The best preventive maintenance for seacocks.........If your boat must be left in the water, the thru-hulls should be protected by closing all seacocks and gate valves. Leaving a thru-hull unprotected over the winter is like going on an extended holiday and leaving your home’s front door open! Failure to close thru-hulls is a major cause of loss in the UK. In a recent study of claims, seacocks or gate valves left open caused or contributed to the sinking. It should be noted that raising and refurbishing a boat that sinks, even at a dock, is a daunting job that can keep the boat in the repair yard for many weeks over the spring and summer. Whenever a boat is stored in the water over the winter, all thru-hulls, with the exception of the ones for cockpit drains, must be closed or it could be on the bottom next spring. And all thru-hulls, especially the ones for the cockpit drains, must be double-clamped with stainless steel hose clamps at each end. This is critical. When water freezes it expands and will lift a poorly secured hose off of a fitting. The hose itself is also important. Lightweight hose and PVC tubing can rupture or crack. Use only a heavily reinforced hose, especially at cockpit drains.
Skin fittings below the waterline and most within about 30cm.above the waterline should have seacocks fitted. No plastic or nylon fittings should be fitted below the waterline. (these can fracture )
 |
| One way to stop those drips……..whats underneath ? |
 |
| If a seacock is completely frozen, it's best to haul the boat before attempting repair or replacement. If that's not possible, then temporarily plug or seal the penetration from outside the hull before attempting repair. Out of sight out of mind and easily overlooked or neglected seacocks and through-hull fittings can cause very serious problems when not maintained. |
If your boat has thru-hulls below the waterline that can’t be closed, either because they are mechanically frozen open or have broken (typical with gate valves, which is why they are not recommended), it should be stored ashore for the winter.
Seacocks are closed by moving the handle down so that the handle is parallel to the hull. Gate valves are closed by turning the wheel clockwise. After the seacock or gate valve has been closed, remove the hose so that it drains and then use an absorbent cloth to eliminate any residual water, which can freeze and crack the nipple. (Taking off the hose also assures you that the valve has closed properly.) Reinstall the hose immediately and secure the two clamps.
It should be noted that thru-hulls above the waterline are not required to have seacocks and most don’t. That doesn’t mean that these thru-hulls aren’t vulnerable. Ordinary plastic thru-hulls deteriorate in sunlight and have been broken when they were shoved underwater by the weight of snow and ice in the cockpit, which then sinks the boat. Plastic thru-hulls near the waterline are especially vulnerable and should be replaced with bronze.
The best preventive maintenance for seacocks, both plastic and metal, is to periodically open and close each valve. Leaving a valve in one position for an extended period of time can allow it to freeze up. Manufacturers' guidelines may differ slightly, but the consensus is that the handle of each seacock should be moved throughout the full open/close path every few weeks, or at least once every 30 days, more frequently if possible. One school of thought advocates closing all seacocks each time the boat is left unattended. If you follow this diligent strategy, be just as methodical coming back aboard, especially to make sure valves on the raw-water intakes are open before starting the engines. If you are forgetful consider putting a placard somewhere near the ignition switch as a reminder.
If a seacock won't operate freely, disassemble and lubricate it. To lubricate seacocks while a boat is in the water, use the following procedure:When the boat is hauled out, perform steps four to six from outside the hull to lubricate the opposite side of the valve mechanism. Use winch, wheel bearing, or water pump grease. Avoid lithium or other metal-based greases, which may cause galvanic corrosion.
close the valve.
remove the hose or tubing from the inboard side.
remove any remaining water from inside of valve.
swab waterproof grease on the inside of valve mechanism.
reattach the hose or tubing, checking clamps or fittings.
activate the valve several times to spread the grease.
steventruss1@aol.com 
