Essential checks for chainplates

As long as our chainplates aren't leaking, few of us give them a second thought. But should we be checking more closely? Surveyor Ben Sutcliffe-Davies explains what to look out for

- Ben Sutcliffe-Davies

There are many methods of anchoring the loads from a yacht's standing rigging to her hull. But how often do any of us think to check them? Traditional wooden boatbuilding techniques persisted in many glassfibre yachts from the 1960s to the mid-1990s, which have the chainplates brought down through the deck and secured directly to a bulkhead. However, since the 1960s just about every boatbuilder has moved away from iron to stainless steel. Many yachts now use a flat bar of stainless with some form of plate welded on to create a deck seal, and sometimes a suitable cant (bend) above the deck to create the correct angle for the wire standing rigging, which reduces rig fatigue by lessening the 'working' of the wire.

Due to changes in rigs and production methods (and the desire to make the internal space of a yacht more open-plan), yacht designers have gradually moved away from relying on a bar bolted to a main bulkhead as the means to anchor it. Many builders have for years used a D-bolt, while others had nice A-bolts manufactured. In all cases there ought to be some form of hanger or rod that picks up the loading and anchors it to an internal stringer, strut, frame or form of bulkhead.

Boxing not clever

On several ranges of yachts, the designers have brought the chainplates through the deck, down into the saloon, and then boxed them in so they can't be seen.

While it may look good, it's a bad idea from an assessment point of view. I've attended a few rig failures on unsinkable yachts, where, on accessing the internal moulding, the chainplate roots were found bonded into the hull using a small, perforated stainless steel plate with a threaded bar welded to it. Water ingress, through a leaking deck seal, had soaked the plate which caused it to fail spectacularly from crevice corrosion.