Flood Port Grates

[ricknelson]

Does anyone know if WWII Fleet Boats Flood Ports had grates on them? I asked the Pampanito folks to take some pictures of the bottom of the boat while it was in drydock to find out but they said all of the Flood Ports had been welded over. They did referb the sea water chests for the engines and motors while she was in drydock and they do have grills.

I checked the Drum last sumer but the bottom is not visable.

Thanks for any help.

[boss subfixer]

During WWII the ballast tank

During WWII the ballast tank openings did not have anything over them. Later in their life time the navy did put bars over the openings to keep unwanted guest out.
This according to my wifes uncle who served aboard at least two fleet boats.
Don

[goose814]

Grates were not added to

Grates were not added to flood ports until the USS Nautilus (SSN-571), when it was discovered she would vibrate at high underwater speeds due to her original open flood ports. Grates were then added and the vibration went away.

Gus

[ricknelson]

Thank you. I had read

Thank you. I had read in Concepts in Submarine Design by Roy Burcher and Louis Rydill that flood ports would produce drag and noise could be radiated as well. The forward-looking edge at the aft end of the hole would act similar to how a flute or pipe organ acts. A resonance could be induced which would result in fatigue cracking. To overcome those effects a flat bar grill would be fit across the opening with the bars across the flow direction and angled away from the flow. I just had no idea as to when this preventative measure was first implemented. It makes sense that these affects would not become pronounced until submerged speeds increased over what diesel boats could do.

I wonder if the Albacore had this problem and if grills were added to her. Anyone in the Portsmouth, NH area that could stop by and check her out?

This is something that detailed scale nuke boat builders need to add to their flood ports. Sounds like an item for the photo-etch people to offer.

Thanks again.

[PaulC]

I want to say there

I want to say there was a picture of Albacore showing flood grates in an old issue of the SCR. Back when Dave wrote about the development of Skip's kit.