Hi all,
Fresh marine engineer here,
Can anyone please share some info about the working principle of OD.Box? How it works from the inside and how hydraulic oil gets pushed into the twin-tubes while they rotate!!
Ive seen a couple of vidoes on YT but they only show how the rocking arms move back and forth.
Thanks
welcome aboard … for me, I"ve sailed lotsa ships but i’m not making the connection here about a od box … i need my memory kicked !!
It’s the reservoir for the operating oil for the cpp. As for my ship, the cpp oil gets sent to the hub from the o.d box via mechanical & electrical pumps. The pressure is kept on the lower shaft & hub via the head or gravity tank. When the engine/gearbox/cpp is running the oil is constantly pumped to the hub that overflows to the head/gravity tank & the head/gravity tank overflows back to the o.d tank. When the engines are secured, sometimes the level in the head/gravity tank will fluctuate with changes in aft draft. When this happens we just turn on the electrical pump that pumps from the o.d box to top off the head/gravity tank. Recently in drydock we had to pull a blade for inspection. Afterwards we refilled the hub with oil but it took nearly 24 hrs to bleed all the air out after the initial refill. Each time the head/gravity tank alarmed we knew an air bubble escaped & we kept using the electrical pump to pump from the o.d box until the level stayed constant.
same here … i don’t know why going thru the rigamarole is so popular.