How big is the top one?
Can you sit on the wider part? I wonder if it's a "3rd hand" sort of device for splicing/whipping.
The slidy bit of metal looks like it would trap cord in the 'eye' of the thing, whilst it was pushed through the lay of a rope.
The bottom one is easy - it's a stacking 4mm banana plug
Seriously, I wonder if it's something for smoothing out or setting a splice after you've made it. It would force the rope to bend four times through it, and it doesn't seem to have a cleaning function. The handles aren't strong enough or the right orientation for a Tyrolean traverse runner, and the clips aren't strong enough to take that sort of weight (and there's no obvious attachment point. It looks like it's pulled/pushed along a rope by hand.
I know serving mallets, sailmakers palms, etc., but if these things
are related to rope/rigging work, I've never seen anything like them before, nor in the limited literature I have on the subject.
E.