You need at about 3 times as much material (=crosssection) when making stuff out of alu then you would out of stainless steel. That is because its max strength is roughly 3 times less.

We can go into details but I think this will suffice for now.

You can also get stainless steel wires and have them act as a dolphinstriker. As Hans for more info on that as he has used this setup frequently on his own boats.

Wouter