Bolted Fittings Rust (Evil Ferrous Cancer)

Have had this Astus 20.2 XL trimaran for over a year now. With the exceptions of a couple of days sails on nearby fresh water Lake Tarpon, sailed on local salt water bays and Florida gulf coast. Always wash the boat down at the ramp or at home with power washer after each sail. Spent some time a couple of weeks ago detailing with extra effort on stains cleaning and marine wax cleaner.

Now seeing places where rust was developing under the bolt-on fittings. The manufacturer had used some kind of white sealant to set the fittings in place. Obviously, the sealant was either cracked or somehow becoming permeable by water. The the evil rust cancer develops on the stainless where water is trapped. Don’t know exactly what the original sealant was employed but do not think it was 5200. 5200 for sealing fittings is generally not the best anyway.

So now the process is motion. When I can, disassemble the bolt-on fittings, clean and re-bed with butyl tape. I followed the suggestions from the site MarineHowTo by Rod “RC” Collins. Clean the parts, string-out the tape by rolling in your fingers to a thread and wrap the bolt as shown. Also bed the whole base of the fitting. Seat the part and tighten down firm not sung hard. Wipe the the excess that squeezes out. Next day, tighten again more snug, wipe off any excess and you are done. The description from RC that I found to be very instructional and specific on re-bedding fittings with marine type butyl tape is found this page: Rebedding Deck Hardware Page 2 including specific examples of boat fittings bedded over 29 years.

Also I have increased the washer size on the fittings that are expected to take a load from time to time. Above, the nut-washer picture is a bit soft; anchors the pad eyes on upper sides of the cabin deck where the lines for lateral stabilizing the mast raising are thread, now have larger fender washers (on a bit if irregular surface). The pad eyes above were re-bedded with butyl tape.