Excellent topic Fenlander - I've been asking myself the same questions.
My tub is quite a bit smaller than yours but the issues are the same. I keep a bridle permanently fixed to the bow rings - it enters the SIB over the bow tube and I have a loop on it for towing/attaching cargo to/holding on to.
The stern is trickier. Firstly, my transom is very light and I'd be wary of towing anything that was of any weight. I've been wondering about just using the engine itself as a fixing point for a line - any suggestions for where would be best for this?
For either type of tow I keep a bungee handy. I understand that they can be tightly wound round a couple of loops of towing line to act as a kind of damper to lessen any snatch that will occur - good if your fixing points are, um, a bit light.
People find the idea of something this small doing a tow hilarious - but I've already assisted one SIB to RTB. It was Mart C. who gave me the idea, having read his account of towing bigger hard boats. I've seen quite a few craft rescued/towed in locally, and certainly most could be handled by a small SIB (with a big donk
). Think about it - those 6m boats should have a 6-8hp aux. I'll leave you with two words: