ABYC Seacock Strength Requirements
The ABYC standards are very clear on the testing requirements for installed seacocks yet numerous builders over the years, including many current production boats, blatantly ignore these requirements. The builder of this boat completely ignored the bare minimum ABYC safety standards adn this boat was built by a builder who was an ABYC member/builder.
The ABYC/UL strength test is performed at the innermost part of an installed seacock, usually the male hose adapter, innermost portion of an elbow or the innermost portion of the assembled seacock. The test requires the seacock assembly withstand a 500 pound static load for at least 30 seconds and not allow any ingress of water.
27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water (see Figure 1).”
The European ISO/RCD standards are slightly different than ABYC requiring 337 pounds of force at a position of 20 mm inboard from the internal end of the fitted seacock. This 337 pounds of force is cycled 10 times. The seacock is then tested to 1 Bar of pressure and can not allow any water to leak in and must operate as intended.
Regardless for which standard you choose, a fore arm merely bracing against the hose, while opening a seacock handle, is a gross failure to adhere to either standards and to construct a safe vessel. This should have been installed correctly by the builder but it also should have been noted by the owners insurance surveyor, neither of which occurred. This boat was built during a time period all these ABYC requirements were in place so there was no excuse for this level of cheap-skateism..
Just for grins I tried to press my forearm against my load cell, in order to see how much pressure I could deliver. Suffice it to say I was not even in the ball park, let alone the league, and my arm hurt for a solid week.
There are only a few seacock materials that should really be used below the waterline and those are:
Marine Bronze – In the US this is usually manufactured from an 85-5-5-5 metallurgy. An 85-three-five bronze alloy is roughly; 85% Copper, 5% tin, 5% lead and 5% Zinc. Reputable manufacturers of 85-5-5-5 bronze seacocks and adapters include; Apollo/Conbraco, Groco, Buck Algonquin, Perko & Spartan Bronze. Any Bronze seacock, thru-hull, elbow, male adapter etc. should wear the marine UL labeling and be 100% galvanically compatible with what it is mated to. Mixing dissimilar metals below the waterline is a recipe for disaster.
Forespar® “93” series Marelon – Marelon is a glass reinforced nylon product by Forespar. *Only the OEM / “93” Series Seacocks have been tested to ABYC strength requirements.
TruDesign Plastics – TruDesign is another glass reinforced nylon product that meets the ABYC strength requirements in most sizes.
Please, please, please take your seacocks and below waterline fittings seriously:
- Inspect them regularly
- Cycle them regularly
- Locate them for easy access
- Use marine rated hose intended for below water-line applications
- Use flanged seacocks
- Use non-perforated 316SS hose clamps from either ABA or AWAB
- Make sure your male adapter is long enough to accept two hose clamps
- Do use galvanically compatible materials
- Do use Marelon, 85-5-5-5 Marine bronze or TruDesign Seacocks
- Do not use PVC
- Do not use yellow brass fittings
- Always ensure threads are compatible
For more information on seacocks see the other MarineHowTo.com articles below:
Seacocks Strainers & Hose Clamps
Good luck & happy boating!