Does anyone run a continuous pump system for the kite? Or is the extra friction to much? What's the advantages of running separate up/down?

 Yes, a number do and yes you need seperates due to the tension in the elastics
 
If correct, friction is not an issue. Tensions and leads are key. 
 
Send me your email and I'll give you access to the dropbox file of photos
 
 

Barnsie, i think the question is anyone used one string continuously for the pump up system same string for up and down?
and not as the drop box with a string for up and a seperate string for down....

 Simon, Dropbox is an online storage system where we store all our video footage and photos which allows us to give individuals access to individual files.
 The take up on the pump generates to much tension. If the downhaul has tension when the kite is up, it will cause issues with the setting of the kite. Hence why 2 seperate lines, but one elastic cascade system

 The issue with using a pump halyard on the existing system is that you need to have take-up tension on the halyard to 'retract' the line between pumps and the downhaul would not provide this, therefore you need to have a separate halyard and downhaul.
 
Barnsie, would you be able to send me the link to the photos as I'm considering retro-fitting this system, my e-mail is stu.a.m.bates at gmail.com.  Thanks

err yep i know what  dropbox is... you sent me the files, i think matt is talking about the halyard string goes all the way round, so as such is a onestring continuous system that only 'pumps' up and is pulled down.
as per your photos on the dropbox file yours is split? the halyard and take up on starboard side and the downhaul and take up on the other (portside)
 

It is as Simon says, one string connected to the kite at either end. Other classes do it and I've tested the idea by attaching blocks to walls and floors and it seems to work fine. There is still bungee in the system to allow for the pump and pump retraction but it's just a simple one with a release system to allow the kite to fly and engaged again for the hoist.

I just wondered if anyone has tried and found it problematical or if it's not been looked at? 

Looking at that the RS700 class uses the continuous system, along with some Fireballs.  Might be a worthwhile option.

 Stuart will email later. We tried one string and found in light airs it pulled the centre of the kite down from the patch, hence our going to duel string. Unless otherwise proven to me, would only consider the route we have now gone down as hassle free and no friction if the mast internals not crossed, but that could be said for a straight hoist as well
 
 4 seconds from getting the handle to fully hoisted. Great and enjoy it especially in big winds as crew does no need to go forward in seas

Barnsie can you add me to the Dropbox? Gbrspratt at gmail.com then I try a scheme what I'm doing!

Thanks Barnsie for that.  This is what I found on the single string version.

 
This may be better, not sure that last post worked correctly.
 
http://www.draycotewater.co.uk/fleets/fireball/html/pump-up___pump-down.html 
 

That's basically it Stuart, but without the pump down bit. The test I tried worked very well.

Stuart, your link should have been emailed to you this morning

Hi, although admittedly not a Merlin, I’m currently redesigning some systems for a new National 18. It’s basically a Merlin put in a photocopier at 140%...
I’m thinking about the pump system for the kite and would love to have a look at your Dropbox for some inspiration!

[email protected]

Manx thanks

The RS 700 uses basically the same as Stuart’s fireball system too. Thought it’s a bit easier to see what’s going on on such an open cockpit

"... for a new National 18. It's basically a Merlin put in a photocopier at 140%."
 
:-)
 
Except that the crew have to go through a cloning machine !