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Cofferdam and Wing Passage Aboard Cruiser OLYMPIA

By Patrick McSherry
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An experimental scheme for additional protection at the waterline which was used aboard U.S. war vessels including OLYMPIA was the cellulose cofferdam. The cofferdam was located just above the protective deck, at the water line. It consisted of a sealed compartment along the hull and protruding inward several feet. The interior of the cofferdam was packed with cellulose - basically shredded corn cobs, etc.

The theory on the cellulose was that, if penetrated by a projectile at this location, the cellulose, when brought into contact with the inward flow of water, would expand. The expanding cellulose would squeeze off the water flow, and basically seal the hole. The idea sounded good in theory, but did not work in practice. Even normal leakage caused the cellulose to rot and smell. The material was soon removed.

Wing Passage on the Cruiser Olympia

The wing passage. To the right is the cofferdam. To the left is the bulkhead separating the wing passage from a coal bunker.

The cofferdam can most plainly be seen when traversing the wing passage, which is a long passage that passes between the outer hull and the coal bunkers, etc. just at the waterline.

The wing passage on OLYMPIA is somewhat reminiscent of the wing passage on the USS MAINE. On the MAINE the wing passage became well known, since men moving along this space would have had to pass by and touch the bulkhead enclosing the coal bunker, thought by some to have been on fire. Crewmen who passed through this area on the MAINE noticed no heat coming through the bulkhead, one of the arguments against the coal bunker fire theory of her loss.

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