Hi Julian.
Glad to see you are fitting a ladder to the BCs stern - vital safety precaution, let alone a swimming aid. I wouldnt trust a telescopic job myself....no evidence or experience of them, just predudiced against something that possibly MIGHT jamb when most needed.
Have any other double-enders out there solved the re-boarding problem yet?
I have reverted to the old rope ladder (hard treads) tied to the cabin top grab handles. It works better now I have lashed a large fender to the step that is normally about 6 inches below the waterline. the boat still heels alarmingly but the extra bouyancy - and clearance from the hull - is just enough to enable a really determined/scared person to wriggle and grunt their way back on board. This, obviously, takes time to dig out of a locker and set up so is only useful for deliberate swims. No use at all for emergency single-hander overboard stuff.
Thinking of cobbling up something using an inflatable life jacket mechanism and a drogue, arranged to pull overboard from a trailing line. The idea being to give you a step up AND stop the boat sailing on. The Four Sisters CBL will track for miles if I stiffen up the tiller with shock cord - as I tend to when single handed, for ease of rolling cigarettes, making coffee, etc.
Anyone have a better idea? (Apart from giving up Fags and Coffee, of course.)