Water + Sunlight + Nutrients = Scum

That's a formula boaters know well, having seen that green scum line often enough along the waterline. And it's not normally a problem that a little scrubbing won't overcome. But if a boat is left for long enough, and if water manages to pool somewhere in the summer heat, you might just find yourself with a cockpit full of water if your boat's on the hard. What started as a little bit of water in this boat generated enough algae to clog all the scuppers, and water that was over six inches deep when the owner found it. So if your boat is left on its own in the summer heat, on a trailer or on the hard, make sure to stop by and take a quick look every couple of weeks to be sure you haven't started an algae farm in your cockpit.

Insuring Peer-to-Peer

Peer-to-peer businesses have sprung up all over the Internet and allow people with something they aren't using to get money for letting someone without that something use theirs for a little while. Airbnb, for instance, helps you find an apartment in New York City rather than paying for a hotel room, often for a fraction of the hotel price. Peer-to-peer has come to boating, and several companies including Boatbound, Cruzin, and Boatsetter are bringing together those who want to use boats with those who own them. This is a great new way to get people out on the water when they don't have a boat of their own or want to boat away from home. But this rental business model raises some serious insurance issues. Who insures your boat if someone else rents it? Who insures you if you rent someone else's boat?

Photo of Boatbound picture with logo

Most recreational marine insurance policies will not provide coverage during any rental period — no matter whether you are renting someone else's boat or renting your boat to someone else. Some companies may not provide coverage at all if the boat is offered in a peer-to-peer program. While BoatUS Marine Insurance may provide a policy to those offering their boats in a peer-to-peer program, there is no coverage of any type during the rental period. If you would like to rent someone else's boat and you have a BoatUS policy, you can obtain an endorsement that will extend the liability coverage of your boat policy to you while renting another boat. But bear in mind that this supplemental coverage does not provide for any damages that you may cause to the rental boat itself.

The boat peer-to-peer businesses that BoatUS is aware of provide their own insurance policy that covers damages that may occur while the boat is engaged in a rental arrangement. But before you enter into any agreement, check with the peer-to-peer business about their coverage to make sure you are adequately protected no matter which side of the transaction you are on. Boat owners should look at how much the policy will actually pay if the boat is lost completely, how much the payment will be reduced by depreciation if the boat is damaged, and whether salvage charges will be deducted from the payment for damages to the boat. Renters should also look at the liability coverage in the event they injure someone in an accident and make sure it is at least as high as what they have through their own boat or auto policies.

Fuel Tanks Under Pressure

Photo of a gasoline jerry jug

A member from Florida called Seaworthy last summer to complain about his portable gas tank swelling up from the hot sun and causing gas to spew out of his dinghy's outboard motor. Some of his dockmates, he said, were having similar problems, including engine flooding. All of them had recently bought new EPA-compliant portable gas tanks.

The new tanks and jerry jugs have special fittings that greatly reduce evaporative emissions from gasoline. These new-style tanks are required across the country now and boaters will be seeing more of them for sale as the old-style ones are sold out. The problem with the tanks centers around the fact that in order to reduce vapors, their vents don't open until the internal pressure reaches five pounds per square inch. Traditional tanks simply vent to the atmosphere and don't build up pressure. The Florida member reported that his tank swelled up like a balloon in the hot tropical sun. Before the tank reached 5 psi, the internal pressure forced gas into the outboard where it spewed inside the cowling, eventually dribbling out.

Fortunately, there are a couple of solutions to this problem. The easiest is to simply disconnect the gas tank from the engine when not in use (open the fill cap to relieve pressure before disconnecting or connecting; otherwise the hose may spew gas) and keep the tank out of the sun. The other solution is to purchase a fuel demand valve, which allows gas to flow only when the engine calls for it. These are available from gas tank manufacturers and large retailers for about $25. 

— Published: July 2014


Seaworthy, the damage-avoidance newsletter, is brought to you by the BoatUS Marine Insurance Program. For an insurance quote, please call 1-800-283-2883 or apply online at


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