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Bruce Baker
Captain

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USA
402 Posts

Initially Posted - 06/10/2002 : 10:58:49

What are the merits of sailing in light winds with the keel up / down?
I would think that you're faced with a tradeoff of more sideways drift (up) versus more drag (down). Does anybody have a view as to the relative importance of each?

In heavier breeze, you would obviously sail to windward with the keel down. What about downwind? Do you pull the keel up as you would in a dingy?

Finally, is there any condition where it would be better to sail with the keel half-way down?

Thanks,
Bruce Baker
"Yee Ha" 3573

Edited by - on

Steve Milby
Past Commodore

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USA
5913 Posts

Response Posted - 06/10/2002 : 12:31:49

Bruce,

The Catalina 25 Class Racing Rules provides:

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Retractable keels shall remain in the down position unless the safety of the crew or boat requires otherwise. The cable may be removed or attached along the trailing edge of the keel. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Therefore, if you are racing, you are required to keep the keel down in all circumstances, unless safety requires otherwise. I think the "safety" exception will probably be strictly construed and applied.

I don't think it is generally a good idea to sail with the keel raised, for two reasons.

First, swing keel C-25s on my lake have tried it, and it doesn't make any significant difference in the speed of the boat. Whether the keel is up or down, there is very little difference in the amount of wetted surface that is exposed. When you raise the daggerboard on your dinghy, you actually reduce the wetted surface of the keel, by raising the daggerboard out of the water. When you raise the keel on a C-25, it pivots up against the bottom of the boat, but the entire keel is still in the water, and the amount of wetted surface remains the same. Therefore, by retracting the keel, you do not significantly reduce the amount of drag.

Secondly, the boat is not really designed to carry the weight of the keel in the "up" position. As you know, when it is on the trailer, you should release the tension on the keel, and let it rest on the trailer frame, so that, when the trailer goes over bumps in the road, it doesn't put excess stress on the structure of the boat. Bouncing over waves puts similar stress on the supporting structure of the retracted keel as if the boat was riding on the trailer with the keel retracted. Depending on the condition of the keel-raising mechanism and the cable, there is a risk that the mechanism might suddenly break, dropping the keel, and seriously damaging the structure of the boat. I have known people who have sailed with their keel partially raised for many years, because the depth of their lake is very shallow, and they have had no problems, but it should be avoided. It's one thing to take a chance where there is a risk of minor damage to the boat. It is another thing to take a chance where there is a risk of catastrophic damage to the boat, even if the likelihood of occurrence is fairly slight.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>is there any condition where it would be better to sail with the keel half-way down?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Yes. When the water is only about 2 1/2 feet deep.

Steve Milby "Captiva Wind" C-25 T/FK #2554

Edited by - Steve Milby on 06/10/2002 15:59:30

Edited by - on

Derek Crawford
Master Marine Consultant

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USA
3324 Posts

Response Posted - 06/10/2002 : 17:48:52

Bruce - you should also check with your local PHRF Committee - most of them have a prohibition against raising the swing keel. Not only is it a safety precaution (speaking as one who sank a swing C22...) but it levels the playing field between the swing keel,which is faster upwind and the fixed keel which is faster downwind. If you are allowed to speed up downwind by raising the keel, then you need a different rating! Ensuring that the swing keel remains lowered is why the PHRF ratings are the same for both models.
Derek Crawford C25TRFK
Chairman, PHRF Committee
Canyon Lake, Texas

Edited by - on

Gary B.
Admiral

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USA
969 Posts

Response Posted - 06/11/2002 : 11:09:04

You're right for the Catalina National Association races, but my local race people have told me "all's fair" with the swinger. Although I don't raise it, I could, according to them....

Gary B. Encore! #685 SK/SR

This is a PHRF fleet, not a "racing level" fleet association.

Edited by - on

Derek Crawford
Master Marine Consultant

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3324 Posts

Response Posted - 06/11/2002 : 12:51:58

Gary - how does your PHRF number compare to a C25 SRFK? And what does your local assocn. rate the TRFK and the TRSK?
Derek

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 06/13/2002 : 09:01:02

Derek: Can't answer the question on TR, but the SK rates 238 with a spinnaker, 259 or so w/o. I got rated for an asymmetrical chute this season: 247. Most of the Cats around here are swingers/ a few fixed, but few tall rigs so I don't know their rating.

I looked all through the Pacific Northwest PHRF book and don't see a C-25 with a rating faster than 238 (there are only about 4-5 or so in the book with certificates), so I assume no TR. They'd have to rate faster with more sail area....

I can't tell from the book which are swingers and which might be fixed, but around here, I THINK they rate the same.

Gary B. Encore! #685 SK/SR and Suede Shoes #496 (for sale)

Edited by - Gary B. on 06/13/2002 09:04:15

Edited by - on

Champipple
Master Marine Consultant

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6855 Posts

Response Posted - 06/13/2002 : 15:03:58

8 Reasons not to hoist it up. (and I used to be an advocate for raising it..)

1. No discernable difference in moving the keel weight 4 feet aft. (that is roughly the net result of what you are doing...
2. You only reduce the wetted surface by about 1.5 ftsq if your lucky
3. Your gonna forget to put it back down on the upwind leg or better yet, your gonna have someone cranking it down at the same time the spinaker is coming into the cabin on the takedown and its all gonna go south in more than one piece.
4. You aren't going to capsize like a small thistle or daggerboard boat...
5. Its a pain in the dupa
6. One design rules don't allow for it.
7. Most PHRF organizations won't allow it...(although some are stupid enough that you can convince them it is the same as a boat with a centerboard. and will allow it)
8. You aren't going to go any faster...believe me.

When should you raise it.....When you are in a really shallow area.

and definitely don't raise it just because you are motoring...1. you won't go faster and 2. on a windy day you will slip and slide any way but forward.

dw

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 National Assn.
<img src="http://im1.shutterfly.com/procserv/47b1ce23b3127cce9b043565af3d0000004010" border=0>

Edited by - on

Derek Crawford
Master Marine Consultant

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3324 Posts

Response Posted - 06/23/2002 : 11:01:47

Gary - sorry for the long delay but I've just got back from crewing in the C22 Nationals on Galveston Bay.
All of your PHRF numbers for the C25 are very high compared to ours - they should be a license to steal!! We rate TRFK/SK at 221 and the SRFK/SK at 225 - whether you run a chute or not.
Derek

Edited by - on

Gary B.
Admiral

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USA
969 Posts

Response Posted - 06/24/2002 : 03:14:18

You better come and crew for me, then, Derek! Even with that rating I can't compete with the go-fasts at all! Even the Cal 20s, which rate at about 290 always beat me on handicap. I'd be curious to know what other boats rate in your area. An Olson 30 here rates about 99, a Tartan 30, 197. How do those sound in comparison??? It's the difference that counts, I assume, not the actual number of each, right?

Gary B. Encore! #685 SK/SR

Edited by - on

Derek Crawford
Master Marine Consultant

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Response Posted - 06/24/2002 : 14:13:14

Gary - it appears that all your numbers are higher than ours. We rate a Cal 20 @ 270 (same as a Catalina 22), an Olson 30 OB @105 and the Tartan 30 @ 177.
It is the differential in numbers that counts - if you rate 260 and someone else rates 220 - he owes you 40 seconds per mile of race course. If it's a 5 mile course he has to beat you by more than 200 seconds to still win on corrected time.
Derek

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Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 06/24/2002 : 17:18:25

So lets race 1983 TR/FK Tacoma Wa.

Doug&Ruth
Wind Lass
Tacoma Wa.

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Brooke Willson
Admiral

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USA
983 Posts

Response Posted - 06/25/2002 : 19:44:21

This doesn't really address the racing issue because of the rules, but there's absolutely NO question that when "Even Chance" (1985 SKTR #5050)is coming in or out of port under power, she moves from one half to a whole knot faster with the keel raised. I don't think it's a matter of wetted surface. . . it's a matter of drag. A raised keel presents much less forward edge to the water, so it requires less power to overcome the drag of the water meeting the keel. Also, there's less turbulence in the wake of the lifted keel, which would also create drag.

Whatever the physics are, the speed change when I lift the keel is obvious and documentable.

In my 17' Mobjack racing sloop, the clear racing instructions were to raise the keel going downwind to increase speed. Of course in that boat the keel came completely up into the hull.

Brooke

Edited by - on

Derek Crawford
Master Marine Consultant

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Response Posted - 06/26/2002 : 01:01:44

I have to agree with Brooke. I have no experience with a C25 swinger, but on our late-lamented C22, if we raised the keel going downwind you could watch the knotmeter go up (this was when we could raise the keel while racing). Strangely enough, the optimum speed was achieved with the keel half raised.
Derek

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 06/26/2002 : 11:21:51

I just have to weigh in again. Logic says this should be so, but, honestly, I have tested this so many times my arms are sore from cranking....I have NEVER seen the knotmeter go up when the keel is raised, motoring, or under sail. In fact, if anything, I go faster with it down. Since I'm always in current here on the Columbia, or in tidal waters, there are variables, certainly. I don't dispute your evidence, but mine is clearly different. I am beginning to wonder if the placement of the knotmeter makes a difference, in that keel turbulence might be affecting one or more of us. My knot meter impeller is in the flattest part of the boat, just aft of the keel slot on the starboard side. Certainly, it's close to the aft end of the keel when its raised. Could this be a factor that is causing apparent differences? The GPS might help to check this, but it's always higher or lower than the kM, cuz I'm going with or against current. Whaddya think?

Gary on Encore! #685

Last weekend the GPS read 4-4.5 while coming up a very high river. KM was over 7 with Yamaha 9.9 wide open...(t'was still a 7 hour trip home from a race. I flew the chute, too, when there was enough air to fill it....)

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Brooke Willson
Admiral

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USA
983 Posts

Response Posted - 06/27/2002 : 15:46:52

I don't have a knotmeter: my only way to measure speed is with the GPS and the gurgle of the wake. Both say the boat is faster with the keel up.

I haven't tried half-way down/up.

On my Mobjack, the instructions were centerboard down close reach to beam reach, board halfway up on broad reach, and up for a run.

Brooke

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Steve Milby
Past Commodore

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USA
5913 Posts

Response Posted - 06/27/2002 : 18:32:14

I agree with Gary. I've raised and lowered the swing keel on a C-25 with a knotmeter, and found no difference in speed. Obviously, whatever measuring devices we use are subject to some doubt. Duane's list of 8 reasons not to do it is pretty persuasive.

Steve Milby "Captiva Wind" C-25 T/FK #2554

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Brooke Willson
Admiral

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USA
983 Posts

Response Posted - 07/03/2002 : 14:19:10

For what it's worth. . . as soon as I can, I drop my keel and leave it down until I'm coming back to port <img src=icon_smile.gif border=0 align=middle>.

Brooke

Edited by - brooke willson on 07/03/2002 14:20:31

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Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 07/03/2002 : 22:02:11

Sure glad I have a Fin keel and dont have to worry about up or down. Everyone knows the fin Keels are faster over all.

Doug&Ruth
Wind Lass
Tacoma Wa.

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Derek Crawford
Master Marine Consultant

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Response Posted - 07/04/2002 : 00:43:17

Doug&Ruth - I'm not sure that the fin keel is faster overall. I've just returned from the C22 Nationals - and those hardcore racers won't even consider a fin keel for racing! Out of 34 boats there was not one fin... I do know that the swing (even on the C25)is faster to weather and (provided you leave it down!) slower off the wind. That's why we rate them the same in PHRF.
Derek on "This Side Up" C25 TRFK

Edited by - on

Douglas
Master Marine Consultant

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Response Posted - 07/04/2002 : 11:58:24

I was just trying to stir up some interest here in the Sound. Like come on over to my pond and we will race. The C-25 sailors here are way to laid back. Im just funnin. I do envy the fact that the swingers can make it north to the islands in a few hours. It takes me 3 days.

Doug&Ruth
Wind Lass
Tacoma Wa.

Edited by - on

Bruce Baker
Captain

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USA
402 Posts

Response Posted - 07/09/2002 : 15:09:31

To answer my own question, the boat is unquestionably faster downwind with the keel up. We may be talking a couple tenths of a knot, but I was in a close race with an O'Day 22 that was catching me slowly from behind. When I pulled up the keel, I left him in the dust.

After reading the rest of the replies, I need to find out if I was cheating:) Not that it mattered.
Bruce Baker
"Yee Ha"

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 07/10/2002 : 10:53:22

I've got a 30 mile run to do tomorrow up the Columbia into a 2-3 knot current. I'll try it again...and again...although I will most likely be powering much of the time. Race on Fri. and another long distance race Sat. to Sunday A.M. (possibly) If it really makes a difference, I want to know it. Will check with KM and GPS...again...to see...
Gary B. Encore! #685 SK/SR

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 07/12/2002 : 01:52:51

Okay....maybe it helped to raise the keel under power and downwind, but there are variables with the current of this river. Whatever it may be, it certainly did not seem to be more than .1 knot on this boat. It really didn't register with the KM, but GPS averages out the speed more. It MAY have picked up about .1 My friend who was along for the ride felt that it was inconclusive.....and 1/2 way seemed as good as anything.....Gary

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Derek Crawford
Master Marine Consultant

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USA
3324 Posts

Response Posted - 07/12/2002 : 11:26:51

Personally, as a hardcore racer, I think .1K is significant. That's .17 feet per second faster. Assuming a 1 hour race (just as an example) with 1/2 of it downwind, that translates to .17 x 60 x 30 or 306 feet which is just over 12 boat lengths! I would take that advantage anytime (just wish I could!)
Derek

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 07/12/2002 : 11:42:47

You're so right, Derek, as usual....It was just hard to measure out there without a second boat. Now I know why the AC guys always have two boats to test with. I am trying hard to get a one design fleet out here so we can compete with each other.

I am certainly not a "hard-core" racer, yet. My inventory is not new, all dacron, etc. I am just trying to get my boat to perform up to its potential, given the limitations I am under...some of which are $$$.

I got an asymmetric chute this spring...mostly because I do not have a steady crew for racing...often I go out with novices and have to watch everything myself 'cuz they don't know sail shape, etc. But, hey, we usually have a ball, and once in awhile we sail pretty well with the boats that rate near us. You can bet that I WILL be cranking her up 1/2 way at least downwind. I think it might actually help her "track" a little better. Yesterday, we had a good breeze 15/20? into a pretty good 2-3 knot current on the river that made for good sized waves. The boat rolled enough that keeping the chute flying on a run was tough and I eventually took it down and sailed between 5 and 7 with a poled out gennie. Wouldn't you think I'd be better off trying to reach downwind with an assymetric?

Thanks for all the advice...you're proving to be correct, although for cruising, I will leave my keel down all the time, I think...for a variety of reasons.

Hope Canyon Lake is settling down; NPR has given you some press, and I feel more "connected" to Texas flooding now that I "know you" through this website.

Best wishes, and fast sailing,

Gary on Encore! #685 SK/SR

Edited by - on

Derek Crawford
Master Marine Consultant

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3324 Posts

Response Posted - 07/12/2002 : 15:47:23

Gary - many thanks for your kind comments. Hopefully we will be able to race again before Christmas!<img src=icon_smile_sad.gif border=0 align=middle>
If you are racing with a novice crew, may I offer the following:-
1. Never, EVER, yell! (Unless it's to say "Heads Down!" when tacking).
2. Tell 'em what you are going to do long before you are going to do it. (e.g. Coming up to a mark, explain how you are going to round it and what you will do as you leave it - harden up and keep trucking or tack away)
It's been my pleasure to introduce several people to racing - including an all ladies crew...but that's another story! I have one "instruction" for them when they step onboard: "if you don't have fun, you are not invited again".
I can't help you with the chute. After two horrendous episodes with one (on someone else's boat) I vowed never to run one on "This Side Up". Quite frankly, I'm not impressed with the better performance of a chute on a C25 over using a poled-out 155% genoa. (That will probably start another discussion...)
Have fun!
Derek

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