I am thinking of buying a newish merlin to do sea opens, some winter thames racing (tamesis or hampton), nationals and/or salcombe each year. Practically new to the class having only crewed one week before. Will be sailing fairly light at 20-22 stone. I weigh 11 stone. I like to keep things fairly standard in a class I am new to so thought single string winder boat with chipstow mast. Other option seems to be an Easy Roller - I note 2 are for sale but they are a little older than I was planning on. Are there any issues re: combined crew weight that effect the preference between these? How many Winder ones are likely to have been tweaked for fat or thin people? Any other variations I should consider?

3635 Aloha won the Tamesis winter series last year winning in a range of conditions. Being on the lighter side of 'light' you might suit an easy roller better, but being a fatty what do I know!?
Anyway Tammy is the place to race this winter, if you want some details give me a shout!

And at what sail number do they start having single string set ups?

They started to appear as an option at 3611 (Dave's own boat on which the system was developed) and became more or less standard after approx 3630 with few boats being built by Winders without it.

The only EZRoller i know of with the one string is Zero Gravity unless more have been converted.

There's a good fleet at Tammy though the sailing conditions there make it very hard to understand why (waits for the flak).  Hampton does at least give a good beat and run with either an easterly or a south-westerly wind and the tea is better after sailing.

A few Winder boats have been tweaked, largely to flatten the rocker and drop the bow, which is what the modifications of the later boats have been.  This will improve straight-line speed at the cost of tacking ability, but in essence all of the modern wide boats (CT, EZ Roller, Let it Ride) are slow to tack compared with the older boats from the 1960's and 70's that do so well on the river.  I suspect the flatter hull will give you maybe a 10-length advantage on a race at the Nationals.  At the top that may be winning or being 5th, but at my end mark roundings will lose/gain you more.

Mark ignore what Andrew says about Tammy all river clubs have their favoured wind direction.. Tammy is great especially in the winter as I don't think any club can beat the number of boats we get out for our winter series generally averaging 14-15 boats from old narrow boats to Winder Mk4's. I think the most we had was 19 boats one winter series race!. We don't have the nightmare of having to get over onto an island such as hampton have plenty of boat parking space plus a boat shed to store boats or work on them. We also have a club steward who provides the best lunches all year round.. Whatever you choose I'm sure you will find both Hampton and Tammy very welcoming.. Though Tammy is better (but then I'm biased!!)

Hang on - he said there was a good fleet at Tammy, should we ignore that too....?

Rob, I've always been unlucky when I have come to your opens, as the wind has been from the wrong direction each time!  That said, I did have my best ever Silver Tiller race there a couple of years ago but the short 1st beat makes for mayhem at the top mark.  The Tammy travellers are doing really well this year - think we have to pull out our fingers at Hampton.

There is now a bit of land on the Middsx bank at Hampton for boat storage & we do have space for new members boats FWIW

its only friendly banter between two river clubs who are situated fairly close to each other and both have large active merlin fleets.. 
And we would love to see some Hampton boats come along for our winter series and we will try to ensure the wind blows from the correct direction to give a decent beat to Teddington lock!

I am sure I will get to do some yachting at both clubs - but only in the winter club racing - chosen mode of transport in the summer on the river will be my rater at Thames SC. Merlin will then be wrapped up for the open circuit. I am presuming a one or two will come on the market after the nationals - which gives me enough time to get a crew lined up. Think on discussion in a few bars I will be keeping an eye out for a single string winder. Not too fussed about river performance  - want to use it to nail the boat handling side of things early on and to do some winter sailing within walking distance of home. Rob - I note yours is no longer on the market. Is that a permanent thing?

Mark- Mine is off the market, was talked into keeping her at Salcombe.. just means not moving house for another year!! Hope to see you at Tammy then for the winter series. Good luck finding a boat, I suspect a few will come onto the market after the Nationals..