Sea Chest Requirements

[tmartin125]

My company is preparing plans for installation of an additional sea chest on a large vessel. The sea chest in question will be located in a ballast tank with reach rod access to the ballast supply butterfly valve. ABS regulations require means for clearing the strainer plates which is typically done through compressed air connections however with the sea chest being located in a ballast tank there would be no access to compartment and I am at a loss as to how this would be achieved. Anyone have any thoughts?

 

[MikeHalloran]

Put it somewhere else.



Mike Halloran
Pembroke Pines, FL, USA

 

[tmartin125]

Thank you for that insightful response however if that were an option it would have been decided upon long ago.

 

[MikeHalloran]

Move it in the topological sense.

I.e., build a big cylindrical bulkhead around it, with a ladder and lights and enough space to provide access, effectively reducing the ballast tank volume by the volume of the access space. The bulkhead is externally pressurized by the ballast water, so it has to be thick and/or stiffened, and it has to seal against the hull at the bottom and against the tank ceiling at the top, and be watertight, and probably needs to meet whatever specs the hull itself has to meet, and will require analysis to see how it affects the hull strenght and life, and...

by the time you get an honest cost estimate together for something like that, the simpler alternatives already rejected will magically become much more attractive.



Mike Halloran
Pembroke Pines, FL, USA

 

[CH5OH]

i don't see the problem;
on the bottom level of the ballast tank you would have:
-sea chest with shut off valve
-ballast valve
-airline with shut off valve (to clear sea chest)