Subject: Re: [harryproa] Re: asymmetric spinnaker
From: Rob Denney
Date: 12/9/2012, 7:41 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 


re. the cost of downwind extras: i would think adding a spinnaker to a unarig would be a vastly cheaper way of adding downwind sail area then adding a second mast or even lengthening a single one. aerodynamically better too. and lighter. and used with a sock or a furler i don't see the douse as being more of a hassle.


All true, but the spinnaker is only used occasionally, the extra mainsail area all the time, except in big air, when the spi would not be used either.  The spi will also need a sheet winch and possibly a tack winch depending on how it is set up.    The mast will also be heavier as it has to be designed to take the load from bear the top rather than evenly spread.  None of which are deal killers.  Get hold of an old spinnaker, tie blocks near the top of the mast and on the beam andhave a play.


re. wyliecats:
http://www.sailinganarchy.com/fringe/2002/catty.htm
"They are untouchable upwind especially in a breeze... WylieCat's are not down wind rockets"

", but they are always sailing at maximum speed." 

which implies it is a hull shape thing as much as lack of a chute

http://forum.woodenboat.com/archive/index.php/t-154551.html 

"they haven't done well in the big downwind ocean races. 

Bandicoot (30) finished 9th out of 24 boats, most of them larger, in the solo Transpac this year.   pretty sure they were winners of the solo and double handed Farallones races (beat out, run back) for many years.

"The <wyliecat> 48 can beat a Santa Cruz 50 upwind in 25 knots...

Maybe 

downwind in light air you'd feel the lack of a chute."  

i believe at least two wyliecat 30 owners have added poles and symmetric spins to their rigs, and at least one was dismasted because of the holes drilled in the mast to secure the pole's collar. http://groups.yahoo.com/group/Wyliecats/message/452


Broke at the holes, which had not been reinforced.  Pretty basic mistake.  Any idea how much faster the 2 spinnaker boats were compared to the rest of the fleet?  Only two after 20 years of competitive mixed fleet racing, implies that the speed gain is not huge.    


it is also interesting to note that the wyliecat 44, which came out after the 30, has a spinnaker listed as a factory option. http://www.wyliecat.com/models/wylie_44.html


Spinnakers for a boat like this are for people who like tweaking and pushing hard, but this is not what average cruisers want, if they can get downwind performance without it.  

For racing performance, you have to offset the extra weight (spi, sheets, winch, mast beefing up, halyard) that you are carrying around all the time, versus the speed it gets you in certain conditions.  On a heavy boat, it is a no brainer, add the spinnaker.  On a 700 kg Solitarry, 35 kgs is 5%, which is a lot.  

FWIW, I am discussing this very subject with 2 very experienced racers who want harrys.  Both want the extra sail area, whereas I think it is not worth the weight.  If either project goes ahead, we will be investigating it in depth to come up with an answer.  I will let you know.


since we're on the topic of wyliecats, could you please help me understand the tradeoffs between a wishbone boom, as they have and as you've drawn for solitarry, and a boom with a rigid gooseneck as exists on all your other boats. the former is only under compression, the latter is bending as well. the former's weight is more aloft, but is it lighter? better control of sail shape with one or the other? more windage with the former when lying ahull i guess.


Wishbones are great for tube masts, except that they put a lot of strain on the batten ends, sail slides and sailtrack if the sheet is eased enough to make the mast rotate.  Not a problem with Wylie cats racing,  but something to think about for an offshore boat.  
They are very complex on wing masts.  Team Phillips is the only one I know of, and that was very messy.   
Wishbones are harder to build, lighter (higher cog) and less complex to trim, than fixed booms.  They are also draggier.  Not sure how much of each factor is a big deal, suspect very little.


i ask because i wonder about the possibility of using a wyliecat rig, not just the design but the actual real thing, on a harryproa. the wyliecat 30 has a sail area of 590 sq ft and the wyliecat 39 has 910 sq ft. your 12m harry is listed as 452 sq ft and the visionarrys are listed as 774 sq ft. close enough


but does a free standing mast need to bend differently on a multihull than it does on a monohull? does the greater initial stability of a proa warrant a more flexible mast so it handles gusts better? if the two could be identical, then it might be better to have them manufactured here, by the same manufacturer, using the same mandrel, than making them two-piece shippable:

http://www.composite-eng.com/composite-engineering-spars/spar-photos-videos-and-links

Harrys have much higher righting moment than monos, so I suspect the mast would be too flexible.  However, Ted van Dusen, who builds them, could easily add more laminate, and/or use a bigger mandrel to solve this.  He is a nice guy, drop him a line and ask for a price, then let us know. 
Composite Engineering - Van Dusen Racing Boats
277 Baker Avenue, Concord MA 01742
978 371-3132   978 369-3162 (fax)
www.vandusenracingboats.com 



rob
--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
> All that aside, downwind extras are a good idea if you want to go faster
> and don't mind the added hassle and cost. Tacking the headsail to the beam
> is the same aerodynamically as the ballestron jib when the rig is eased, so
> no problem. Go for it.
>
> I am a keen follower of the Wylie cats, although it is very hard to get any
> credible information on them. Where did you get the "they are pigs
> downwind" information from, please?
>


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