Its just a guess, Red.

More guesses: The strut is more like a spreader—its in compression.  The forestay comes down to it, the strut holds it to leeward, and the stay continues down to a point on the hull.  That’s just what it looks like to me.  The mast has moved quite a ways to leeward, so the rigging has too.

I REALLY dig that boat.

Thanks Luomanen,
The strut as a spreader does makes a lot more sense.
But at that angle it’s hard to see a mounting point on the forward hull that wouldn’t bring some tension to that strut.
Also without a section drawing i can’t quite make out where the mast is stepped.
It kinda looks like it’s stepped on the windward shear line.
Did the original design have the mast stepped further to windward than that?

Luomanen - 02 December 2013 04:56 PM

It looks like it has struts that move the forestays to leeward, as well as provide windward sheeting points for the main.

It’s possible, but I don’t think it’s likely.  The way the first/last bulkheads are angled inward suggests that they are there to support the forestay chainplates.

red cedar - 04 December 2013 05:05 PM

Also without a section drawing i can’t quite make out where the mast is stepped.

It’s stepped above the companionway hatch.

That makes sense about the bulkheads.

What do you think the leeward struts are for, Greg?

I think that Old Greg is righ for the forestay; if you zoom 400% on the 3D rendering of the Bieker blog site, you will even see that the attachment to that angled bulkhead is off-centered to the lee side, maximizing the angle of the stay with the mast to serve as “caught-aback-mast-down” preventer…

I think the struts are a mini traveler for the main sheet. So you can have some downhaul effect and avoid too much mainsail twist, even if you crack the mainsail loose a bit, by letting the traveler block slide down that short track…

Just a guess, really…

I am also guessing, but I think Laurent has it right…...If you look at the 26 November blog, because the mast is stepped on the highest point on the boat, the boom vang angle is very shallow, especially for a rotating wing mast, which means poor leech control and / or difficult mast rotation, therefore the need for the leeward traveller.

Did you notice also on the same sail plan, the rake on the mast, approx 700mm, which presumably needs to change to the same amount in the other direction, some 1400mm of travel every time you shunt?

Rob Zabukovec - 06 December 2013 07:51 AM

Did you notice also on the same sail plan, the rake on the mast, approx 700mm, which presumably needs to change to the same amount in the other direction, some 1400mm of travel every time you shunt?

Good catch.
How does the rig deal with the variation of length for the forestay and “aftstay” during a shunt?

I like the design (even if I prefer schooner rigs…) but to me, the mast on top of the companion way add a lot of structural challenges/complexity.
In this case, the boat is not big enough to have an “offset” companion way, so the mast can rest on a proper “post” integral to the windward side of the hull, with a companion way on one side or the other. Yes, it makes the cockpit assymetrical; the companion way is on the forward half of the cockpit on one tack and on the aft half on the other tack; so what?

But in this case, since there is not enough room for this, why not the mast even further to windward, on the windward edge of the cockpit, “à la Madness”???
I know in that case, those 2 boats start to look more and more alike, even if it seems to me that this Bieker boat is much more a blue water vessel than Madness.

Another think I am not too fond of…
And then I will stop my rant…

The tiller system.
Actually I like it a lot and think it has a lot of merit; but the fact that it is internal to the boat is a negative point for me. First of all and more importantly, it east up interior space, which is never to much in a slender multihull boat.
Also, for maintenance, if it is encased in that box, there is a good change that one will not keep a good watch on it and you may not be aware of deterioration, or wear until it is too late.

I like much more a completely on deck system like on Jzerro. It might not be as sleek looking as an internal system, but at least, you can look at it everyday, easily maintain it, repair it, change parts if necessary, and it has no impact on internal space.

Don’t get me wrong; overall, I still drool over those drawings…