Hollow areas on coachroof of a 1981 H-33 Cherubini?

[Bob Pullen HC-33 1981]

How is the honeycomb or grid of the coachroof on a 1981 H-33, for anyone who has "peeled back" the deck?
I have noticed some spots which resonate and others don't indicating some might be hollow? Are there stringers with possible hollow spots? Has anyone seen one with the deck off?
Although our deck is plenty stiff, no sagging anywhere, we do have spots of delamination inside the cabin, at the headliner. Most of them have been addressed with the addition of our deck blocks, tackle, garhauer traveller, new clutches, etc...where I have chosen to have them bolted thru (in the prescribed fashion...with epoxy fillings, etc) with starboard backing plates bellow, etc. and plenty of plastic caps to make sure no one gouges their head on the nut. However, I am wondering if I should be considering injecting some filler/epoxy into these hollow sounding spots, and if so, now would be a great time.
Thanks for your ideas and suggestions.
Bob
S/V Seanorita
Yucatan

 

[Lee Thompson]

I've shot some great stuff foam in some of the voids in my cabin its helped with noise .

 

[Bob Pullen HC-33 1981]

Filling hollows on coachdeck / roof of a H-33 Cherubini

I'm thinking more in terms of some adhesion to the headliner and filling any voids from past water intrusion. I want to prevent cutting out any deck, but get some stronger bonding with the inside headliner, in places where I think I hear hollow.
I pulled all the handrails (replacing with stainless)...found the source of the only leak we knew about.
Otherwise, we have drilled out the handrail holes and looked -- found all coach deck areas very dry and sound. I would like to have more bonding between the 2 skins and core, without going to the drastic level of cutting out huge pieces of the deck skin.
Any ideas?
Many thanks
Bob

 

[sandpiper10471]

I had a 79. There were no stringers. Deck was cored with balsa. Where you are, the balsa will rot quickly. Where I was, frost forced the top sheet off the wet core. I suggest in order to have a well found vessel, you cut out the top sheet, dig out the remaining core and reglass. It really isn't that hard of a job.

The headliner isn't attached to the coachroof. When I rebedded fittings with bolts, I drilled one inch holes in the headliner so I could attach the nuts under the deck proper. the holes were later plugged with plastic inserts.

 

[Ed H]

The headliner isn't attached to the coachroof. When I rebedded fittings with bolts, I drilled one inch holes in the headliner so I could attach the nuts under the deck proper. the holes were later plugged with plastic inserts.

Is this true for the 1981 Hunter 33's? Some of my deck hardware is through-bolted and visible in the cabin; I assumed I was looking at the bottom fiberglass layer of the coachroof. Ed H.

 

[Ed Schenck]

Pretty sure all models are the same. Your inside cabin ceiling wraps down and out to the toerails. On top of that goes balsa or plywood. Then the outside cover over that. My own hardware is bolted all the way through with fender washers and locknuts visible inside.

 

[sandpiper10471]

No. The cabin liner is separate from the deck. The deck is a sandwich of glass, balsa, glass on the 33. The 37 has glass, plywood, glass. The liner on the 37 is much closer to the deck than it is on the 33. I think in many areas of the 37 you could through bolt to the liner but on the 33, at least on mine, there could be more than an inch of space between them.

 

[Bob Pullen HC-33 1981]

Many thanks. Yes, the coach roof/deck is cored balsa...in our case very gratefully dry! There are spots of at least an inch of space. All hardware we added (clutch's, turning blocks, garhauer traveller, etc..) is bolted thru as per suggested methodology, with backing plate, fender washers, bolts. Sound and dry there, even if we spend most of the day wet, diving.
We appreciate the help.
Bob

 

[Ed Schenck]

I saved these pictures from somewhere, can't remember but not my boat. You can see the thickness of the sidedecks at least if you look closely at the chainplate.

 

[Ed H]

Now I am really confused... Do I understand that there is/may be up to an inch between the headliner and the coachroof? That means the through-bolted clutch I can see is only supported on the bottom by the headliner!!!! Ed H

 

[Ed Schenck]

No, I don't think so. I think that the one inch space is due to delamination. The boat is built by dropping the inside coach roof(inner liner) on. Then the balsa is laid on with epoxy. Then more wet epoxy and the outside cabin/side decks laid over. At least that is what I have been told. And saw for myself on the newer boats on the Hunter tour.

You could bolt through and see if the headliner compresses. If it does then do as "sandpiper" and cut a one inch hole and have the washer and nut go up against the coring. Then one of those nice caps.

 

[Dalliance]

Hope this doesn't add to the confusion, I can't talk about the 33 or the 37, but my '82 H30 definately has a headliner which is separate from the cabin trunk and deck. The space between them varies from zero along an area about 12 to 18 inches wide down the centerline of the boat to about an inch out near the toe rails. If you have space between the headliner and deck anywhere you are through-bolting, you should fill the gap so you don't crush or deform the headliner.

 

[David in Sandusky]

I'm with Dalliance

On our h27, the cabin overhead "sandwich" is:

A liner that floats below the ceiling. (I've had no problem pinning it to the ceiling while fastening new hardware.

About 1/4 in fiberglass then

The balsa layer then

The top 1/4 in layer of fiberglass.

 

[sandpiper10471]

The photos from Ed. S I do believe are from a 37C which has a plywood block core. The 33 has balsa except where there are raised areas for turning blocks etc. molded in and there you will find plywood, albeit just one thin piece. From what I have read, the 33 has far more space between the liner and the coachroof than the other models. I know mine exceeded an inch in places. Never did figure out just how or where that liner was attached other than at hatches and other openings.

Ed S - If you put your finger up under the side decks near the toerail nuts you can feel the liner where it butts up against the coachroof. Must be glued in there or there would be lots of movement and noise when sailing but it is definitely a different piece of structure.

 

[Bob Pullen HC-33 1981]

Finishing up coach deck / compression post / headliner fix

Finally getting it all put back together.
Yes, at least 1 inch of balsa core (gratefully dry) throughout the deck.
The headliner is not hard attached to the underside of this core throughout. This is now rectified with tons of west epoxy with appropriate additives and all deck hardware being through bolted.
Injected lots of epoxy from above after we took off all the handrails (replacing with custom stainless, through bolted with backing plates and fender washers). Something like 28 holes, all solidly filled.
Injected some into places around mast where I noticed a different resonation when knocking. Filled old original mast wiring holes in the deck taking in lots of epoxy there.
All deck was stiff and no soft spots even before this maintenance haulout so no improvement noticed other than everything sounds a lot more solid. All holes drilled came out dry (we are in the water for the entire year).
Ground out the crack in the forward part of compression post, and found the previous owner had just filled the area with lots of epoxy several years ago, thus preventing the cracked headliner ever from being able to get back level without lots of digging out above the headliner, but below the steel plate the mast base and everything in area bolts onto. See pix.
Compression post also showing evidence of corrosion at the base where it sits in the bilge, stradling a crossmember. Cut the compression post out flush with the crossmember. Removed compression post, had welder build up the corrosion spots (previous owner had put on ground wire with copper rings, causing lots of galvanic action). Installed a steel plate across the top of the crossmember in the bilge, with braces and a casing fitting to hold the bottom of the compression post from slipping.
Put a steel plate with a thin 1/8 piece of hi-density polymer plastic to give it some flex sandwiched over the ground out cracked area at the top.
Tomorrow we re-attach compression post, and let down hyrdraulic jacks inside holding cabin deck up.
Painted bottom today, mast comes back on with new rigging on Sat morning...splash in possibly on Sunday.
Bob
s/v Seanorita

 

[Ed H]

Re: Finishing up coach deck / compression post / headliner f

Bob- So, starting from the outside of the cabin top, it goes Fiberglass-balsa core-headliner?...In post #3 you mentioned "2 skins and the core". Is one of the skins the headliner?.... How about pics of your work with the compression post/bilge/crossmember? Thanks. Ed H

 

[Bob Pullen HC-33 1981]

Wrapping it up

Yes, one of the "skins" I mentioned is the headliner, the other the deck.
We have welded/filled the corrosion at the base of the cut out compression post, slicing the very pitted base until we had solid even core all around. It is square and finished, ready to be reinstalled. Lost about 2/3" once evened out.
Then built up the "crossmember" with west epoxy soaked cut mat strips.
Picture shows the crossmember, just before we laid in the stainless 1/8" bottom plate with the holes in a bed of sealant. Next is the compression post with the 3 parts marked "top" up against the corrected headliner, which is now flat...no buckle, no crack. (see picture just before grinding out last buckle)
The thick black base goes up against a stainless 1/8" plate cut about 1 inch larger than the black base. Then a hi-density hi-tec plastic cut about 1/2" larger still goes against the ground out headliner.
The lateral support plates go on the bottom, once all is firmed up, to prevent the compression post from kicking out in case of rolling over.
We should have the reassembled lot together and installed sometime on Monday...will attach pix when done.
Many thanks again to all
Bob
s/v Seanorita

 

[sandpiper10471]

Re: Wrapping it up

That looks like a nice glass job on the compression post step! Well done. Nice and neat and strong. I remember the step on my 33 was very cracked but I never rebuilt it.

I think if you look again, you will find your deck, top to bottom, to be thick glass, 1" balsa, thin glass, space, liner.

 

[Bob Pullen HC-33 1981]

Re: Wrapping it up

We have taken several plugs at different points, and found your description very accurate. Some variations in thick and thin, and at this point, less space between last layer of glass and headliner.
I have noticed on other owners' pictures how the compression post step had delaminated and cracked from the hull. I guess we have been lucky...it was solid and in one piece to start with.

 

[Ed H]

Re: Wrapping it up

Bob- Thanks for the very informative pics. Looking forward to the rest of the pics...I have some discoloration where the compression post meets the cabin top so I am very interested in your project. Ed H