Bulkhead question: Cat27

[jaydducote]

The previous owner of the my c27 reduced the bulkheads to open up the cabin. The walls that enclose the head are no longer there, but sections of the bulkhead remain that hold shelves above the head. The interior is really nice, but I'm concerned about the structural integrity without the walls extending all the way to the center post. Is this going to reduce the ability to bear loads on the deck above, or should the center post and fiberglass be sufficient? What about when sailing and heeling over... will the lack of the bulkhead walls that enclose the head give me any problems there? Are there any proposed solutions to this?

Thanks!

[mitiempo]

Pictures would help with an answer if you can post one or two.

[jaydducote]

Yeah, I thought about that after I made the post. I'll get back to the boat and take some tomorrow.

[jaydducote]

You can get some pictures of the boat at SEA GULL 27 but I dont think any of them really show the bulkheads that well.

[jaydducote]

This is the best picture I could find for now. The shelves on the left side of the picture are built into what is left of the bulkheads. This is on the standard interior format of a Cat27. The head is in a compartment underneath the desk with a laptop sitting on it.

[ulferlingsson]

The thing to consider is the rig. The mast brings a downward force in the center. The shrouds bring an upward force by the hull. This tends to bend the hull up, and to compress the deck and bend it down in the center. I suppose your mast is on deck but supported underneath, since that is the most common arrangement.

Judging from the above photo, the risk seems to be that the deck buckles, if it is not strong enough. Perhaps delamination of the core can result. That's what I think happened in my boat, since the port side (right below) is much weaker structurally than the starboard side.



On the other hand, there is a hint that he left some support under the deck. If so, that might be enough.

Suggestion: Measure some distances with the rig loose. Vertical, diagonal, etc. Then tighten the rig to specs (some 20% on the shrouds) and measure again. If the starboard side is much different than the port side, you may have to do something about it.

On the lighter side, you decoration (plants!?!) suggest that you may not be sailing the roaring forties with her exactly

[jaydducote]

Haha... yeah, those aren't my decorations. I've only had her for a couple weeks. The previous owner fixed her up as a liveaboard but I'm trying to get her ready to sail!

[GaryHLucas]

Generally speaking, in fiberglass boats, most bulkheads are not structural, especially with respect to the mast loads. If the boat has compression post under the mast, then the deck doesn't actually carry the load. In fact it is trouble when the compression post doesn't carry the load, and the deck does. This often happens when the compression post is wood and the bottom rots out. Or when the post is aluminum or stainless, but sits on a wood block that rots out.

On your boat, if the chainplates are attached to the bulkheads which were cut away, then the concern would be about how the bulkheads are attached to the hull, not the deck, in most cases. Decks are usually installed after the interior is in, so the builder really doesn't want to glass the bulkhead to the deck at that point.

Hope this helps,

Gary H. Lucas