what exactly are these?
 

http://www.modellversium.de/galerie/...2342-32048.jpg

On alot of WW2 subs (US) and seen on ships of that era? are they just prop guards or something else?
always wondered.

I've always wondered that too tbh. At a guess I'd say they were to protect the props from depth charges, but I'm not sure.

It's simple - they were for the water skiers to tie on to :haha:

I dont know, but I'd guess they might be for keeping the submarines from banging against the dock and damaging the propellers.

They prevented docking lines from getting caught in the props.

Ah right, makes sense.

I found that out from reading about the SS Grunion which was sunk off the Aleutians. Seems prop guards were rare at that stage of the war. Part of the articule states.

"The Grunion had a propeller guard, which was rare in subs of the day, Abele said. The vessel discovered yesterday also had the fence, which prevented docking lines from getting caught in the propeller."

Prop guards. Always thought they were there to keep the props clear of piers and other obstructions in port. Never heard about their use against dock lines, but I guess that makes sense as well.

It was my understanding that they were temporary 'in port' attachments and were removed prior to leaving on patrol. If that is true then it is strange that Grunion would have had them when she was lost.