Barge Retrofit

Many older houseboats were built with either Styrofoam or fibreglassed plywood pontoons for floatation. Over the years this material has deteriorated to the point of imminent failure, and in some cases people have added weight in the form of additional rooms and decks, putting extra load on the floatation. To place these existing structures on a concrete barge entails building temporary support walls and guides in the barge, and attaching scaffolding to the barge.

Waiting to float onto a barge at Sausalito dry dock circa 1985

The barge is then towed to the adjoining slipway and at low tide filled with water by means of 4” diameter siphons. When the tide rises it covers the barge. At high tide the houseboat is floated into position above the barge and “locked” into position with the guides, lines and winches. As the tide recedes, the houseboat settles into place on the temporary support walls. When the tide has dropped enough to expose the top edge of the barge, pumps are started to remove all of the water from the barge.

Barge just launched and ready to receive transfer of existing home.

On the next cycle of rising tide, the houseboat on the new barge can be floated to the Aquamaison slipway and removal of the old floatation and re-supporting of the structure commenced. This is a labor-intensive process. As a small portion of the old floatation is removed, that portion of the structure is supported. Slowly all of the old floatation is removed and the old structure fully supported. At that point, sealing and waterproofing between the house and the new barge must be carefully done.

Sometimes re-siding of the house is needed as leaks that previously passed behind bad siding and window trim into the bay will now fall into the new barge.

Most older boats have formed a “hog” which is a curving of the floatation, and when placed on a new barge will straighten out, sometimes causing sheetrock to crack, doors and windows to jam.

Aquamaison has successfully completed over 50 of these “float on” retrofits, creating much needed additional living and storage space, and the peace of mind for the owners who no longer have to worry about sinking.