Bi-Pod mast
Sorry going to have to be very brief answer this morning;
Steve Clark said:
This may be one of those ideas that hasn't worked in the past because of material limitations. I think the masts have ended up being very heavy and loaded with spreaders and wires because there is so much compression in the rig. Driven by the need to set a tight forestay on a very long foretriangle. I think this has resulted in rigs that have more weight aloft and rigging drag per square foot of sail area than more conventional sloop or cat configurations.
In past experiments this does appear so...excessive heavy rigging, etc. But I don't think you would describe
Procyon's rig in those terms. The legs of the mast replaced the spreaders and shrouds of the traditional rig. This rig actually turned out lighter in weight to the traditional rig.
I don't understand your reference to a 'very long foretriangle' . Neither Procyon nor my mast-aft rig carries a longer forestay. Note that my masthead is located approx where the traditional sloop rig would place it. I will have more to say on another related issue concerning the superority of some aft-raked mast rigs (and with long forestays) (and from actual full size sailing experiences)
Problems that won't go away are the inefficiencies of boomless sails when reaching or running and the balance problems( lee helm) that occurr when shortening sail.
Where do you derive this conclusion that boomless sails are more inefficient? In fact, very often the boom misforms the ideal shape of the mainsail....in addition to other misgivings. Granted a boomless sails (mainsail) may be more of a challenge to get really sheeted ideally, but the payoffs can be significant. Otherwise just get it close as most 'cruisers' do and be happy about not having to dodge that big heavy swinging boom.
Balance problems?? I assume you are referring to my mast aft design? This is a ketch variation, not a sloop or cutter. I venture to guess this rig will not only balance better, but have a greater range of balance positions, and not be one that will drive your bows down with such force when off the wind.
Bipod masts never appealed to me. Once you got the luff wire of the main tight enough, the compression on the spars made them heavy. And you still have more windage than you want.
Bipod mast didn't necessarily appeal to me either, but Procyon's one is rather elegant. Roller furling mains do require a little more luff tension than std ones. But this load is actually trying to 'spread' both legs of the bi-pod apart. So our 'inner spreaders' (cross spreaders) are only going to have to resist a pulling apart of the two legs (tension load). These inner spreaders can now be made of the newer hi-tech synthetics, and thus smaller in cross section and drag.
Another view of the subject might be that these bi-pod mast sections are pre-disposed to bend in one direction, so restraining them is easier than trying to keep a straight single mast tube in column that wants to bend in either direction when under a compressive load.
So now do we really end up with more rigging drag??
Couple of other points:
Yes because the rigging is more aft than conventional it will induce a weathering effect. But look at where the 'heavy weather' sail is rigged.....on the inner forestay.....balance.
Procyon's extra rigging drag was more forward inducing a lee helm...not a feature one wishes in very heavy air
And at anchor this rig will have less tendency to sail around its mooring as it has its drag center aft of its hull center.
Wing and wing downwind is easily accomplished.
I did not like the fact that Procyon's headsail had to be self tacking and thus non-overlapping. I felt this feature lost much of the extra efficency potential of the headsail.
AO Smith's paper on......sorry have to go
