement from centre to edge of re-enforcement is 300mm.

    And the area left to the side of the re-enforcement (which is in the 400mm zone) is relatively small.
    I would welcome advice on whether I ‘simply’ glass in another piece of wood beside the re-enforced area, in this case on the left as we face it, and whether this piece of wood – if it takes up most of the space – is likely to be spread the load sufficiently to hold the weight and stresses of an outboard (in this case a 2.3hp Honda, circa 12-13kg)

    Or – do I say glass in one piece of wood, then glass another larger piece of wood on top to cover both the existing and new wood, ie spread the load?
    From a practical view this is slightly less preferable because I would need to really smooth down the existing re-enforced area, but I could certainly do it.

    Finally, the bracket I am fitting is – I believe – a similar style to one which many people use, having a removable arm fitting into a fixed bracket:

    So – the bottom line question:
    What type of re-enforcement should I be aiming for?
    Or – am I making this too complicated, and actually I should just use the existing re-enforcement and be careful with the rudder…?

    I would welcome your thoughts and opinions.

    Thanks

    Jon

    #8329

    Jon

    I faced exactly the same situation a few months ago when fitting my bracket and dont mind admitting being very aprehensive of hanging quite a substantial weight off the transom – the bracket was much heavier than I was expecting (we too have Honda 2.3). I can tell you what I did and confirm that after quite a bit of engine use everything seems to be ok, but of course up to you to make your own final decision.

    I firstly cut a triangular piece of marine ply to fit in the gap outboard of the reinforced area. I drilled through the transom (after long agonising over the final location) and this piece of ply. I then appplied marine silicon to the back of the shoe and glue to the back of the ply pad and then assembled. The glue I used is called Webbfix, a rapid setting polyurethane adhesive, salt water resistant, suitable for marine use. The other main advantage I saw in this glue is that it is an expanding one, clearly the inside of the transom is not as flat as the ply so anything that expands to take into account the uneveness has to be an advantage. I let the glue of the first pad dry and then, as you mentioned, cut a second pad which overlaps the reinforced area. It was simply a case of undoing the nuts on the inside, glueing up the second pad and replacing and re-tightening the nuts. Then for good measure I added as much glue as I could around the edge of the second pad. This glue comes in a standard 310ml cartridge for a mastic gun.

    So far so good – the transom is still in one piece and we are really enjoying the benefits of having the outboard on a braket. Hope that is of some help and best of luck.

    Jonathan
    W2312

    #8340
    Anonymous
    Inactive

    Thanks Jonathan, what you suggest makes perfect sense, I have now installed it – and yes, my choice to do it this way!!

    I have hung the outboard on the back with the boat on the trailer, SEEMS all fine, I now need to go and put the boat in the water and try it out.

    Thanks for your help.

    Jon

    #8373
    tempest51
    Member

    Jonathan,

    Could you please give a more specific name for the webbfix product, as they have many types?

    Regards,

    Tempest51

    #8376
    #8377
    tempest51
    Member

    Thanks Jonathan,

    Tempest51

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