San Juan 21 Class Association

Hello all

Son kevin has bought his first boat - a 1976 San Juan 21 Mark II of course - and she needs bulkhead and window replacement badly - I am aware of the bulkhead process, but haven't done windows.... is there a write up on this anywhere?

Mike R
Ragtop #1694

Hi MIke, In such a small boat, I question the need for bulkheads. I got rid of mine and replaced them with metal T straps to attach my chainplates to. There is no way that the cheap little bulkheads built into these boats have any strength to them. Regarding windows, I believe from what Don Casey suggests, silicone is the best sealant for this job and the only place he suggests putting silicone on a boat.
All the best
Bill

Mike and Kevin - I would replace the bulkheads in some fashion in a Mk2 or 3 because of the deck design. The raised sheer doesn't have alot of diagonal rigidity - it's essentially a big box and can benefit from some triangulation inside. I would go with a "ring frame" concept for the bulkheads - ie. fitted against the overhead and hull, bolted to the pan at the bottom but radiused out along the inboard edge rather than a vertical edge. This will save a lot of weight, give you more room to move around down below and provide plenty of strength for the rig loads. If you glass the bulkhead to the hull, definitely use epoxy and land the bulkhead on foam against the hull to prevent a hard spot. Regular 1" blue board insulation styrofoam is fine with epoxy...it dissolves in polyester - which should NOT be used for any structural joints. Cut small trapezoidal strips as thick as the plywood on top and twice as wide at the bottom. A couple layers of 4" glass tape over in epoxy and you should be fine. The foam isn't necessary on the cabin top as it's cored. It sounds more complicated than it really is.

Thanks -yes we plan to do 'something' as to a replacement bulkhead - had not intended to glass it to the hull but may consider that...

His cabin top is surprisingly stout - looks like the caulk around all the fittings was well maintained - and now it has a great cover on it.

On another note, the boat has some slight deformation on the V berth where the mast compression post lands. Thinking of using a piece of aluminum to spread that load out a bit....thoughts?

Kevin/Mike R
#1598/#1694

Krysia,

i think i have seen a picture of your bulkhead set up somewhere, but i can't seem to find it. did you have it custom fabricated, or did you do it with off the shelf parts? I agree with your points about strength of the wooden ones and it would give some more space. I even thought about dousing them in that liquid rubber stuff to soften the blow should you bump into them.

thanks,

Kuriti

Hi Kuriti,
The posting is on Fleet 1's site under chain plate repair in the forum. They were just made of steel as I don't sail her in saltwater and I used silicone to seal the washers and bolts. I went down to a local welding shop and had them made in an hour for 60 bucks, cleaned them up and painted them Tremclad gloss black. I used 1/4" bolts to attach the base, replacing the useless little #10s that were original. My bulkhead boards were at least a 1/2" from touching the cabin top anywhere so did not support the deck at all. Had I hit a strong wind before replacing them ( I did it the day after I hauled her home), the chainplates would have ripped right out of the bulkheads. My deck does not flex and I know my chain plates a rock solid.
Good luck
Bill

Thanks Bill!