A Photo & Discussion Forum for Wharram Design Enthusiasts
These are not hard to splice up yourself, but they can also be purchased in different sizes at Colligo Marine.
Mouzzer has the soft wingsail gaff rig as hown on the T38 plans. I'm not sure why Wharram doubled the aft shrouds on the foremast, but I did think about it as I was building the boat. The loading on the forenast shrouds is the greatest, as it takes the load of the jib and foremain together on the wind, and the foremain and spinnaker off the wind. The foremast moves around quite a bit in the mast casing because the shrouds can never really be tightened down because it's hard to get the deadeyes really tight and the boat wracks a little bit as she sails, changing the masthead hull distance. If the wind is over fifteen, our leeward shrouds are hanging fairly loose, but it doesn't seem to be a problem.
I think Wharram doubled the shrouds to spread the load, since its's greatest on this mast, and perhaps as an in place spare. It's hard to get the tension on the shrouds exactly the same, but it probably works out as you sail. The other reason they might have doubled the shrouds is fixity. By having the tension on the mast taken up in two places several feet apart, you basically force that piece of mast to remain straight; that is, any bend in the mast due to rig loading (and the masts do tend off in the middle) must start below the lowest cleat, and the fact that the top of the mast is fixed above that point stiffens the mast for some distance below the lower attachment point and consequently forces any bend down lower. Consequently, the mast is less likely to be forced out of column due to sideways forces from the rig operating in the middle of the mast.
Thanks for the picture, understand about the soft hanks. hadn't considered that before. Good solution, but I would still monitor for chafe.
The cleats on Mouzzer are made per plans of white oak, and attached to the mast with two number 14 sel;f-tapping screws that are at least three inches long. (They may be longer (I don't remember) but I do remember I had to special order them.) The cleats were also epoxied in place, with large filets all around. The force is mostly directed against the mast and down on the the thumb part of the cleat, so the force is taken by the screws (in shear) and the filets (in compression). If you only used the screws, they might eventually start to crush the softwood of the mast and possibly fail at some point in the future, so I think you need both the screws and the epoxy. The upper part of the cleat retains the shroud loop if it goes slack, but never takes any real force. The cleats themselves are perhaps four or so inches long, about 1 1/2 inches wide, and somewhat over an inch in depth, with a cutout on the mast side for the shroud about an inch tall and maybe a 1/2 inch out from the mast (about the size of the shroud).
The aft mast in practice generally hangs from one shroud, and I worry more about losing that shroud when the rig is stressed, mostly from fatigue at the eyesplice making the loop. I know at least one other T38 has lost that shroud there, but saved the mast because they kept a forward halyard led to the two beam as a precaution. The forward shrouds on the mainmast are the most vulnerable to this, as the mainmast moves around quite a bit in the waves, jerking the slice back and forth. I think that some of the builders with soft rigs have gone to making a separate loop to go around th mast, and then connecting that to a loop on the shroud, allowing the splice the freedom to move back and forth, but I don't have any hard data on how it was done or if it worked. The aft shrouds are supported at least in part by the mainsheet and are I think less of a problem. I have one halyard on the forward side of the mainmast, and on long passages I would keep it fastened down to the two beam as a precaution. Some of the other builders who have put soft rigs on the boat should chime in here, as I would like to hear more.