Cataraman berth design feature question

[BlueBuddha]

Hi all, I have a couple of questions about a specific design feature of cat berths.

Some catamarans have some sort of partition right in front of the bed with a hole cut out so that the bed is entered through a window-like hole. What is the name of that partition? See for example this picture of the FP Lipari:



Other cats do not have such partition. Most often I don't see the partition in modern wide hulls (e.g., Helia 44), but even in "thin" hulls sometimes the partition is not there. See for example this pic of the Outremer 51 with no such partition.



So besides the name, what is the purpose of the partition? Is it simply a design style or does it provide a needed structural support for the hulls? If so, how do cats that don't have the partition compensate for the lack of the support provide by the partition?

Thanks! bb.

[jaybird1111]

That is a bulkhead, sometimes known as a 'ring frame,' and yes, it is structural. Just depends on the design. There may be longitudinal stringers making up for the bulkhead, the hull shape makes a big difference, the construction materials... many variables.

In the pic of the Outie, I'd guess that the vertical with the (door panel?) on the left of the foot of the bed, and the horizontal base of the bed, act in similar fashion

[BlueBuddha]

Originally Posted by jaybird1111

That is a bulkhead, sometimes known as a 'ring frame,' and yes, it is structural. Just depends on the design. There may be longitudinal stringers making up for the bulkhead, the hull shape makes a big difference, the construction materials... many variables.

In the pic of the Outie, I'd guess that the vertical with the (door panel?) on the left of the foot of the bed, and the horizontal base of the bed, act in similar fashion

Thanks so much!

[monte]

Yep, what jay said, it's a bulkhead and provides structural support. Usually there will be at least 4, located between the engine and berth, berth door, Fwd cabin door, and fwd cabin bedhead. I'm pretty sure the outreymer has one where the camera is but the fisheye lens makes it look bigger. Bulkheads provide stiffness to the hull, I can't think of any designs, mono or multi that don't use them, but there my be some monocoque type constructions that don't rely on them as much as others.

[monte]

You can see the bulkheads pretty clearly here
http://www.aeroyacht.com/wp-content/...15-620x389.jpg

[monte]

Or here ...

[BlueBuddha]

Originally Posted by monte

Or here ...
Attachment 99687

That makes sense. It looks like the outremer puts the bulkheads forward allowing for no (or minimal) bulkhead in the aft berth?

The Helia 44 does something interesting with theirs. It is only visible on top and slightly on the sides, but it gives the feeling of an open room as supposed to the more traditional bulkhead look.

[barnakiel]

Originally Posted by monte

(...)

but there my be some monocoque type constructions that don't rely on them as much as others.

Exactly. A carbon monocoque hull can be built for cruising, without any bulkheads nor stringers.

b.

[monte]

yep, we have similar to the Helia. It makes for a nice outlook, feeling of space, but only really achievable in an owner version, otherwise theres no privacy.Id say the Outremer has similar in the owners hull, just not visible in that picture. Over 4m without a bulkhead is pushing things, but anything is achievable by design (at a price)