How many ships in a Scottish Navy?

Reading Hansard's reports of Monday's Opposition Day debate on the Royal Navy, there was some gentle pisstaking whenever one of the SNP members rose to speak. Alex Salmond has apparently promised that the Scottish Navy will be based at Rosyth, but how big will it be?

Well, the Navy has been paid for from the UK's wealth as a whole, so it would seem fair to split it according to the respective shares of national wealth. The ONS gives Scotland a GVA of £82bn as at 2004 compared to a GVA of £1,005 for the UK as a whole. That's about 8%.

Well, we've only got 2 carriers and they'd need 50% of GVA to get one of those.

We've got 25 Destroyers and Frigates, though. 8% of the Gross tonnage of these would give them about 8,900 tonnes worth - that's one Type 23 and one Type 22 Frigate.

We've got 16 minesweepers. 8% of the gross tonnage would give them a Hunt Class.

They haven't got enough points to get a sub, but we could probably chuck in a couple of Patrol Boats instead. So, the Navy of the Republic of Scotland would have a strength of

2 x Frigates
1 x Minesweeper
2 x Patrol Boats

That's all. Carry on.