As I understand, It uses a stainless spring that rotates with the shaft via bearings. The seal doesn't move on the shaft. There's no rubber mounts.

Two hose barb,,, It's a double engine thing. It's the standard t after the raw water pump and gives positive pressure to water at the seal. The second barb goes to #2 engine. If you don't have a second engine there's a plug to put in instead of the barb. I guess the loop is to supply water to the second engine in case of raw water failure to either.

Hey!! I'm still trying to catch up on a new subject with decisions to make.

Funny,,, We have the boat for sale and I'm still trying to figure out what's best for the boat. This boat needs a dry bilge and no maintenance on the seal. It's the most difficult part of the boat to get to. The worst part of the boats design. I got to do the right thing.