TARP POSTS

  For the two sections of the lifting mast that could be used as posts for stringing up a tarp...

  After looking at the renderings again, I'd put sleeves for the post ends either in the outside corner where the beams meet the windward hull, or in sockets in the beams themselves a few inches from the windward hull (provided this doesn't get in the way of the telescoping beams when the boat is collapsed).  Maybe with a little round screw-down access hatch to cover the hole when not in use.

  That way the tarp can cover a about half the windward cabin, including the outside seats.  Also, the ridge lines for the tarp will get a bit closer together as they approach the masts, making for a slightly funky design that will end up looking intentional.  Since they will be strong enough to lift the main mast, they'll be strong enough to handle the ridge line tension without having to run guy lines down to the windward hull.

  The posts would end up being a bit tall if the ridge lines were run to their tops, but there's no reason why the lines couldn't be fastened at any height.  Higher for more room and ventilation, lower for more shade or weather protection.  Or make the mast in four sections -- shorter for the tarp use, plus easier to get in and out of the hull.

  Or...


INSTRUMENTATION MAST FOR ANTENNA, WIND METER, AND COMPASS

  One, two, or even all three sections could be mounted/stored on the windward hull as a VHF and wind instrumentation mast.  The 23' height would be less ideal than if the antennas and instruments were on the schooner mast heads, but it might be a more reliable solution if the main masts are rotating masts -- no coax cables to worry about twisting.  Perhaps its socket fits into the interior post that supports the cabin top and the big table.

  It also makes the instruments more accessible, as well as opening up the door to a mast that rotates 180 degrees when shunting, allowing for a wind meter and compass that face "forward". 

  Though that still sounds like a lot of work unless it can be reliably automated.  Plus it puts us back to having a shared antenna for the VHF and AIS uses.  But since most boats do that, it's not the end of the world. 

        - Mike

 

If not, build 5. 5th is the gin pole and a spare?

  Nice use of materials, pieces, and budget!

  Though since I'm personally sold on a lifting mast instead of a gin pole, I'm not sure it would work for me.

If we assume two piece masts, could they be 4 clones? Like do they HAVE to be top/bottom?

  I think they might have to be top and bottom.  There's much more stress at the bottom, so it needs to be thicker/wider/heavier.  But we don't want the extra weight up high:

    - It's extra weight and cost
    - It adds to heeling moment
    - It helps to have thinner/flexible tops to bend in gusts


  Another limiting factor is what we can actually fit into the leeward hull and then remove.  A 25' half mast would probably need to be fastened outside the hull.

  That said, even the three-part lifting mast in 8'-6" sections might not go in and out of the hatches on the leeward hull as they're currently positioned. 

  But I'm reasonably confident something of that length could be feasible.

         - Mike 

a8b7k57g@protonmail.com [harryproa] wrote on 4/14/2020 12:35 AM:

 

Hey Mike;

If you are trailering, don't you need two piece masts?

And, I think, robs carbon masts are about as cheap as you can get?

If we assume two piece masts, could they be 4 clones? Like do they HAVE to be top/bottom?

If not, build 5. 5th is the gin pole and a spare?