Oday 22 structural question

[calone]

Hello sailors,
Does anyone know if the plywood wall (green rectangle) in the picture is a structural wall?
I know the post (red rectangle) is right below mast bracket, and I won't alter that!
I'd like to replace the plywood wall with a thinner Lexan / Polycarbonate custom cut sheet.
Boat is an O'Day 22

 

[jackhart]

Remember that your chain plate for the port side attaches to that wall. So it is definitely a structural part of the boat!

 

[jssailem]

The simple answer is yes, that wall is structural.

I am guessing that you want to "open up the cabin" by being able to see through to the bow.

The challenge is that the boats are built with a flexible shell of fiberglass and resin. The internal walls, deck, and frames are designed to keep the shell in place and maintain its shape. Making major changes to the interior weakens the exterior. Hey, it is your boat, and you can experiment with modifications. That is often the way innovations happen. It would be good to understand how boats are built and why the design is the way it is constructed before making major changes.

That bulkhead is in the area of the mast. As @jackhart shared, the chainplate is outside the bulkhead. The bulkhead pushes the hull outwards as the chainplate tries to pull the hull inward towards the compression post (the red rectangle). The compression post keeps the hull from collapsing vertically, while the bulkhead keeps it from collapsing horizontally.

Oh, and welcome to the SBO forums.

 

[calone]

I this case I will take the plywood walls out, sand them with incremental grid, stain it and put them back
Thank you everyone!

 

[Timm R Oday25]

The bulkhead is a very thinly layered veneer.It will take almost nothingto sand through the teak . We did both sides so the veneer was the same .
When you remove the port side , use it a a template for the new . Where the through holes are for the chainplate , make sure to soak the soak the holes and top of the plywood with an epoxy . Water will want to enter your boat through holes in your deck .
You really don't want the bulkheads to get wet and rot beneath the chainplates

 

[calone]

I am going to see the boat this Saturday. Living in Ontario, Canada, I will have to wait for the snow to melt to take it out with the current owner. I'm a handyman with lots of knowledge and tools, but not for boats, unfortunately. Looking at those two plywood dividers, I was dreaming to replace them with pure white (sanded) Lexar / polycarbonate, cut to fit. However, the 1/4' Lexar, that I was planning to get, is more flexible, and probably won't help holding the top of the cabin. I may end up taking the panels out, sand them and put them back in, after painting the hole interior. At the same thickness, Lexar is heavier than marine grade plywood.
I am welcoming any suggestions to replace those dividers with something lighter, that would last.
Cheers from above the border!

 

[dlochner]

I am going to see the boat this Saturday. Living in Ontario, Canada, I will have to wait for the snow to melt to take it out with the current owner. I'm a handyman with lots of knowledge and tools, but not for boats, unfortunately. Looking at those two plywood dividers, I was dreaming to replace them with pure white (sanded) Lexar / polycarbonate, cut to fit. However, the 1/4' Lexar, that I was planning to get, is more flexible, and probably won't help holding the top of the cabin. I may end up taking the panels out, sand them and put them back in, after painting the hole interior. At the same thickness, Lexar is heavier than marine grade plywood.
I am welcoming any suggestions to replace those dividers with something lighter, that would last.
Cheers from above the border!

Leave the bulkhead panels in place if they are in good shape. Removing them may make a small mostly cosmetic issue a major boat project.

As already mentioned the plywood has a very thin, perhaps 1/32" veneer with the expensive wood. Easy to sand through. Choose the varnish carefully. Traditional marine varnishes often have an amber tint, it can end up looking pretty ugly on some modern interiors. I've been using TotalBoat Halcyon Clear gloss and semi-gloss on interior wood work and like the effect. A few coats of gloss first and then a coat or two of semi-gloss. Too many coats of semi-gloss often leaves a muddy finish.

 

[calone]

Thank you dlochner!

 

[Project_Mayhem]

The chainplates will need to be rebedded. The O'Day's are a bit notorious for leaks as the factory used silicone to seal everything. BedIT butyl tape is strongly suggested. There's an article about it on HowToMarine.com

 

[dlochner]

There's an article about it on HowToMarine.com

Correction HowToMarine.com is Nigel Calder's site. MarineHowTo.com is Rod Collins' site. Rod and Nigel know each other.

 

[colemj]

If you want to lighten those bulkheads, then paint them or glue a white laminate on them.

If they can be easily removed, I don't see how they could be structural. Structural bulkheads are generally fixed in place in some way like tabbing, glue, molded components, etc. But then, I also can't see how they would not be structural. Small boats can get away with more than large boats in things like this.

Mark

 

[dlochner]

If you want to lighten those bulkheads, then paint them or glue a white laminate on them.

If they can be easily removed, I don't see how they could be structural. Structural bulkheads are generally fixed in place in some way like tabbing, glue, molded components, etc. But then, I also can't see how they would not be structural. Small boats can get away with more than large boats in things like this.

Mark

The bulkhead may stiffen the compression post. While most of the vertical load is carried by the post, the bulkhead keeps the post from bowing or bending in much the same way as the web in an I-beam or an angle iron stiffens those items.

 

[Project_Mayhem]

If you want to lighten those bulkheads, then paint them or glue a white laminate on them.

If they can be easily removed, I don't see how they could be structural. Structural bulkheads are generally fixed in place in some way like tabbing, glue, molded components, etc. But then, I also can't see how they would not be structural. Small boats can get away with more than large boats in things like this.

Mark

Some of the later O'Days skipped the tabbing to the hull. The bulkhead is held into a slot in the liners by a handful of #12 screws. There haven't been any reported problems with this method

 

[colemj]

Some of the later O'Days skipped the tabbing to the hull. The bulkhead is held into a slot in the liners by a handful of #12 screws. There haven't been any reported problems with this method

That's what I meant by a molded component. No problem with that on your boat. Is it also connected to the post? If so, is it also easy to remove from that?

The bulkhead may stiffen the compression post. While most of the vertical load is carried by the post, the bulkhead keeps the post from bowing or bending in much the same way as the web in an I-beam or an angle iron stiffens those items.

It would need to be connected well to the post for that to work in any direction different from directly toward the bulkhead. There would be degrees of freedom in all directions except one. The description of it being easy to remove had me picturing it could just pull out and be put back in with ease like a divider or something.

I don't know anything about the Oday 22 construction - just the description sounded strange for that area.

Mark