Daisy chain

Howard Lennox of Lexington Park, Maryland, asks:"I'd like to know how to inspect (for corrosion) a chainplate that is encapsulated inside a bulkhead. Are there any nondestructive tests I can perform to determine a chainplate's condition without having to cut into the bulkhead?"Don Casey replies:When a through-the-deck chainplate begins to
Author:
Updated:
Original:
daisy_chain

Howard Lennox of Lexington Park, Maryland, asks:

"I'd like to know how to inspect (for corrosion) a chainplate that is encapsulated inside a bulkhead. Are there any nondestructive tests I can perform to determine a chainplate's condition without having to cut into the bulkhead?"

Don Casey replies:

When a through-the-deck chainplate begins to show signs of corrosion, it will almost always be where the deck surrounds the chainplate. If there is a leak around an encapsulated chainplate -- a when-not-if scenario -- the leak can submerge the entire chainplate base in stagnant water, and corrosion will begin. That's why encapsulating a chainplate is a very bad idea, and if you're not able to do a visual inspection, it is impossible to be sure that it will not fail in the future. Although you can x-ray a chainplate in place, the process is not cheap and there's a chance the x-ray will miss some potential flaws. Ultrasonic testing is another possibility, but even under the best of conditions the accuracy of the results depends a lot on the skill of the operator.

Unfortunately, the best way to deal with an encapsulated chainplate is to remove the encapsulation, inspect the chainplate, and then, if necessary, mechanically attach the existing and new chainplates in a way that will produce the required strength but also let you monitor the metal's condition in the future by visual inspection.

Related

Prop-Coat-Barnacle-Barrier-Quart-No-Background

Gear: Prop Coat Barnacle Barrier

Prop Coat Barnacle Barrier 1792 is now available in a quart-size can and, as always, can be used on all underwater metals, including saildrives, shafts, strainers and folding and non-folding props. Two or three coats are recommended, after which the coating will purportedly ...read more

DY_171021_6877

Boat Review: Seawind 1600

Seawind Catamarans introduced its 52ft 1600 model in Europe last year, where the boat promptly started winning awards. The more jaded among us may look askance at such things, especially when it comes to a bluewater-rated catamaran billed as a providing a combination of ...read more

01-LEAD-Sailing-upwind.-300-dpi

Cruising: Australia’s Rugged Southern Coast

After a hard 33-day crossing in the Roaring Forties from Cape Town, South Africa, Jeannie, my wife and shipmate of over four decades, and I arrived to kiss the dock in Albany, a small but well-serviced Victorian town on Australia’s southwestern coast. We were glad the trip was ...read more

ETNZ_14_5687-2048x2048

BREAKING: A Kiwi Spy in the America’s Cup?

Emirates Team New Zealand announced this morning that security breaches have resulted in leaked information and defamatory accusations against their 2021 America's Cup campaign. The campaign has suspected a leak for six months, sweeping their base for bugs and testing firewalls ...read more