[Rhodes22-list] Hull Speed
Steve Alm
rhodes22-list@rhodes22.org
Sat, 27 Jul 2002 04:12:58 -0500
Thanks to all who responded to this. I've taken note and will use these
references in the future. I'm not a racer, I'm pretty casual out there and
my boat partners and I are more into just enjoying ourselves. Dick, thanks
for the caution about pitch poling but I really don't expect the R22 to be a
"go fast" boat. I have a laser, a Prindle cat and a wind surfer to use when
I feel the need for speed. I posted the question because I simply want to
get a handle on what the boat's capabilities/limitations are. You've all
provided me with some benchmarks now that I can use to check how the boat
and the skipper are doing as I get better. I try to sail the R22 in a safe
and comfortable way and try not to get too aggressive. I leave the X
sailing for the laser when it doesn't hurt to push the envelope. If I don't
dump the laser once in a while, I'm not trying hard enough ;-) I have pitch
poled the cat! It has no reef points so we were at the mercy of the
elements. On that day, they showed us no mercy! Thankfully, there was no
damage or injury. I also spent a lot of time hooked into the trapeze of
Hobies out in the the Gulf near Naples. (Dick, as I recall, the Hobies were
at the beach at 14th S.)
The R22 is the biggest and driest boat I've owned. As Roger pointed out, my
rig (IMF and 175% Doyle) is the antithesis of what we would call
high-performance. I realize and except that but I think I ought to be able
to get reasonably good performance out of what I have. I'm just trying to
get a focus on what my expectations should be.
Again, thank you,
Slim
On 7/26/02 8:17 AM, "Roger K. Pihlaja" <cen09402@centurytel.net> wrote:
> Steve,
>
> With a 20 foot waterline length, figure hull speed is 5.25 knots on a Rhodes
> 22.
>
> Remember that Dynamic Equilibrium is a 1976 Rhodes 22. It's lighter & has
> the old style high aspect ratio centerboard vs. current Rhodes 22. Also
> remember that we have a very roachy fully battened mainsail, a 150% genoa
> made of Bainbridge Cruise-Lam (tm) composite sailcloth on a Harken unit 0
> roller furler, & we're rigged to fly a tri-radial spinnaker. With the
> current Rhodes 22 configuration & your individual driving habits, your
> mileage may vary.
>
> In flat water, Dynamic Equilibrium can approach hull speed 1st on a broad
> reach with a wind speed of about 8-10 knots while flying the tri-radial
> spinnaker. Close reaching with the tri-radial spinnaker requires about 9-11
> knots of wind to achieve hull speed. Our standard rig achieves hull speed
> on a broad or beam reach at about 11-13 knots of wind & about 12-14 knots of
> wind sailing close hauled.
>
> If you read my story about the weekend cruise on Saginaw Bay with my son,
> Gary; then, you will note that by exploiting waves & surfing, the Rhodes 22
> can significantly exceed its theoretical hull speed. This cut our transit
> time across Saginaw Bay (27 nm) by 20-25%. However, note that this
> intrinsically involves sailing the boat "actively". It's great fun, but
> demands concentration, experience, and close cooperation between the
> helmsman & sail trimmers.
>
> It can be done with the boom in the upper position. We sail with the boom
> in the upper position up to about 15 knots of wind speed. On Dynamic
> Equilibrium, lowering the boom is triggered by having to dump the mainsail
> traveler to leeward more often than about once per minute due to wind
> direction shifts &/or wind gusts. Naturally, this trigger point is a
> function of wind speed/direction, but is also affected by crew weight,
> number of crew, & willingness of the crew to function as "live ballast". In
> passive mode (i.e. if you don't want to sail the boat "actively"), you
> should lower the boom at about 8-10 knots wind speed.
>
> However, sailing with the pop top up &/or the bimini top is just a big drag
> & should be avoided if you care about going fast. If the order of the day
> is comfort, elegance, & entertaining friends out on the water in light air;
> then, by all means sail with the pop top & bimini top up. We do it all the
> time. The speed penalty is greatest sailing close hauled. With a wind
> speed of about 10 knots, sailing close hauled with the pop top up will cost
> you about 1 knot of speed & increase the angle of heel by 5-10 degrees.
> Under the same conditions & close hauled point of sail, the bimini top costs
> about 2 knots & increases the angle of heel by 15-20 degrees. As you can
> see, sail close hauled with both the pop top & bimini top up & you can end
> up going pretty slow, heeled way over, with a huge weather helm. Therefore,
> try not to sail close hauled with the pop top &/or bimini top up. The
> speed/heeling penalty from the pop top &/or bimini top is not so bad on a
> beam or broad reach & almost negligible on a run.
>
> I've only sailed on IMF equipped Rhodes 22's in light air. So, I can't
> comment on what conditions would be required for one of the new boats to
> surf. I would think a big tri-radial spinnaker would be the sure cure for
> any inefficiency in the standard rig. But tri-radial spinnakers can be
> tricky to sail, especially for a novice - the very antithesis of the way you
> have your boat set up.
>
> Steve, I hope this discussion gives you some idea of the trade-offs involved
> & the order of magnitude of the effects.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
> ----- Original Message -----
> From: "Steve Alm" <salm@mn.rr.com>
> To: <rhodes22-list@rhodes22.org>
> Sent: Friday, July 26, 2002 5:41 AM
> Subject: [Rhodes22-list] Hull Speed
>
>
>> I've owned my R22 for less than a year and I'm still learning a lot about
>> the boat and still learning a lot about sailing. First, what is the hull
>> speed of the R22? I know there's a standard formula to calculate this but
> I
>> can't seem to find it.
>>
>> Second, I have the IMF and the 175% Doyle genny. What's the approximate
>> minimum wind speed and optimum point of sail necessary to achieve hull
> speed
>> under full sail? I'm guessing a beam reach with winds at about 14-16.
>> Would it be easier with the boom in the down ("first reef") position? Can
>> it be done safely with the boom in the up position? Some of you have said
>> that you ALWAYS have the boom down unless it's very light air. (I prefer
> to
>> sail with the pop top up.)
>>
>> Third, without the standard main or a foam luff pad, is it possible for me
>> to pop over my bow wave and exceed hull speed? If so, under what
> conditions
>> could I safely do that?
>>
>> Sorry to sound like such a novice...I yam what I yam. I'd like to take
> some
>> lessons some day but in the mean time, I'd really appreciate a few sailing
>> tips from you experts.
>>
>> Anybody?
>>
>> Slim
>>
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>
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