Older Car 27: any ideas on how to open up the space?

[xavpil]

Hi all
i have a 1980 cat 27
Both bulkheads serve as a separation wall for the head Or the closet across from the head.
I don’t need the head or the closet
I would like to open up the space to make the v berth open,, visible and useful. More like in the newer boats.
Chain plates are attached to the bulkheads so I would definitely leave some material there

Has anyone done this Type of conversion?

 

[Davidasailor26]

I don’t know about the Catalina 27, but in general builders use bulkheads for more than just the chainplates - they’re also a key component to the structure of the deck and hull. Unless you’re sure that they weren’t used for that in your model I would be reluctant to reduce their size.

 

[xavpil]

This is a good point.
However the bulkheads are 8mm plywood
Any engineer around ?

 

[David in Sandusky]

I'm an engineer. Davidasailor26 has a very valid point. Mid ship bulkheads often support hull shape.

But that is not an engineering opinion - the engineer you need to answer your question would understand the design of your Catalina 27 bulkheads. And I am ignorant of the specifics, sorry!

 

[JBP-PA]

I have seen boats where people replaced bulkheads with a steel beam to provide the support.

 

[xavpil]

I'm an engineer. Davidasailor26 has a very valid point. Mid ship bulkheads often support hull shape.

But that is not an engineering opinion - the engineer you need to answer your question would understand the design of your Catalina 27 bulkheads. And I am ignorant of the specifics, sorry!

Thx for the input
I would also think they serve a structural purpose but the way they are built tells me - far from being an engineer - that fiberglass or stronger material would have been used.
They seem to serve the purpose of offering privacy and storage. But again I have no idea

 

[xavpil]

I have seen boats where people replaced bulkheads with a steel beam to provide the support.

I like the idea. Also considering I will be doing light coastal cruising
Thx!

 

[Calif. Ted]

Chain plates are attached to the bulkheads so I would definitely leave some material there

In your "after" photo of a Cat270 the stainless rod to the left is part of the shroud/chainplate system, I don't think it is advisable to try to cobble something together for an "open floorplan". I couldn't find a diagram for the 270 but the 320 is a larger version, if you'll notice the diagram at left on first page. The shrouds are attached to solid hull structure, in your boat that is by the bulkheads, remove the bulkheads and you compromise the rig.
https://www.catalinayachts.com/wp-content/uploads/2016/12/cat_320.pdf

 

[Hollyberry]

I'd say the forward 'walls' of the closet and head might be non essential (but may also support the forward lower shrouds) The chainplates MIGHT be supportable by substantial knees glassed into the hull/deck areas but I'm pretty certain the major main bulkhead serves as hull shape stabilization as well as chainplate anchor.
Also the wood mast support post would probably need to be replaced by a SS tube like most newish boats.
I think it's risky plan, but a the end of the day it's your boat and in reality not a giant write-off if it doesn't work.

 

[markwbird]

I am also an engineer and you should not remove the bulkhead. It is a structural member by design.

 

[Davidasailor26]

Thx for the input
I would also think they serve a structural purpose but the way they are built tells me - far from being an engineer - that fiberglass or stronger material would have been used.
They seem to serve the purpose of offering privacy and storage. But again I have no idea

Depends on the direction and type of force they’re handling. For example, a lot of bookcases and shelving units have very flimsy back panels. The unit without the back panel will be wobbly and fragile. Once you tack the flimsy back panel on it holds the unit square and it’s much stronger than you’d think from the strength of the parts.

Looking at the pictures more I agree with Hollyberry that the port side panel *might* not be entirely structural. How much of it is structural for the chainplates and side deck versus how much is for the locker partitioning is hard to say.

 

[xavpil]

For example, a lot of bookcases and shelving units have very flimsy back panels. The unit without the back panel will be wobbly and fragile. Once you tack the flimsy back panel on it holds

good analogy

QUOTE="Davidasailor26, post: 1765247, member: 63309"]
… hard to say.
[/QUOTE]
yes that a the whole problem actually

Thx for the input

 

[xavpil]

.
I think it's risky plan,

I am agreeing more and more actually

 

[David in Sandusky]

Another input: 8mm marine plywood with all it edges fastened can easily counter substantial compression from those edges,. The hull in this case. I do know for a fact the the bulkheads in our h27 are designed to support the hull shape.

 

[xavpil]

Another input: 8mm marine plywood with all it edges fastened can easily counter substantial compression from those edges,. The hull in this case. I do know for a fact the the bulkheads in our h27 are designed to support the hull shape.

good point
thx David

 

[xavpil]

I am also an engineer and you should not remove the bulkhead. It is a structural member by design.

Thx

 

[jssailem]

The bulkheads are a part of the boats skeleton. Like your rib cage, they give the boats fiberglass skin shape. They resist the forces of the mast rigging used in sailing by maintaining the shape of the hull.

Remove them, your hull and deck will collapse based on the engineered design of the Catalina 27.

The thickness of the plywood used in a bulkhead is designed to maintain the boat shape and function, yet be light enough not to weigh down the boat. It is not chip board, press board nor is it solid boards. It is stronger, lighter, and more water resistant.

The modern open designed boats have been designed using a different method with the required structure molded into the hull and pan (hull liner)set in to the mold. They have the same design function but in a different structure.

Just like an old car that gets chopped and altered into a jalopy or street rod, it is your boat and you are free to attempt to alter and chop it into what you desire.

 

[xavpil]

The bulkheads are a part of the boats skeleton. Like your rib cage, they give the boats fiberglass skin shape. They resist the forces of the mast rigging used in sailing by maintaining the shape of the hull.

Remove them, your hull and deck will collapse based on the engineered design of the Catalina 27.

The thickness of the plywood used in a bulkhead is designed to maintain the boat shape and function, yet be light enough not to weigh down the boat. It is not chip board, press board nor is it solid boards. It is stronger, lighter, and more water resistant.

The modern open designed boats have been designed using a different method with the required structure molded into the hull and pan (hull liner)set in to the mold. They have the same design function but in a different structure.

Just like an old car that gets chopped and altered into a jalopy or street rod, it is your boat and you are free to attempt to alter and chop it into what you desire.

Thanks for the great input

 

[Calif. Ted]

You don't know it yet but you have bigger fish to fry than interior modification, here's a few things to check more closely, there are others.
Electrical
Engine Wiring Harness Upgrade for Universal Diesel Engines
Standing rigging:
Stainless Steel Crevice Corrosion
Spreader Bracket Retrofit Kits for the Catalina 22, Catalina 25, and Catalina 27
Lashing the Upper Shrouds to the Spreader Tips

 

[xavpil]

You don't know it yet but you have bigger fish to fry than interior modification, here's a few things to check more closely, there are others.
Electrical
Engine Wiring Harness Upgrade for Universal Diesel Engines
Standing rigging:
Stainless Steel Crevice Corrosion
Spreader Bracket Retrofit Kits for the Catalina 22, Catalina 25, and Catalina 27
Lashing the Upper Shrouds to the Spreader Tips

Wow!!
Ok. I’m selling my boat