Originally Posted by Barra
So what do you guys do when your boom is flopping around in light air with some adverse wave action given most cats dont have a vang?
I find traingulating the 2 main sheets and the topping lift anchors the boom and stops the main depowering. After a tack i just give the loosened topping lift a little flick and retighten to the new windward side of the main.
Ive got a decent roach but not that much up high (see the avatar) so the "flick" is pretty easy. I can see that getting more tricky the longer the fat head.
What do you guys do in these conditions?
You needn't have a topping lift at all; even lacking a conventional vang. As, assuming that the mast will take the loads, the simple (theoretically) solution is to "invert the vang". So that the section which would normally attach to the mast underneath of the boom, does so, instead, above the boom, on both sides of the mast.
Although, as I said, the mast needs to be strong enough to handle such loads. Since it's not a configuration which commonly designed for, in many vessels, when a Naval Architect first starts to pen a design... Let alone retrofitting a boat for such.
But... sleeving masts (internally), & or adding doublers (externally), may be viable options. That, or adding more laminate, if it's a CF mast.
Both of which are done fairly commonly on racing boats. Though, much less now, than a decade or 3 ago.
Also, if you go with said variety of unconventional vang. You'd likely need to do a bit of "re-wiring", regarding the running rigging
in that neighborhood.
Is KISS. And it's to simply beef up your lazy jacks enough so that the windward one acts as topping lift. Assuming that you have/can make, attachment points for the lazy jacks, which are strong enough to bear such loads.
Likely this is doable, sans too much trouble or expense. Plus, then, you can also dispense with the conventional topping lift entirely, as a 'free' perk.
Do something vang wise, akin to was done on the 12m's. In that you mount a hemispherical (or semi-curved) track to the deck
(cabin house roof). And attach a vertical vang (hydraulic or mechanical), with an integral return force/system, to a car on the cabin
house track, as well as to the boom's underside.
Needs be, even adding a short section of track to the boom's underside, & a car to same. If you require some ability for the vang to be moveable on the boom. So as to compensate for a non hemispherical track on the deck/cabin house roof.
The caveat to this idea being, that you'd need to consult with your boat's designer
, in order to get the nod, regarding the cabin
house taking those kinds of loads. And, or, for his specs delineating how much to beef up the house, where, & how.
While this would be far from cheap
. You could go to a cored carbon fiber laminate, type boom. So that it's weight would be much, much less than a conventional one.
Meaning; you have an inner composite shell (to the boom), laminated to a core
, & then an outer composite shell on top of that. Just as is done in hulls & decks.
They're very light, & very stiff; in addition to also making your wallet "very, very light", as well
PS: There are also many other unconventional vang configurations out there. Most can be found on various classes
of racing dinghies... although they'd need a bit of scaling up of course.
But even Bruce Schwab's Ocean Planet
went though a few different variations of unconventional vangs (& booms). Even with her freestanding mast. So finding a solution's possible.