Originally Posted by npronpro
I'm thinking of replacing my wooden compression post with an aluminum jack pole (king post). How does one obtain/make up an aluminum jack pole and put it in?
Before you can have an aluminum jack-post fabricated, very careful measurements will be required. To do so, the mast needs to be removed so that you can take the measurements without any deflection in the deck. If there are any repairs which need to be made to the cabin top, or to the bearing at the keelson, these repairs should also be made before the measurements are taken. Then very carefully measurements need to be taken of the length of the post and the angles of the top and bottom plate in both fore and aft, and laterally. It might make sense to make up an accurate mock-up in wood to check your work, be certain that you can install it, and then you could give the mock-up to the fabricator as a pattern.
Depending on the size of the post and the thickness of the bearing plate, the connection between the post and the top and bottom bearing plates may need gussets to keep the plate from bending. These should be planned so that you are still able to get adequate bolting for the post. Lastly, you will want to either seal the post at the top and bottom or else have drains at the bottom if you chose to pass wires or otherwise have openings in the post.
Alternatively, you may also want to make all of the necessary repairs to the boat and then have the fabricator measure and build the post, making the fabricator responsible for producing the right product.