Bulkheads - Fixed or Non fixed ?

[Shacklepin]

Not too long ago a dear friend and I sailed Ebb Tide, my 1982, 367 Cutter, to Cuba and back from Kemah near Galveston in Texas. The return journey from Havana via the Dry Tortugas was exceptional and the most enjoyable sailing I've done in my 40+ years afloat. A broad reach in 18 knot winds built to 40knts after 5 days, with 20ft seas. Ebb Tide handled it like a dream even filling the cockpit on two occasions, however downstairs she screamed like a banshee !! The noise coming from the bulkhead to liner interface. Aft, I have reinforced the cabin roof by installing a couple of compression posts one from the half bulkhead by the Nav desk and another vertually opposite between the corner of the fridge and the roof. These are both screwed and glued and reinforce the rigidity of the hull amidships. The noise was coming from the vebirth bulkhead and the shower bulkhead for and aft.
My thoughts are to inject epoxy into the gaps either side of the bulkhead channel to fix these things n place.
Thoughts please.

[Nereid]

Shacklepin,
Do you have any photos of the gaps?

The only caution I could think of: it may not be effective, and or may put stress/change the stress load path into a component it may not be rated for. With varying thermal expansion (especially with touching a deck with the sun beating down on) that could cause stress too.

Photos?
-I

[Shacklepin]

Hi Neried,
I'll get some picture neit time I'm there.

[SV Azimuth]

I know the last response here was almost two years ago, but were you ever able to grab photos of your work to prevent the creaking? We have similar symptoms and I've been brainstorming ways to make sure the bulkheads are secure with the headliner to minimize movement and rub.

Any thoughts about how to access the top of the bulkheads around the head and behind the sink? Would injecting thickened epoxy suffice or could there be a better way to secure the two surfaces?

Cheers

[Shacklepin]

Hi there SV Azimuth,
After a lot of deliberation and consultation with highly knowledgeable salts a decision was made to get used to the groaning. It takes a bit of getting used to but one does in fact it becomes quite comforting.
As it couldn't be determined as to whether the bulkheads were supposed to be able to move in their slots or not, several opinions were voiced about generating stiff points an hence stress points where none are supposed to be. I have stiffened up the central cabin by adding floor to ceiling posts which eliminated a lot of noise at the aft to central area it is only the V birth bulkhead that groans and, as I said previously, I'm happy it does. My option was to run an angle grinder into the gap and inject a thick epoxy filler. But never did. Please tell me your thoughts. Regards.

[P69]

That bulkhead is structural  along the vertical part where it is glassed to the hull, but along the top, in that groove, it's just loose, like the rest of the partitions. Remember, Pearson built the interior, then lowered the deck. Those grooves are just guides for the tops of the bulkheads to slip into and stay  in place.


Where they are glassed to the hull, they help the hull hold its shape.  Even if you were to inject epoxy or even through bolt the bulkhead through that groove, it will unlikely contribute to any strength or form a hard spot because that groove that holds the top of the  bulkhead is in the liner, which is mostly loose inside the boat across the overhead and not fastened to the underside of the deck. There are  places where there is a large gap between that liner and the underside of the deck where wires are run and there are other places where the deck presses down on the liner. 

Epoxy filler will  probably fall out after a while unless you rough up both the gel coat surface and the slick plywood surface. You'll also need to be pretty creative in how you are going to keep the epoxy in place until it cures because it's relatively heavy and finds any way to run down hill.  Even if you fill the bap, you might not lessen the noise because most of the noise is likely originating  where the end grain of the plywood interface with the fiberglass liner at the top edge of the bulkhead. It doesn't take much movement end grand wood to squeak on fiberglass.

Instead of injecting epoxy, which will likely just run out as gravity pulls it down before it cures, it might be better to lay up some light cloth  with epoxy resin  and wedge it in the gap, pressing it against the roughed-up gel coat and the plywood,  but that will make a mess to cleanup.

[S/V AMITY]

Or spray some dry lube up in there to kill the noise.

[SV Azimuth]

Thanks for the responses—

Shacklepin, where did you put your floor to ceiling support columns? I've thought about putting one at the corner of the galley counter, at the back right corner of the icebox and extending up to the corner of that storage area mounted to the "roof". Seems like a good hand hold as well especially under way. I wonder if one could put similar tensioned structural points in the v-berth shelves, potentially at a slight angle, to pull the foredeck down onto the hull. We get a lot of creaking in that area while underway but also while anchored... it's not great for sleep quality!

And thanks for your reply P69, you make good points about the likely futility of injecting thickened epoxy in those areas. I wonder if there's a capable caulk that would, instead of adhering the two pieces, act as a sort of low-friction plastic to quiet the noise from the bulkheads rubbing on the liner as the boat flexes. Maybe something I'll look into.

[S/V AMITY]

  From your description it sounds possibly like some part(s) of the bulkhead structures have popped loose from the hull.  Very minor racking of the entire structure is unavoidable but a hull working to the point of making loud groaning & creaking to my mind calls for a full inspection of all hull tabbing.  In you shoes and with that symptom, I'd explain what's going on to a surveyor and have him track down what's going on.  If it is failed tabbing it is easy to fix.

  One other thing to check is mast rigging.  If it is not tensioned properly it can exert excessive side loads on the coach roof at the mast partners thereby racking the structure.  An easy test to see if this happening is to see if the fit of the closed head & fwd. cabin doors change when tacking to windward.  If you see the air gaps between the closed door frame and the door actively change size, that points to the rig being improperly tuned.   

[SV Azimuth]

S/V Amity — Now that you put it like that, I fear something more significant may be occurring. The hull and decks are stiff and this doesn't seem like a water intrusion issue but it sure does creak and groan under way and at anchor.

From the few areas of bulkhead tabbing I know where to observe, they look strong and intact. Do you have any tips on getting to the harder-to-access areas? The liner seems to present an issue because the way it's designed prevents me from viewing that contact area with the bulkheads. Curious if you or anyone here have beaten that without making serious cuts in the headliner.

Checking the mast rigging in the manner that you suggested is good advice. I'll take a gander at the head door frame on each tack next time we go out (forward cabin door was removed by the previous owner so I don't have that point of reference). We did get a rig inspection recently though it was to determine the age and condition of the standing rigging in regards to getting it replaced, rather to check specifically for correct tension. I'd like to think it's in a good place but I'm far from an expert.

[S/V AMITY]

  You can make a virtual head door by taping two strings in an "X" pattern from top to bottom across the door opening.  Bottom port to top stbd. and top port to bottom stbd.  Any movement will be seen by one of the strings slackening and the other tightening alternately as the boat rocks.  If they both tighten together, skip to my last paragraph.  Both tightening at the same time means the cabin top is lifting.

  To see some of the hull/bulkhead tabbing, go inside the head locker behind the sink and remove the aft interior vertical plywood wall... It should be held in by some small screws around the perimeter.  Once you have that opened up you'll be able to see where the stbd. bulkhead tabs to the hull.   On the port side... if memory serves, you should be able to see some tabbing either inside the locker above the shelf where a heater is sometimes mounted or inside the hanging locker.  Some plywood disassembly might be needed.

  A handy weapon you might want to consider is a fiber optic scope.  With the scope's flexible neck you can peer into otherwise inaccessible areas without doing any disassembly or (God forbid) demolition.

  My sense is the mast has something to do with the problem because rocking gently on the hook puts practically no stress on the hull... except potentially where the mast penetrates the cabin top.  A mast is a powerful lever and can cause all sorts of mischief if it has an opportunity to move.

  Last thing... but maybe the first thing to check is the tension rod immediately aft of the mast in the cabin.  Its purpose is to keep the cabin top from pumping up when strain is applied to the port and stbd. shrouds & uppers.  That rod should not be sloppy loose.  If you find it is loose, there is an adjustment nut on the end of it at the mast step.  Rod should be tightened just enough to take out any slop but should not be tightened hard.  Consider it as a preventer.  Its sole purpose is to prevent the cabin top from lifting when the shrouds & uppers are under strain.  If for some unholy reason the rod is missing that might very well be the problem right there.  If it is, you owe me a cold one.  Cheers!

[P69]

Azimuth,

Here is a post describing the two poles I installed (one at galley corner and one at nav desk). they are 1 1/4" dia schedule 40 pipe, perfect for grabbing and in good spots for when moving around.

https://pearson365.com/forum/index.php?topic=1868.msg9749#msg9749

[SVJourney]

@SV Amity,  That was one helluva write up.  My hat's off to you Sir!

[S/V AMITY]

Nice work P69!

[SV Azimuth]

Thank you S/V Amity for that thorough write up and to P69 for those detailed photos and description. Both help immensely!

I will take what I can get as far as ideas and expertise, and it's especially great that we're talking about the same boat. I plan to check the tabbing where accessible and the mast tension rod as soon as I'm able, and to run your string and door gap method next time we're under way.

Does anyone know if:
1. The P365 has a tendency for delamination in the deck? Could the wood core and fiberglass top and bottom layers be rubbing within the deck itself? Is this even possible?

2. There is a gap between the deck and the headliner that would/could cause rubbing while each flex from movement, stress, or temperature?