The saildrive (if it is original) is a 110 model with a one piece collar anode. Standard Volvo fitment. Allen key to undo locking bolt, then undo cone. Prop should slide off but may need a bit of persuasion if it has not been off for some time. Anode also held on by socket screws. When re-assembling use loctite on the prop locking bolt or better still use a new bolt.