In England the "gate" was similar to a temporary needle dam: a set of boards, called "paddles", supported against the current by upright timbers called "rymers" which normally kept the level of water above it to navigable levels. Boats moving downstream would wait above the lock until the paddles were removed, which would allow a "flash" of water to pass through, carrying the boats with it. Upstream boats would be winched or towed through the lock with the paddles removed. Considerable skill was involved both in removing the paddles in a timely manner and navigating the boat through the lock. Flash locks of this type have been documented since at least 1295 C.E.