"The SOA published version of the rules is a little nicer than the 4 page pdf although there's not too much difference between the actual rules from what I can tell."
Cheek ! – they are a LOT nicer AND they include a full set of counters (in full colour no less) to allow you to play the game without the expense of models to begin with.
The essentials of the earlier versions are still the same in v2. but the SoA version includes some clarifications and extra vessel types as well as suggestions for fleet lists and a brief historical introduction. At the price (£3) they are so cheap it is worth a look and worth a great deal more.
I don't know whether Richard Lee, the author, is a member of TMP or not – if he is I'm sure he will spot this and answer the above query. I did the layout and design for the SoA version and worked with Richard on the revisions from earlier versions so I'll have a go at answering but Richard may have a different answer.
My take on the above is that a ramming ship can only sink if it scores exactly equal to the rammed ship (see the last entry in the effect table on page 8). The wording in the rules is quite clear – for a difference of 3 or more it says 'rammed ship sinks' – no mention of the rammer.
In close combat (for which the ships have to be grappled – CC can't occur without grappling, even after a collision) winner takes all, no matter who's move it is. In your example the 3 would take the 4 if it won the CC by 3 or more.
The grappling question came up in a query on another board and (I think) Richard answered that ungrappling was not possible as it added a complication that was, in his opinion, not needed.
If you disagree then I'd suggest that you use a house rule but make it quite difficult and only possible immediately after having a greater score in CC than your opponent. I know Richard doesn't feel his rules should be 'set in stone' so won't mind me suggesting this.
Hope that this helps
Tony Hughes