How you leave your vessel at the end of the day may determine whether you return to find it still tied to the dock or 10 feet under. That kind of disaster might happen because of owner neglect or a rogue operator’s carelessness, but it can also happen from an ordinary bout of precipitation.
Boats sink when their interiors fill up with water faster than scuppers can drain it, often because of blockage of some sort. Trapped water flowing into the cockpit or bilge with no easy exit creates tremendous weight. It settles the boat on her lines and then pushes lower and lower until the sea rushes in through scuppers, again adding more weight.
How much weight? Let’s use as a model a 20-foot open runabout with a draft of 24 inches and a beam of six feet. Even allowing for a diminished cubic capacity as the boat narrows toward the bow, that’s roughly 170 cubic feet. Water weighs approximately 62 pounds a cubic foot, so that comes out to a staggering dead weight of 10,540 pounds inside our ill-fated vessel. No wonder why her next destination is Davy Jones’ locker!
If you’re skeptical about experiencing that much rain and water weight, don’t reflect on days gone past, as climate change has knocked conventional thinking on its head. The country is experiencing more frequent and heavier storms — even a single day downpour is heavier these days. According to ClimateCentral.org, the great majority of the country experienced above-average rainfall in 2019, and this chart from the United States Environmental Protection Agency shows the increased frequency of heavy precipitation events in the U.S.:
As the rain falls, your vessel should be draining the water through scuppers and/or into the bilge, where a trusty pump is expected to eliminate it. But pumps fail, scuppers may get blocked, and hoses may wear out or come loose. Thus, these are things to check before winterizing your boat, again in the spring, and periodically throughout boating season. BoatUS says the majority of sinkings are dockside or on moorings, when it’s likely the skipper is not around to bail and call for help.
Be especially vigilant if the scuppers exit right on the waterline instead of a couple of inches above. The American Boat and Yacht Council sets size and minimum heights above load waterline for the placement of scuppers, but some boat builders may skirt the standards.
Also check for other sources of water egress. Hatches need regular examination to ensure they are watertight. Gaskets may be worn or in some cases there may not be any.
Some deck scuppers don’t empty overboard but into the bilge. Those pumps are designed to handle small leaks and nuisance water, not a torrent. The little motor works its heart out, but eventually the battery that runs it discharges and the ship abandons itself.
For the open runabout crowd, it might be prudent to cover your boat with a snap lining.
The author is the Division 5 – Staff Officer Public Affairs, First District Southern Region, for the U.S. Coast Guard Auxiliary, the all-volunteer, non-military arm of the Coast Guard, teaching boating safety education and conducting search and rescue operations. Visit http://cgaux.org/ to join the Auxiliary or for class information.
Checklist to Avoid Spring Sinking
Wet winters followed by rainy springs bring the kind of water boats don’t need. Those boats stored in water may succumb to the overflow, so step in periodically, even if you don’t plan to launch for weeks.
When inspecting your boat, look for these signs of potential vulnerability and repair and replace as required:
- Cracked or weak hoses for the head, AC, muffler, and exhaust
- Corroded or cracked thru-hull fittings and corroded or cracked bolts
- Debris in the scuppers
- Drips, cracks, blisters, rips, and holes
- Dried-out caulking around hatches and ports
- Misaligned coolant lines
- Seacocks frozen open or shut
- Drain plug missing or ill fitting
- Corrosion or shifted strainer
- Shift or loss of stuffing box packing
- Shafts out of alignment
Before departing, rearrange or add extra bumpers to fend off further damage during spring storms.
