Mast partner

Update: here is Jari's "fork" design for the mast-partner:

The forward hole could be made a bit bigger so a 4mm acetal-rod with a small central hole for the jib-sheet will fit. There could be an M3 or M4 threaded hole added for the mast-ram, and finally some holes for a U-shaped bent wire which forms a deck-eye through which the no3 jib is sheeted.

Here's the glassfiber version I was first thinking about:

The way we mould the deck and hull in one go we don't get an overhanging foredeck which would support the mast. One solution is this kind of "mast partner" which is glued/bolted to the foredeck and provides sideways support for the mast. If the slot is made say 16 mm wide the mast will need a sleeve of metal/plastic that fits this 16 mm slot accurately. There is room for a ca 18-19 mm diameter thumbwheel(red) on the mast ram.

Here's a photo of a SAILSetc 10R (or M?) which uses this idea:

3 thoughts on “Mast partner”

  1. Inspired by this post, I made my own mast partner design and machined it from
    aluminium at this evening. It's a simple "Fork" design. I think it looks pretty
    good, at least on grey boat! If you come to the workshop tomorrow
    you can take pictures of it, I did not have my camera with me today.


    I have machined nine balsa cores for rudders during this week. First balsacore rudder
    with carbon axle was laminated yesterday and 5 hours post cure for it was made today.

  2. If we machine this from Alu, can we make it fit the 6mm wide and 8mm deep slot accurately? Can the same alu-part have an M4 thread length-wise for the mast-ram?

    The no3 jib needs to be sheeted from just where the foredeck starts. Can we attach a U-shaped wire for the no3 sheeting-point?


  3. I measured deck slot dimensions from the hull we had laminated and I did get pretty good fit. No problem to glue and bolt machined alu part to the slot.

    Part can have M3 or M4 thread for mast-ram. There are thumbwheels with M3 thread and 12 mm wheel diameter at the workshop. It is a perfect fit for that part. Also U- shaped wire could be possible to put into this part.

    I don't yet have long enough twist drills to drill those holes for M3 threads. Regular jobber drills from hardware store are too short for this job. Have to buy some 95 mm long 2.5 mm drills at the next week.

    It took about two hours to design, program and machine that first prototype part from aluminium. It's so fast process to make these or slightly modified versions from aluminium that I think it is the right manufacturing method. Glassfiber lamination is so slow process that at these days nobody has time to do it 🙂

    Can you publish Pikanto deck layout drawing to this blog?


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