Survey Stuff....Composite Bronze Frames and Floors in Wood Sailing Vessels

Last week I had the pleasure to survey a Swedish built wood sloop (tight seam mahogany on bent oak - copper fastened)...what I would like to share is that this vessel was fitted with bronze composite frames and floors - which is rarely seen today....here is comment from my survey report.....

The vessel is fitted with composite bronze frames (especially amidships - in transmitting the compression strain of the rigging through the chain-plates to the keel) via cast bronze floors. According to Herreshoff, in heavily ballasted sail vessels (greater than 33 percent of displacement), metal floors help stabilize the floor to frame connection at the keel in respect to the all important garboard seam and therefore should be employed. Without proper reinforcement at the floor – frame joint, there is a tendency for the rigging to pull the frames slightly upward thus causing the garboard seam to opening up and leak. Upon inspection, slightly aft of the mast step, a sawn wood floor timber surrounding a keel bolt was observed to be slightly distorted (mushroomed) from unknown cause, but never-the-less, galvanic current or keel bolt strain (as described herein) should not be ruled out and therefore monitored on a regular basis. It is the opinion of the undersigned that the sided dimension of the affected floor timber is properly twice the size of the keel bolt.

FYI: This sloop has a 5,400 pound cast lead keel ballast with Monel keel bolts...