Re: Mast Support Beam corroded - Hard or easy to fix?

I have no first-hand knowledge about the Cal 39 construction, but if it is the Lapworth design (as opposed to the later Hunt design) I'd be very surprised if there is not a metal transverse support beam under the fiberglass floor pan. This page makes it pretty clear that it's a Lapworth model -- http://www.cal39.info/cal39mk2/Cal39IINewBoatCBN1976.jpg -- so I'm guessing it's more than likely that this boat has the beam. If you're putting in a bid on a boat, I'd be tempted to ask for a reduction equal to the cost of having a marine yard make the repairs. You could save a lot of money by doing it yourself, but that would be at the cost of your time. Shouldn't the seller pay something for your time? Having said all that, we replaced the beam on our Cal 29 with little prior experience We cut away the floor pan forward of the beam; others made the cut aft of the beam. As my late stepfather loved to say, "You pays your money and you takes your choice." We were replacing all the bulkheads at the same time, so removing the pan forward made the job easier. We used the beam drawings created by the late Roger Jones. Somebody on the list may have a copy of the original Lapworth drawings for your boat, and you may be able to get the dimensions of the beam from those. If the beam is like the one on the Cal 29 (and I would expect it to be) it will be a beam with a vertical web with a flat plate to one side across the top, and a curved plate across the bottom to match the curve of the hull. Roger modified the original design by putting a flat spot in the middle of the bottom curve to provide better drainage of any water reaching the hull forward of the beam. (In my opinion, most of the damage to the original beams is the result of water backing up forward of the beam, leaving it soaked and underwater for extended periods.) When we had our replacement beam fabricated (using a piece of stainless from the fabricator's scrap box), we had them form the top plate by bending the web. This meant that the only welding required was for the bottom plate and the tabs used to attach to the bulkhead. It's a pretty straightforward job, and we accomplished it with the mast in place. (The boat was on the hard on stands, and we used halyards to the deck to stabilize it while the uppers and forward lowers were disconnected.) There's little side load on the naked mast so the risk was minimal and we completed the work without incident. Of course, your mileage may vary. Let me know if you have any questions. All the best, Alfred Alfred Poor 1973 Tartan 34C #288 "Jambalaya" (Former owner of 1969 Cal 29 #132 "Pentaquod")