CD 27 mast compression

[mikebikeboy]

Hi Fred, curious if you were able to take some pics or gather some information from your boat?

[fmueller]

Mike,

I finally had time to post a reply and a link to some pix (Drop Box).

https://www.dropbox.com/sh/hjag22cq2sxv ... OUSya?dl=0

First I'd like to say that even with my nose right into it inches away, I'm not at all sure what I was looking at - so anyone please chime in and correct me if you have better knowledge.

1.jpg). I'm sitting on the head shooting up; v-berth to the left, cabin to the right - a good view of the panel I cut into the headliner so I could manage the wires coming down from my mast.

2.jpg). sitting on the v-berth looking aft and up; another shot of the access panel

3.jpg). Panel removed exposing the barrier strip I put there to manage mast wires. 1 inch hole which runs up to a wire gland beside the mast/mast step on deck, wires continue through a sealed hole at the very bottom of the mast and then up the inside of the mast. In this shot you can observe the bulge of a fore/aft box like structure that is glassed into the deck that has approximately the dimensions of a 2x4 or maybe a little larger and runs approximately from the space between the v-berth bulkhead opening aft to the space between the opening in the cabin bulkhead - a distance of just a few feet, if that. Since the openings are not centered in the boat, this bulge/beam which is centered in the boat is biased toward the port side of the bulkhead openings. The mast is stepped more towards the rear of this bulge.

4.jpg) A closeup of the drilling thru to the underside of the deck gland. The layup/core of the coach roof in this area is very robust - about 1 1/2 inch - glass/plywood/glass as can be seen looking up thru to the underside of the gland. The bulge/box structure projects down below the coach roof under surface an additional 1 1/2 inch perhaps and is heavily glassed in place.

5.jpg) This is the most interesting shot and was very hard to obtain with my cell phone camera. We are looking directly aft across the barrier strip along the port side of the bulge/box with just enough elevation to see over the top of the bulkhead posts into the space between the bottom of the coachroof and the headliner. Over the bulk head post you can see what looks like foam insulation; it is mostly aft of the post actually. It is actually some sort of solidified mastic that perhaps glues the coachroof and headliner together and does not really seem to be there to distribute "load". It is actually quite hard and sharp to the touch - a lot like coral - I have no idea what material it actually is. Maybe epoxy/glass mash ?? It is in many similar positions throughout the boat ... More importantly, there is no lateral beam or support that I could see running port/stbd from the central bulge, and except for this weird stuff (only partly centered over the bulkhead post) no obvious direct connection for distributing mast loading to the bulkhead posts via the coachroof structure. So while the coachroof appears to be well built, and there is a stiffening structure glassed into it fore and aft, I no longer believe the bulkhead posts offer major direct support as built. Luckily in my boat there is no sign of water ingress, but it is impossible for me to know the status or condition of whatever is embedded in "the bulge". All I can really say is that so far I am not having mast support issues.

6.jpg) my cabin looking forward from the companion way

7.jpg) the overhead strip of trim in the cabin bulkhead door opening is not nearly as crowned as the trim strip in the v-berth pass through. But there is nothing actually directly bearing on this strip either so I will not read much into this.

So Mike, here is what I think - I'll guess you might have water damage in your coachroof core, likely just aft of the mast step and your coachroof is unfortunately sagging for that reason. Some pilot holes will tell you pretty quickly - but have you tried tap testing ??


Fred

[csoule13]

Good stuff Fred. Hugely appreciated, and is going to help guide how I tackle that area at some point. Shot #6 is the good stuff.

[mikebikeboy]

Fred, thanks so much for providing the pictures and comments. Picture #5 and your comment really makes sense. I wonder why there is no lateral support going port / starboard to support the center trunk which is so heavily built.

More importantly, there is no lateral beam or support that I could see running port/stbd from the central bulge, and except for this weird stuff (only partly centered over the bulkhead post) no obvious direct connection for distributing mast loading to the bulkhead posts via the coachroof structure. So while the coachroof appears to be well built, and there is a stiffening structure glassed into it fore and aft, I no longer believe the bulkhead posts offer major direct support as built.

The other day I was able to go up to my boat. The last time I was at the boat, I stuffed a couple paper towels up into the existing opening I have in the inner lining under the mast. We've recently had a lot of rain. I opened the wooden covering and found my paper towels completely soaked, not just damp but completely soaked to saturation limit.

I cut away some more of the inner lining and discovered more clues that do indeed point to water damage. The white wire is coming from a hole in the mast boot. The black wires are coming from a deck gland to port of the mast:

removed-some-liner-1.jpg

Here is a look at the other side of the piece of liner I cut out. You can see a small hole someone had drilled, which also went into the underside of the deck. It looks like water has been seeping out of that little hole, bring along with it rust or wood tannins:

removed-some-liner-4.jpg

Looking aft you can see a similar view of the strange tan colored substance and the weird profile of the underside of the deck:

removed-some-liner-2.jpg

Fred, I did try tapping around the deck with a screwdriver. I found quite a variation of tones especially going from regular deck areas to around the mast boot where it's reinforced and much thicker. I didn't hear anything obviously dull, mostly seemed quite sharp and bright tones which I read somewhere is good.

I don't know how to approach this, as there are a lot of different aspects to this, and it's not simply a cosmetic area of the boat.

Mike

[fmueller]

That's unfortunate news Mike ... I think you are going to be faced with the prospect of opening up your cabin top and rebuilding, somehow, what is there (wood core/steel section) it having been compromised by water ingress.

This is beyond my pay grade and maybe some of the other more talented crafts persons who post can comment. Maybe John Stone can chime in. Or anyone who has repaired rotted deck core. I do know that this kind of surgery is completely possible - but I have never done anything like it. I think maybe the toughest aspect is just having the facility and time to be able to do it (boat on the hard / at minimum a covering to work under - if not in a shed).

As far as the structure that actually exists - I made a freehand drawing of what I have concluded but no actual confirmation ...

https://www.dropbox.com/s/llx4sxfcsfn71 ... 7.jpg?dl=0

I used to think the bulkhead posts had some function in supporting the mast compression load but now ,I think we agree, that is not the case. The cabin top is reinforced by some sort of fore/aft steel section which is glassed in and I think also provides an anchor for the step plate bolts. In my drawing I made it a box section, but it may just be a plate - I have no idea really.

edit: I've gone back through CD.org threads and there are mentions of the bulkhead posts being "load bearing" but from being able to see "over" the aft/port bulkhead post (which both Mike and I have done photographically) on our CD 27s - it seems to me that earlier post might have been in error about this assertion.

There is no obvious lateral structure that bears directly or robustly on those bulkhead posts transferring load from the fore/aft steel section. The cabin top is quite robust however (absent water ingress ). At least an inch thick just generally in this area and importantly, it's crowned or dome shaped. Where the steel section is glassed in its not less than three inches I think.

There was a fellow, Bob Perry, who worked at Robinhood Marine in Maine until Director bought it out. He might know exactly what is up there in most of the "pocket" Cape Dories. Maybe chase him down ... if he is still "on the right side of the grass" as my pa used to say.

I think its interesting that on our 27s, at least, the mast appears to be stepped at the aft end of the glassed in steel - while you would expect it to be centered, or that the section would continue aft ... wondering if the sail plan was moved aft after the deck molds had been built.