Compression post issue Islander 28
I totally agree with Stillraining. Forget shims, cut out the failed plywood and replace with new wood. I used a short maple plank from an offcuts bin at Rocklers, about $5. On my 1978 I28 I found no rot in the plywood under the compression post but it had distorted badly. Maybe the plywood got wet a few times, maybe the wood wasn't strong enough to begin with and maybe the fact that the foot of the compression post does not sit wholly on the bearer beam contributed. Two cautionary notes: (a) don't jack up the mast too much or you could break the fibreglass tabs holding the bulkhead to the hull and (b) if you're replacing, not shimming, make sure you have some very very solid temporary mast supports - you don't want them giving way! Do not rely on one upright timber balanced on a bottlejack, that would be asking for trouble. I used 6"x2" timbers from Home Depot.