I may have to concede that Annie’s comments in a previous post should be taken note of. I believe Annie’s analysis was not quite right (ie there can not be a force pressing the [edit]port frame tube against the mast, and the slot in a SJR plays no part in the working of the sail catcher). However, Annie’s analysis was based only on a recollection and with hindsight, I think maybe her conclusion was correct and ought to have been given more consideration. It is possible the sail catcher will not work so well on a contiguous sail, even when set up correctly with the mast in between the two support tubes.
What led me to reconsider was a conversation with Marcus at the recent junket. He too had seen (and I think had been involved with) a sail catcher which did not work at all well, and he repeated Annie’s analysis – maybe it was the same boat, we do not know. Anyway it was a contiguous sail and the sail catcher was fitted entirely on one side of the mast. (If the sail were standard, that would have been the [edit]port side.) Not surprisingly, this arrangement did not work at all. However according to Marcus it was then modified and fitted again in the proper manner with the mast between the two tubular frames – and still the battens would stack up on top and not drop down into the sail catcher.
(It must have been quite a failure. Marcus was in a particularly frank frame of mind at the time he spoke to me, and he told me in no uncertain terms that he thought the sail catcher was a hopeless idea, couldn’t see any benefit and wouldn’t have one himself!)
So, just for the record, I have given some thought as to how it could be that the sail catcher works so brilliantly well on my boat (and Edward’s) – and may not work well with a conventional sail – and here is my theory:
There is no great force pressing the [edit]port tubular frame against the mast. There can not be. The ONLY force on that tube is the tension in the lifts, and the angle between the lifts and the mast is very small. This means the horizontal component of it (that sideways "pressing" force) has to be almost negligible. In fact on my boat there only needs to be a little bit of sail cloth in the catcher and it literally falls open. Even with nothing between the support tubes to hold them apart, the sail catcher is always open to receive panels and battens.
HOWEVER, the tube on the [edit]starboard side does press a little against the mast, and once there is weight in the sail catcher the mast is squeezed a little between the bundle and the [edit] starboard tubular frame. This has no effect on the way it works with SJR, not because of the slot, but because the sail batten parrels are of the running type and not very thick. Either they still manage to slip down between the mast and the support tube on the [edit]starboard side, or they simply unreeve sufficiently to allow the sail panel and its batten to drop down into the sail catcher anyway. (I only thought this through properly on the way home from the Tall Ships junket and have not yet been able to have a look at the [edit]starboard side and see what exactly is going on.) Not having experience with conventional standing parrels, the problem was not intuitive to me, but I am now thinking maybe with conventional standing parrels (possibly thicker and maybe with anti-chafe or padding deployed) the hang up is on the [edit]starboard side of the mast and maybe those standing parrels hang up there and prevent the battens, on the other side of the mast, from easily entering the sail catcher. Perhaps someone else can confirm this.
I stand by my statement that the sail catcher is the best accessory I have ever had on a sail boat, and still recommend the sail catcher to Rudolf and others – for SJR. In fact SJR really does need something better than lazy jacks IMHO.
Thanks to Annie for raising doubts with regard to contiguous sails, and Marcus for independently doing the same thing. We do need to take on board the comments of experienced people.