i just hauled out today and noticed the same problem with my 1990.
If you look at the design drawings at the website on the first page (a feature article) it appears that the void between the strut bolting flange to hull surface is filled with epoxy compound. My first assumption, until I research further, is that the compound has just failed a bit and it is not major glass hull material failure. It still might be wise to grind out and refill though. Let me know what you come up with.

briang and Jamie, and other new members listening in,

May I respectfully suggest that you provide more information about yourselves and your boat. There are several ways to do this on the forum, such as in your profile, and/or in the automatic signature that you can set up for every post you make; just take a look around and see how others are doing this. I imagine you're worried about spam, but honestly, that has not been a problem so long as you don't put your email in plain view...instead use a system like "johndoe(at)yahoo(dot)com" if it is ever necessary to mention an email address. I've been participating in this forum for at least 6 years, and have never been bothered by spam.

It would be courteous as well as beneficial for members to provide their full name, their boat's name, hull number and year of mfr, where it is based, and what waters you sail. This will benefit you in several ways. First, it makes your presence here more personal to other C36 owners who are offering to assist a fellow owner; Second, it allows a natural "sorting" of any technical questions that arise...folks who have or are knowledgeable about Mk I series will more readily respond if the question comes from or is more applicable to a mk I, etc; Third, when we know you might be sharing the same marina or the same home port, it sometimes allows face-to-face help to be offered. Who knows, someday you might be anchored in the same bay with another C36, you'll recognize the boat name, dinghy over, and make the acquaintance of a really nice person.

Welcome Aboard. We welcome your questions...and when we're in need and you have the answer, we for sure welcome that also.

Briang,
Looking at your picture I think the marterial around the strut has started to fail and this should be an easy fix. The strut is bolted to the inside of the hull and the exterior has filler and glass around it to the shape of the hull. If the strut is loose, then you'll have to tighten it before replacing the material around the strut. Look at the article on the home page about replacing a strut. The article is about a MK I, but the method of filling in the strut area on the outside is the same. You will notice that the 2 owners used different filler materials.

I hope this helps,

We had small cracks on our strut hull # 1437 mk11 1995. I have looked at the struts on all the 36's around our area and every one without exception has shown some small cracks around the area where the strut joins the hull.
After snugging up the 4 nuts on the strut, I built up the area with glass and epoxy and faired down each side of the strut. It made quite a difference and since doing this I haven't had any further cracks.