What are the "fins" near the stern of some warships?

[nerdboy64]

While clicking around in my port, I noticed that many ships in both the USN and IJN tech trees have some fin-shaped scaffolding on either side towards the rear of the ship. They're particularly prominent on the early American destroyers, but they appear in some form on most destroyers and cruisers from both major tech trees. They don't have anything mounted on them, so what purpose did they serve?

[Khovax]

I was told by other alphas who are in to this stuff that it is to prevent people that fall overboard from geting sucked in to the propellers 

[Im_The_Seeker2]

I was told by other alphas who are in to this stuff that it is to prevent people that fall overboard from geting sucked in to the propellers 

 

They aren't underwater, so they wouldn't be terribly effective at that.  They're probably to prevent the props from hitting the pier.

[dmccabe]

or prevent prop damage from being rammed

[Jinxed_Katajainen]

 

They aren't underwater, so they wouldn't be terribly effective at that.  They're probably to prevent the props from hitting the pier.

 

Pretty much to prevent it striking anything the ship comes up next to.

 

Note how far the props stick out to the side in relation to the hull.

 

[donaldEpott]

Ya I was going to say Prop Guards.

[Irishwind]

Prop guards.  When ships are rafted they get really close to each other.  And water being water, the ships bounce around, and the ships moving in and out could end up ripping the bottom out as one is maneuvering in or out of port.

 

 

[nerdboy64]

Thanks guys, that makes a lot of sense now. At first I thought they were for attaching something to the side of the ship, but couldn't think what of what.