Which boat?

I'm no expert but I would have thought an 18 would be a lot more expensive proposition than a SB3 and you'd have to train with a couple of other people quite regularly.  In fact if you are going out in an 18 you really need a RIB to go with you so that's another logistical nightmare.  An SB3 on the other hand can be sailed at 90% with club level sailors and no training and certainly no need for a RIB for company.

100kg is heavy so you are never going to be competitive in anything except a SB3.  I know some top 49er crews and they are feeling on the heavy side at 160 between them.

I'm nearly 90 and I have to face it sailing is a sport for light people.

Might sound silly but have you considered a Hurricane 5.9, the class seems to carry a bit more varied a weight range than the F18 and Tornado from what I've seen but you'll be "more in the know" than me about that because I don't sail cats (much). The 18 foot skiff is a really expensive boat to campaign, i.e. firstly the insurance for the boat is strictly third party and all replacement of damaged equipment comes out of your pocket. To be competitive on the circuit the boat will have to be a decent Murray design and probably best buying a boat with a lot of spares. Seen a few good ones come up for around £7k but in general, you are looking at about £10k upwards for a good boat. I would also not recommend sailing the boat from scratch with crew's you haven't sailed with because handling and tuning wise you need to be communicating very well together. You can almost get away with inter-changing crew on the 49er but it is noticable the difference between people who consistantly sail together and people mixing crews, reckon on the 18s the difference would be much bigger and since there is an extra crew, whilst showing someone the ropes the problems are intensified. If you want to sail for fun, an older design 18 would be a great laugh but a full blown campaign does demand a lot of investment of time and money and an 18 isn't like most dinghies or cats and demands a lot of preperation on shore to rig let alone tune. A lot of the factors I've mentioned put me off moving into the class. 

Originally posted by jon2005 i would love to do that but havnt got the cash to get one. looks like im still going towards the 18 footer anyone want to crew?

Where abouts are you based?

they are quite expensive to maintain, the 18s. new blocks, ropes etc.

How about a new challenge...SB3?