Re: proper carabiner?
Nearly every carabiner I've ever seen is aluminum. Whether cast or billet, aluminum is soft and is easily bent. Bend it fast and it breaks. And then there's the hinges on the things, the hinge point is just a weak link in an already weak link.
I'm surprised mountain climbers trust the things, I wouldn't.
ok I can help you with this, I'm a trained/certified high angle tower rescue climber, yeah you are right most carabiners are aluminum but for life safety they are not, steel 2 stage autolocking 53kn (or stronger)is the only type we are allowed to use for top anchors and safety lines/apparatus, any situation carrying the loads, aluminum carabiners are for positioning only, any safety line has to use the steel 53kn(or stronger) carabiners.
Mountain climbers, things are different, weight is a big deal so carrying steel is not an option, often times they go with multiple anchors on the same point in order to make a safe anchor point, or they may set multiple anchors along a pitch in order to provide a safer situation knowing that the possibility the line may pop multiple anchors and zipper is real, hopefully one holds LOL
And that's why I question the reasoning why you shouldn't use spring hooks to attach anchors to bow eyes, I have extensive experience in the use of carabiners, caming out is a very real situation for me, were always aware of it because well we can die if they fail, long fall with a quick abrupt stop. But this situation is completely different, I suppose it could be possible to cam out but I have a hard time seeing it, you need slack and twisting to cam out, over time with swirling winds yeah I can see anchor line twisting to the point where it begins to bind the spring hook and then cam out but I'm not sure my boat will be on the water that long!