Some more detailed stats:
We spend an average of $75 per trip on towing: with a $5 turn up fee we really need a minimum of 15 people per trip (obviously this largely depends on where we go!).
We spend an average of $100 on petrol per trip; with a total of $2986 on petrol approximately $3 per dive goes towards petrol. For maintenance of $4030 (excluding gear servicing) = $4 per dive. So $7 per dive is more or less covering the running, registration and maintenance of our boats and trailers assuming that these number are proportional to the amount of diving (and they should be more or less). These dollar amounts are probably a little low because the total dive numbers for 2006 include a small number of shore dives which obviously do not contribute money towards the boats.
In 2007 we will also need to include a contribution towards marine insurance and registration costs ($3000), based on 2006 diving this should be approximately $3 per dive.
So we should definitely charging $10/$15 rather than $7/$12 if we want to save money towards boat replacement and gear purchase but can still afford occasional perks like the student punch card and $5 diving for N&R).
Given that equipment servicing was not covered by gear hire we need to be careful to make sure that we are covering this expense as well as the cost of replacing gear either in our membership fee or hire fees. We may need to consider how we structure gear hire prices in the future (for example a flat rate of $10 rather than a reduced fee of $5 for one item).