Hi, I decided to start a new thread on making a sleeve. This is for one-piece masts that go through the hole in the deck (partners) all the way to the keel. Not for hinged masts. The are earlier posts from Greenlake showing his version. Will link later if no one else does. (edit #2--I have a Dwyer mast in case the profile/section matters.)
First of all, it works! Thanks Greenlake!!! Second, you can make it at home if you are decently handy. It makes a world of difference. I'll provide more measurements if needed. Once installed, it worked perfectly on the first try. It's pretty easy to get the mast up and onto the step without a rope/pulley, but I added a simple rig because lowering was more challenging due to taking backward steps in the cockpit. No pics of the rope/pulley yet but it's super basic with a pulley clipped to the Jib halyard hole on the foreplate and a rope to the mast eye. I put a knot in the rope and cleat that on my cuddy top before lowering. The knot is set so as to allow about a 15-20 degree tilt in the mast which gives you a break to step back while relaxed. Pop the rope off the cleat--you now have enough leverage with the rope to use one hand on mast and one on rope. Easy peasy lowering into your normal height crutch.
I will update more materials info later and provide a tracing of the curvature of the sheet metal. Can I load a pdf somewhere?
Anyway from memory I used 1/4" aluminum plate, 1/16" aluminum sheet metal, a gate hinge and a nylon block instead of wood for the spine of the sleeve.
I bent the sheet metal at home using a galvanized steel pipe, 2-13/64" actual OD. Absolutely perfect pipe size. There's a great youtube video on doing this by putting a bolt in the pipe for leverage. (Edit--oops, the trick is to put a screw through the sheet metal into the pipe to hold it in place. The bolt was a second trick I used because the pipe had a large hole through it from a prior use.) I think I started on the basement concrete floor then used the (open) basement stairs for leverage, but with a helper it would be easier. Once I got to a little less bend than desired, it looked great and the bolts did the rest. I was too lazy put washers against the sheet metal on the first assembly and since the nuts are nylok I figured I would reduce wear on them and add the washers later. I think that 1/16" sheet as recommended by GL is perfect. The fit is not super tight on the mast but the flex allows it to really grab.
I cut the plate with a jigsaw and a wood blade. Maybe not the best choice but about the right tpi.
I REALLY wanted some kind of tunablity feature in the plate angles, so I used bolts (5/16"?) with 3 sets of nylok nuts on each bolt. Kind of wimpy maybe but it was a great way to dial in both dimensions of pitch. Don't forget, your deck may not be as symmetrical from side to side as you think. You could maybe use 2 nuts locked against each other instead of each nylok but I took the quicker way for me. You might consider go up to 3/8" bolts but everything looks fine after about 10 uses. None of this mounting is shown due to my syrup jug cover plate to keep the jib sheets from snagging. I'll pop the hood soon and take a pic.
For bolting the gate hinge to the plate, I used an old ski binding mount trick of just drilling one side hole first. Then bolt that on, align, and mark your other holes. Gate hinges aren't necessarily aligned perfectly.
I'm pretty confident that the mast could be even raised and lowered even with the boat in the water, but obviously only in optimal conditions and hopefully a helper. Thanks again to all who post here and members of the community!
By the way, what is that stuff on the inside of my cuddy??? I hate it. It flakes off a little and makes epoxying anything to the inside a royal pain.
Happy sailing! --Nick.