I like this idea. I enjoyed the depiction of grappling hooks in the Star Trek: Enterprise TV series, and can imagine it in Elite. Perhaps as a utility slot module?
Please no...
Every time anything is suggested people jump to utility slots! Does no one fly any small or medium ships?! Those slots are full!
If you wanna use a cobra for instance, you ideally want to have manifest scanner, wake scanner (yep, ideally, you want this) and then - oh wait, out of slots...
I mean, you don't NEED either, but they are very, very fine piracy tools, the manifest scanner is almost exclusively useful to pirates (almost) and the wake scanner allows you to persue juicy targets. You could swap that out for a heat sink launcher to run a stealthy build perhaps--- anyway, there are very very very few utility slots on most ships. There are a fair few on the huge beast ships yeah.
I feel like it could actually be a limpet (dont kill me!) as long as - they implement the limpet rack they have spoken about, man that needs doing so much! it's crazy how many of those there are, and literally impossible to do much with the megaships unless you have a very very specific loadout for megaship interactions - and let's face it, it's a lot more fun if you can "come across" a megaship/installing, and then decide to do some stuff, rather than park up, re-outfit your entire ship, for one go.
Wow I went off topic a little I think.
Grappling hook/grapple limpet YES
Utility slot NO NO NO NO
Ability to escape said grapple/limpet YES - And it shouldn't really be any harder than it is right now to escape. Reboot/repair, or AFMU etc, and just run.
The hook/limpet should simply enable the ability to bring ships to a stop, that's it, doesn't need any more functionality.
Alternatively - make knocking out thrusters bring ships to a slow halt on it's own (I'm aware it makes no sense, but neither does a bunch of the flight model anyway, gameplay over realism is required in some cases) - and this would I think, be a very simple (but less cool!) solution.