Where is it best to place the spinnaker sheet turning blocks on a Mk12. Believe originally they were at the stern but as designs became wider were moved to the widest point. How are people rigging them now?

On our 9D they are towards the rear and the helm often ends up sitting on them :-(

CM, I'm glad you have asked this question as I too have a vintage Merlin (908) which I am restoring and was unsure of the location. Look forward to some more replies or images.

Have a look at pics of newer merlins on this site. Normally the block goes through the deck just behind the thwart, though on some older boats I have seen it inline with the thwart. If it is behind the thwart there is often a wooden knee that will need a hole cutting through it in order to thread the sheet through. It then goes through a block and cleat located on the thwart. If you don't cut a hole through the knee the rope probably won't run at the right angle and you would have to locate the thwart fittings to far inboard. This can be uncomfortable for crews to sit on!!!

See how runs through thwart on this modern merlin

Are there any images though of the arrangement on really, really old boats (late 50's early 60's). I have see similar arrangements to that seen on the Fireball where the block, rather than running through the deck as shown in the image, is located as far back as the transom? Thanks

Through Sheaves in deck by rear lifting handles to turning blocks under side deack and cleats.
http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/vintage&file=hamble_1966.jpg

Through Sheaves in deck by rear lifting handles to turning blocks under side deack and cleats.
http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/vintage&file=hamble_1966.jpg

See picture in link of Diabolo 214. Sheaves are by the rear carrying handles, back edge of cockpit as AG says.

At the risk of taking this discussion off at a tangent (I know you all love it really) can I express my confusion that many symmetrical classes I can think of (Fireball, 505, 470) seem to want the spinnaker sheet leads to be right on the transom....yet the Merlins have moved them as far forward as the thwart....why is that?

Plus, in the 50s our kites were tiny, so why were the leads so far aft then? I would expect the blocks to start off mid-way in that era, and move aft as the kites grew...?

as I understand it the place to have them is either as far back as possible and/or with the widest slot possible.

Now I'm getting confused! My Proctor 9b has no spinnaker kit and I was about to cut the deck around where the modern boats have their sheet leads. It does seem strange that the modern boats all have this set-up whereas most symetrical classes opt for as far back as possible. Before I cut hole in the beautiful deck I would like some advice!

Dave

It's all about maintaining as wide a slot as possible between the main and the spinnaker leach. Hence you can either place as far back as possible to minimise leach tension, or - on a wide boat - place at the widest point to pull the spinnaker away from the main.

DaveC, I was of the same dilema, but having read the posts and seen the set up on Diablo I will fix blocks either side of the transom with sheets fed back to block/cleats on thwart. There are no holes in my deck for the spinni sheets to pass so I can only assume the arrangement is as above.

Might be worth setting the boat up and just having a look at whether the boom will ride over the top of the sheet on a dead run as I think you will find that Merlin spinnys fly high and sheeting from the transom doesn't help the angle of the sheet.  My narrowish old Merlins both had the sheeting point a bit aft of the thwart and so do the Mk IX's at Hampton

That's a good point Andrew.

To start with why not put the guy/sheet through the rear lifting handles to see what it's like then make a cutting decision later?

Again, another good suggestion.

Up until about the early 60's spinnakers were set inside the forestay.
So they were only used on the run, 5ft pole and very small spinnaker - the crew held the sheet and the helmsman often held the guy. No sheaves or fairleads! 
Then there was a stage when the sheets had a tennis ball on the end and the crew used to throw the sheet round the forestay and pick it up from the water on the leeward side! This meant it was possible to use the spinnaker on a broad reach. After that it started being threaded through the aft handles.
That was the cutting edge of development, but the start of the 'loads of string in the boat era'

Pat is right, except that he neglects to say the change came about in 1960-1 when we went from a 4'6" pole to a five footer and thence to spinnaker reaching also Seahorse and Leech were cutting flatter spinnakers rather than the old "parachutes", to allow reaching more effectively.

I put mine by the thwart in my mk ix. Not noticed any problems reaching. It would be a right nuisance any further back

Phil is right performance aside, a right pain in the neck sheeting the spinnaker right aft was, a flapping sheet could get round the end of the boom even with stern main sheeting it was a relief to move the sheeting points further foreward and discover it was better too!