Islander 30 MKII compression post substructure

[GNI]

Thanks for these pictures and video! I've got to get back to the boat to see what I can match up. Did you have notch out the post at the top for the mast wiring or does it come through next to the post?

[tonykeel]

Hi GNI,
As I recall, all that was needed was a small notch out of the bulkhead. The compression post (the existing and new one i installed) did not need a notch for the wiring. The compression post has a dado (?) groove running its entire length and the bulkhead slips into this notch. At the top, the bulkhead has a small piece missing to allow the wiring to snake through a hole in the mast step and down the side of the compression post, hidden behind a piece of teak furring.

Incidentally, where the mast light a radio cables penetrate the step leaves a vulnerable location for water to get in. The mast produces condensation inside even if water does not get in they any other way, and this water collects in the mast step. There were two (small) weeping holes in the mast step that were supposed to let the water run onto the deck out the side of the mast step collar but the water could still go down the wiring hole and into the cabin, and indeed it had been. I welded a small pipe nipple over the hole in the mast step where the wiring goes through so that water cannot go through the wiring hole and into the cabin. I also drilled out the weeping holes a bit to let the water out easier. All of this was at the advice of a very wise boat building who was helping me with my overhaul. I would not have thought of that myself.

[tonykeel]

Originally Posted by harbin2

TonyKeel
I recently replaced my standing rigging and upon tensioning, I realized I am having the same problem as you with my compression post and base. I'd appreciate any photos or additional information you have on the work you have done since I'm now considering the same. I have a Bahama 30 which, I believe has a larger compression post but I don't think Islander solved the problem buy just beefing up the post.
Thanks, Harbin2

Hi Harbin2;
Yes I think that would not solve the problem. After we sawed the sole open this exposed the teak block that the sole sits on. But the sole is a two layer fibreglass structure at that point, with an air space in between that sags over time. After we chizzzzzeled (i don't know how to spell that) out the teak block to see what was going on under there, we found about a pound of hard composite bedding compound made of some sort of resin and fibre mix. The block had a vee in the bottom that was supposed to sit in the vee of the hull and it was kept in place by this compound. But that stuff had crumbled and shifted a bit adding to the problem Once we got the block out of the way, it was an easy matter of making a flat spot in the vee hull with fibreglass, and then making a larger flat bottom teak block to sit on the new flat surface. This block extends up through the sole and the post sits flat on top of that. I admire it all the time. That fellow from Blaine WA did such nice work.
I hope that helps you some. It sounds hard, but it really wasn't.

[harbin2]

Thanks Tony
Were you going to post some photos of your work?
Here are some I took. Can you shed any light on what I'm seeing, composition of the post and substructure?

Boat is a 1981 Islander 30 Bahama
Post measures 3 ½” x 3 ½” square. It appears to be solid but there is a cap/insert on the aft end near the top that must house something.

Photos
1 – post in center (for orientation)
2 – Shows approximate drop in elevation of the forward end of the sole where the posts rests.
3 – Shows approximate drop in elevation of the entire forward end of the sole.
4 – Underside of sole beneath post. The area in the top, center looks like some kind of repair – I’m not sure.
5 – bottom of bilge leading forward.
6 – top of post (aft end) showing cap approximately 1” wide and 12” in height. Not sure what is under it. There is some wiring running up into the mast at the forward side of the post running from under the headliner into the base of the mast.
7 – mast step (for orientation)
8 – shows concave shape in the deck fiberglass structure

[harbin2]

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