A Photo & Discussion Forum for Wharram Design Enthusiasts
Any thoughts on the following much appreciated:
How should the bottom on the jib reefing drum be attached to the bridle? I have a gap of about 7".
Is it a good idea to have an adjuster?
Simplest way to rig the cunningham for ease of reefing
What kind of mast rake should I be aiming for - will it help the tacking..
Anyone got a better way of rigging the mast stays which seem to take ages to tension!
Pictures of my bridle set up are attached. I have just changed to dyneema from u-bolts on the hull but they are not there for tensioning. There are two turnbuckles on the bridle for that. I have just changed all the wires so have had to re-set everything which is best done when the boat is ashore to set the mast rake with the shrouds and do the final tightening on the bridle. It is also easier to walk around the boat and get the angles right. The turnbuckles and the lower eye on each shroud are Sta-lok and are re-used from the previous setup. Once the rig is set and the mast needs to come down I ease the the turnbuckles (after marking them and binding the shroud lashings so they come off neatly) and remove the forestay pin. It seems to work well but there may be easier ways to do it. I cannot think of many alternatives to turnbuckles in order to achieve the required tension and still make slight adjustments. Once the rig is set then it is easily raised again to the same position. Finally this is one of the few times in my life that I have needed to refer to Pythagoras since school!
My mast rake is 4 degrees (from the plans?) but I know others have less. One owner of a Tiki 8m asked if it created weather helm but it seems fine to me. His is nearer the vertical.
My cunningham is simply a hook on the front edge of the mast with a purchase and jammer to attach to the sail at each reefing level on the wingsail. I thought that was the only way to do it and must admit that it is never adjusted that much. The most significant change is a tensioned main track with a 2 part purchase on each side of the traveller. The ability to set the main properly across the width of the boat makes a big difference when running off the wind.
Hope this helps.
I've been digging through my old notes and it looks like the rake of my mast is around 2 degrees, which seems to work fine.
As for tensioning the rigging, I don't have any turnbuckles (bottle screws) anywhere. The bridle and forestay lengths are fixed, once it's in place all tensioning is done on the shrouds which are secured with lashings. I get it as tight as I conveniently can just by tensioning the lashings. After that I loosely tie a mooring line around (say) the aft port shroud, push the loop up as far as I can reach, and tension back to a stern mooring cleat. This causes the forward port shroud to go slack, so I can tighten that lashing some more. I then release the mooring line and take up the resulting slack in the port aft shroud lashing. I then repeat the process, this time using the line from the aft starboard shroud to a stern mooring cleat. You can then do the same thing but putting the line round the forward shrouds instead of the aft ones. If you do this a couple of times you can get the rigging as tight as you want. It's very easy, but you have to keep sighting up to make sure the mast doesn't end up leaning to one side, and also check by feel that you have even tension between the forward and aft shrouds. It sounds complicated but it's actually very quick to do. Another way to check the mast isn't leaning to one side is to measure using the main halliard that it's the same distance from the masthead to the end of the crossbeam each side.
Thank you everyone much appreciated - especially the photos and using the main halyard to check even distance.
I think more mast rake must help tacking (a bit like when you tack a windsurfer) but obviously not to create excess weather helm.