No, I don't think so. It's designed for capturing your line when it's out of reach when you've advanced it. Mine is on 20 ft. of 1/8 in. thowline, which is rated to maybe 250 lbs? The grapple hook can't be too much stronger than that. You could probably straighten out one of the hooks with a real strong pull, but I've never reefed on it much.
My intended purpose is to connect to a communications cable with the grapnel and use it to aid my advance upwards on a broken limb that is hanging on the cable where there is no tie in available directly over the cable.
Life support will be from the main spar.
Should prove to be a real asset on my job.
I decided I better go look at my grapple closer since you have a specific use in mind. The rod stock is about 6mm in diameter. It is quite stiff...it would hold up to more than I indicated in my earlier post. I wouldn't expect to be able to do much more than aid in balance with that setup, but it could work if your angle from main tie-in isn't too severe. I'd want larger diameter line on the grapple for handling. The eye is large enough to take even 11mm line, but the weight would not be enough to cast it well with more than about 6mm on it. I don't reckon you expect to haul on it too much if you are gonna be hooking that cable with it.
It might be a little light duty for my intended purpose.
What I really need is something a little heavier with folding hooks that will pull up along side the main stem and stay secured in place with an elastic band or strap.
It will be easier to take up into a tree and the hooks will fold up when dropping it down through the limbs.
I'll see what I can fabricate.
I think I found the design I'm looking for in this anchor...