Glossary · Keels, foils & rudders
Hydraulic ram
Also called: Vérin, vérin de quille, ram, keel ram
A hydraulic piston that swings a canting keel or adjusts an appendage.
The keel ram takes enormous loads: it holds several tonnes of ballast tilted in rough seas. Its failure is a feared breakdown, as the keel then swings freely. On recent boats, other rams adjust the rake of foils and rudders.