ATTENTION PONTOON BOAT OWNERS

The photographs below show the corroded keels on a pontoon boat (one on each hull). Fortunately the owners identified the problem before the hull became pitted and are able to have them rebuilt.

It is understood that the problem arises because the keels are a folded strip in the profile of a "vee", tack welded to each hull. Because the weld is not continuous, water may penetrate to the inside of the strip and work away at it. There is no explanation why equal corrosion does not occur on the unprotected strip of the hull. It could be that the metal gauge is thinner and there may even be, heaven forbid, a mismatch in the metallurgy of the two surfaces.

The keel is necessary as a rubbing strip to protect the circular hull from occasional damage and denting.

The repairer advised that the keels should be replaced with solid plate. This is being done by the owners and will result in no cavities and an ability to anti-foul all surfaces.

Owners of pontoon boats may want to inspect their boats carefully when they are cleaned for anti-fouling. The observation is that corrosion is quite rapid once penetration takes place.