Creaking cabin bulkhead? Sanity slipping...

[25yearslater]

That bulkhead floats. Dissimilar materials expand and contract at different amounts. There are no screws etc. securing the bulkhead at the top it is just a snug fit in that channel. (Photo 1) It is screwed to the bottom behind the trim piece into a very substantial 'lip' at the head. (Photo 2) There are three screws that fasten to the compression post. It is screwed to the settee from the head area. The settee back is screwed to it and the hanging locker is also screwed to it. In other word there are a pant load of screws. In addition to all of this that sucker is tabbed to the hull both fore and aft. (Photo 4) These are likely concealed behind the hull liner. I left mine uncovered inside the settee back because I saw no reason for it. It makes taking a photo easier too. In short if this thing has moved as you say something very serious is going on. It just isn't likely to move so any additional bracing isn't likely to solve the problem. Look over the photos and let me know what you find.

 

[tfrench]

Beautiful job! Did you put any insulation material in the channel between the wood and the glass? Do you now get any noise underway? I notice that the factory installed a brown insulation material aft between the liner and the galley/engine compartment bulkhead. I talked to a rep at Catalina and he said they glue and fasten their bulkheads in the channels. I'll let you know what I find as i delve into this. There has been a lot of moisture intrusion through the chain plates through the years so I suspect rot. Thanks for the pics and thoughts. Time to order ply, glass, ect. Hope my outcome is same as yours.
Like to talk some time my # is 8054640293.
Thanks,
Tim

 

[tfrench]

Hi Main 89

Wondering how you solved your "talking" bulkheads. I'm just starting mine.

 

[hjoseph]

This may be off topic, but I am curious. I'd like to hear a naval architect weigh in on the extent to which the main bulkhead is structural in a modern fiberglass boat. On the O 28, the middle third of the bulkhead is a door; it goes from top to bottom, completely separating the other two parts of the bulkhead. Thus, there is no transverse continuity or rigidity at all. In addition, the bulkhead is not glassed in or very securely fastened to the hull. It seems to be more of a support for the interior fixings, berths, head, sink cabinet than a necessary part of the hull's structure.

 

[jibes138]

not a NA but what holds up the deck on a keel stepped boat?

 

[Panta Rei]

not a NA but what holds up the deck on a keel stepped boat?

Hi Jibes,
The load on the deck of a boat with a keel stepped mast is upward. A bit surprising but not really if you think about it. As you tighten the shrouds, you are pulling the sides of the hull inward. The deck wants to lift.

 

[Panta Rei]

This may be off topic, but I am curious. I'd like to hear a naval architect weigh in on the extent to which the main bulkhead is structural in a modern fiberglass boat. On the O 28, the middle third of the bulkhead is a door; it goes from top to bottom, completely separating the other two parts of the bulkhead. Thus, there is no transverse continuity or rigidity at all. In addition, the bulkhead is not glassed in or very securely fastened to the hull. It seems to be more of a support for the interior fixings, berths, head, sink cabinet than a necessary part of the hull's structure.

The bulkheads of your boat and any other O'day
or similar sailboat is very much a structural component.
The transverse component is the deck. The bulkhead keeps it from lifting on a keel stepped mast boat or dropping on a deck stepped mast boat. Look at the bulkhead. My guess is that there is some additional trim or a post directly under the mast. That is why the door is off center.
As a rule, you can be sure anything that looks like a bulkhead is absolutely necessary.
(

 

[jibes138]

are you sure?

Hi Jibes,
The load on the deck of a boat with a keel stepped mast is upward. A bit surprising but not really if you think about it. As you tighten the shrouds, you are pulling the sides of the hull inward. The deck wants to lift.

One thought is a couple of big fat guys standing by the mast might put a downward force on the deck, or maybe a load of 30 inches of snow in the winter. Say the mast is removed for winter storage and people are walking around on the deck shovelling snow off of her? If the upper shrouds are mounted to the bulkhead Im not sure they are pulling sideways on the hull but they are pulling upwards on the pan attachment at the bottom of the bulkhead and pushing up on the top attachment? On the O'Day the lower shrouds tie into the pan near the water line so those loads are likely trying to squeeze in the sides of the boat. It's a good question that makes you think a bit. I do not under any circumstances recommend removal unless in the process of replacing them due to damage.

 

[maine89]

Hi Main 89

Wondering how you solved your "talking" bulkheads. I'm just starting mine.

Not sure why I stopped getting email notification of replies to this. I just happened across it reviewing the responses for this year's fixes.

I was not able to dig into it, it was a full time job trying to sail as I kept having one problem or another.

I'm going to look into this some more next time I can get to the boat. I need to examine my chainplates anyways.

 

[RubyJean]

Still doing the refit on my 27. Was looking at my bulkheads, same problem here. Going to replace mine when I can get to it. Mine are very loose and a little disstressed. Thanks for bringing this to my attention, now I have one more thing to do. Better here than 2000 nm from my home port. Hope to leave Oregon coast by July 4, 2013. Heading south, Maybe Mexico or will truck to the East Coast. Someplace warmer where the rum flows freely,haha.... Michael..