Providing the boat has no electrics or gas, its exempt from the BSC, The anual licences are expensive, but you can get day/week/monthly licences (Check their site), A day licence ealier in the year cost me £9.00 for a 17ft Cruiser. They won't issue you with a permit, without proof of insurance.
Insurance for my SIB is £35 per year, from noble marine.
Insure the dinghy with the 5hp, then put the 7.5hp on the back if you need...
Originally Posted by Dirk Diggler
although you may qualify for a discount if under a certain hp rating,
It used to be discounted for 4hp and under, or electric outboard