In general, with any U-Boat type, when the necessity arose of having to rescue someone from the water, or when boarding from lifeboat or raft, did the crew use a temporary rope ladder, or were there ladder rungs welded to the sub's hull to make boarding easier?

I've never seen or read any references of welded on hand holds on a U-boat or submarine. What images I've seen of rescue involving a has had a person on the sub reaching a hand and/or line for the person coming on to the sub:




U-Boat rescuing survivors from a ship it torpedoed:

There are recessed foot/hand holds in the turtleback ( the non pressure superstructure) they look like half circles cut into the sides

One could also use the free flood holes in the casing if there were some in the right place. Welding on handholds sounds like a way to generate noise and drag for very little benefit though. Rescuing people by a vessel with very little space already was not that practical, unlike the way the larger US subs sometimes operated in the Pacific.

Is that for WWII boats, more contemporary ones or both?