Propellers, Shafts & Rudders ~ New Jersey Scuba Diving

Propellers, Shafts & Rudders

A huge modern brass propeller ( from the *SS United States* ) on display.

shipwreck Delaware propeller — Looking down the prop shaft at the iron propeller on the *Delaware*. The narrow squarish blades indicate that this is a rather primitive 1880's model, unlike the more modern rounded prop on the *Macedonia* below.

shipwreck Macedonia propeller — The propeller on the *Macedonia*.

shipwreck Macedonia shaft mount — Propeller shaft bearing and mount on the *Macedonia*.

reef Venturo propeller — The propeller on the *GA Venturo* - a completely modern design. Note the wide, round blades.

Breaking a propeller shaft at sea can be a disaster. The propeller stops turning and becomes a drag, while the vessel's momentum carries it forward. The propeller slams backward, extracting the broken shaft and often mangling the rudder. This leaves a large hole open in the bottom of the vessel, directly into the bilges and machinery spaces. On a large vessel with a deep draft and a large shaft, the water comes in like a fire hose - uncontrollable.

The engine is soon disabled, and along with that the pumps, which in any case are probably not big enough to keep up with this magnitude of flooding. The outcome may take several hours, but it is inevitable unless maybe the Coast Guard can fly out a special de-watering pump on one of their big helos. Unlike a collision, storm, or rogue wave, there is usually plenty of time for an orderly abandon-ship, and there are seldom casualties if rescue is available.

Shipwreck Emerald — The "Emerald" fell victim to a broken prop shaft in 1873, and the *Lady Gertrude* sank the same way in 2016.

shipwreck Oregon steering quadrant — The fallen steering quadrant on the *Oregon*, perhaps 20 ft across.

New Jersey Scuba Diving

Propellers, Shafts & Rudders

Shipwrecks

Decompression Theory

An Explanation of Professor A.A. Buhlmann's ZH-L16 Algorithm