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indecentseas
1st Mate

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Canada
67 Posts

Initially Posted - 03/05/2013 : 14:52:12

I'm new to keel boat sailing and I want to get a better sense of my boat's performance. My boat is a 1978 Catalina 25 with a drop keel. I do not know the age of the sails. They look worn, and may be original, but there are no holes or other obvious problems.

One frustration I have is that I really have to fight the tiller to keep the boat from slipping into irons when I am trying to sail upwind. When the wind gets over 10-12 knots it takes some real effort, with my rudder about 30 degrees off center, to force the boat to stay on track. The boat just wants to lean over and slip the bow upwind.

Does it sound like a problem I should be able to solve through better trimming of my sails or is this just a part of life on a keel boat? I'm used to sailing Hobie cats and other smaller craft. Those boats, when properly rigged, require no effort to keep a straight course through moderate to heavy winds.

A related question is cruising speed. In a nice breeze like 15 knots, going upwind, my boat develops quite a lean and only goes at about 4 knots, possibly 4.5. I feel the boat should attain a cruising speed of about 6 knots in a good wind like that. Am I being unrealistic or does my cruising speed also suggest I need to learn more about trimming my sails.

Cheers,
-David Hopkins.

David Hopkins
Vancouver, British Columbia
'78 Swing Keel, Standard Rig, Dinette
#534

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/05/2013 : 18:52:20

Generally, a keel boat with a properly tuned rig and well-trimmed sails should have a light helm. If you are experiencing a consistently heavy helm, it is likely that the sails are poorly trimmed, the rig is not well tuned, or the sails are out of shape, and I would look for the most likely cause in that order.

A windspeed of about 10-12 kts is capable of generating all the power that a 25' sloop needs to sail at about 6 kts. When the windspeed is below 10-12 kts and boatspeed is below hull speed, the objective is to trim the sails so they will generate more power. When the windspeed is above 10-12 kts, then the objective is to trim the sails so they will generate less power.

A keel boat has a displacement hull. A displacement hull is said to be "easily driven." That means it doesn't generally take a lot of power to drive it through the water up to it's designed hull speed. However, it takes an enormous amount of power to make the boat go faster than its designed hull speed. What that means is that, as the boat approaches hull speed, the resistance created by the water increases. When the sails are generating excess power, and the boat is at hull speed, that excess power has to be released in some way. The consequence is that the boat heels more. (When the boat heels, some of the air spills out of the sails, which bleeds off some of the excess power. Also, when the boat heels, the keel becomes less efficient and the boat slips sideways, which also bleeds off power.) But, when the boat heels excessively, the shape of the hull's wetted surface changes in ways that are not helpful. A sailboat that is heeling excessively is generating turbulence as it moves through the water, and that turbulence is drag. So, when a sailboat is overpowered, it heels excessively, and that increases the resistance that is operating against it.

The solution is to learn to trim the sails so that they are generating the correct amount of power for the amount of wind that is present. As the windspeed increases above 10-12 kts, you can gradually decrease the power of the sails by trimming them with a flatter shape, but there will be a point where you have depowered them as much as you can by trimming the sails. At that point, your next logical step will be to reduce the sail area.

It's also possible that your rig needs to be tuned, or that your sails are old and baggy, but an out-of-tune rig or baggy sails aren't likely the cause of the extreme amount of weather helm that you have described. Nevertheless, If the sails are nearly as old as the boat, they can't have much useful life left in them, and you will probably want to replace them. If you do, resist the idea of buying cheap sails. Some of our members can refer you to sailmakers who will build good quality sails for you for just a little more than the price of the discount sailmakers.

You can find some guidance here on rig tuning. http://catalina-capri-25s.org/racing/racing_tips7.asp

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9081 Posts

Response Posted - 03/05/2013 : 20:28:36

On the subject of rig tuning, the primary "tuning" factor that affects "weather helm" (the boat trying to turn into the wind) is the rake of the mast. Most of us have found that the C-25 wants the mast to be raked back no more than about 6", meaning if you put a weight on the main halyard and hang it at boom level, the weight won't be further than that behind the mast. But I'm suspicious that's not your issue--to me it doesn't explain 30 degrees of weather helm, which is heavy drag on the boat as well as on your arms!

35-year-old sails (if that's what yours are) are likely to be more like balloons than like airfoils--particularly the main. While the out-haul, vang (if you have it) and cunningham (less likely) can pull the the foot, leech, and luff of the sail tight, if it's "blown out", the area in the middle is a big bag that wants to catch the wind, hold it, and push the boat over instead of driving it forward. Because that push is aft of the keel, it tries to swing the stern to leeward and the bow to windward, while not providing the drive you should be getting from a shape that smoothly deflects the air aft.

The headsail has some of the same issues, although the diagonal pull of the sheet is generally somewhat more effective in flattening its shape even if it's stretched out. And its center of area (and therefore center of effort) is lower than the main, so it contributes less to heel. So if you decide it's time to upgrade but the budget is an issue, I'd suggest starting with the main.

Your symptoms are classic for "balloon sails"--I'm fairly optimistic a new main, in particular, will feel like a new, fuel-injected engine, re-aligned wheels, and new shocks in a 1978 car. A hew headsail will add some more drive up-wind, but the improvement won't be as dramatic. In anything over 10 knots of wind, you should be doing 5.5+ to windward with a light (5 degree) weather helm. (The theoretical maximum "hull speed" is about 6.3 knots, past which the bow has to lift over the bow-wave, which can happen on a beam or broad reach.)

We'll be waiting to hear about the exciting improvement!

(Remember: B.O.A.T. = Break Out Another Thousand.)

Edited by - Stinkpotter on 03/05/2013 20:41:17

redeye
Master Marine Consultant

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3476 Posts

Response Posted - 03/06/2013 : 08:43:45

Tighten up the topping lift and let the main out some. This will reduce some of the heeling and your weather helm.

You are probably closing your leech on the main.

Edited by - on

indecentseas
1st Mate

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Canada
67 Posts

Response Posted - 03/06/2013 : 09:08:47

Thank you all for your advice. I can probably play around with my sail a bit but I think Dave diagnosed it correctly: My sail is a big old windbag. Time for a new one. Steve, thanks for pointing out the racing tips page. I had missed all that content.

Edited by - on

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/06/2013 : 17:25:32

If you are rounding up consistently, your sail plan/rig is out of balance for the conditions for any of the reasons mentioned previously. To illustrate helm response, this video is one I took while close hauled in winds around the mid-teens. I'm sailing with a full main and genoa. Notice the tiller is around centerline.

[url="http://www.youtube.com/watch?v=6usNpNN9h0w"]Autopilot[/url]

Edited by - on

glivs
Admiral

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USA
836 Posts

Response Posted - 03/06/2013 : 18:21:15

Lots of good advice and the most probable causes have already been identified. Just to ensure all possibilities are covered, however, what sails are you using? If by chance you are flying a storm sail as a headsail with a full or possibly even single reefed mainsail the center of effort would be forward of the mast and the boat would handle as you describe. More likely as already mentioned there are multiple factors contributing. To add to the list, your rudder also functions as a foil and the older design tended to have a bit of weatherhelm so I'm told. However with a "balanced" rudder and a balanced sail plan these boats sail effortlessly as Don shows in his video.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9081 Posts

Response Posted - 03/06/2013 : 20:57:01

The balanced rudder doesn't change the helm--it just changes the effort to maintain it. If you need 5 degrees (or 20 degrees) tiller angle to offset the weather helm of the boat, the balanced rudder just assists you due to the pressure on the blade forward of the pintles offsetting the pressure aft of them. It's a little like power steering--however, if you have heavy weather helm, it's like power steering on a car with a mis-aligned front end. On the boat, it will slow you down due to the drag. On the car, it will rip up your tires and eat gas.

The helm should be a few degrees "to weather", as Don's clip shows, regardless of the "balance" of the rudder itself. If it's zero degrees, then it's considered "neutral", which means if you let it go or fall overboard, the boat will just sail off into the sunset. If it's a few degrees in the other direction ("lee helm") and you let go, the boat will jibe. I'm not a fan of either. And racers tell me a little weather helm makes the boat faster.

Edited by - Stinkpotter on 03/06/2013 21:00:43

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/07/2013 : 07:00:22

My suspicion, David, is that it is an oversimplification to attribute your exceptionally heavy weather helm to one cause, such as your old sails. I think it's much more likely that it is being caused by multiple factors. If you replace the sails but don't tune the rig or improve your sail trim, you might still be disappointed with the performance of the boat. As Dave correctly observed, the balanced rudder became popular because it made the helm pressure feel light, and it gave the illusion of a well-tuned rig without actually having to tune the rig.

What makes your boat fast is to reduce drag (resistance) to a minimum. Sailing overpowered creates drag. Excessive heeling creates drag. A badly tuned rig, which results in an imbalance between the pressures on the sails and the pressures on the underwater surfaces, creates drag. I always liked to imagine that, when I felt unusual tiller pressure, the boat was trying to talk to me. It was the boat's way of telling me that it wasn't a happy boat and sailing free, and that I needed to do something to reduce that pressure and make her happy. If I added a little tension to the jibsheet or jib halliard, or to the mainsheet halliard or outhaul, or eased the mainsheet a touch, and, if that reduced the tiller pressure, then that told me clearly that I had reduced drag, and that the boat would sail faster and point higher.

A heavy weather helm isn't endemic to a C25. Adjustments can be made to reduce it to a minimum. Whenever you feel it in the tiller pressure, try making different sail trim adjustments until you find one that reduces the pressure. Excessive weather helm isn't only a challenge for new sailors. The most skilled racing sail trimmers will be frequently asking their skippers whether they are feeling excess pressure in the helm, and will make sail trim adjustments accordingly in an endless effort to reduce drag to a minimum.

Edited by - on

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/07/2013 : 07:41:58

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 The balanced rudder doesn't change the helm--it just changes the effort to maintain it. <hr height="1" noshade id="quote"></blockquote id="quote">

I dunno. If the balanced rudder has improved lift characteristics over the original, it has to affect performance as well, and not just in the measure of tiller pressure. I've only had a balanced rudder so I can't give a reasoned opinion one way or the other, but Derek once said...(the emphasis in the text below was his, not mine)

"With the original rudder, in 10k or more I had the tiller pulled under my chin there was so much weather helm. I installed the balanced rudder and WITHOUT CHANGING THE TUNING OF THE RIG had 2 finger steering in ANY wind." - Derek Crawford

I take this to mean after Derek installed the new balanced rudder, his severe weatherhelm in over 10kts of wind went away.

I'm tempted to temporarily swap my balanced rudder with an original rudder from one of my C25 friends in my marina then use it like I normally would so I could see the difference for myself. The wind in that video I posted earlier was more likely in the upper teens, maybe close to 20, with full sails. With Derek's observation in mind, I'd imagine with the same set up and an original rudder, severe weatherhelm would kick in and my tiller would be under my chin (hard to windward).

Edited by - on

Stinkpotter
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Djibouti
9081 Posts

Response Posted - 03/07/2013 : 08:52:25

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dlucier
 I'm tempted to temporarily swap my balanced rudder with an original rudder from one of my C25 friends in my marina then use it like I normally would so I could see the difference for myself...<hr height="1" noshade id="quote"></blockquote id="quote">With the almost neutral helm shown in your video, I'll speculate you won't experience much difference on a straight course--you'll feel it when tacking or adjusting course. I had the original, unbalanced rudder for my first couple of years, and replaced it with the fiberglass balanced blade from CD, which is apparently the same as what Catalina changed to around 1988. It did indeed make steering a 2-finger affair, and my slight weather helm (2-3 degrees) a one-finger thing. It also eliminated some flutter--probably due to the NACA foil shape that reduces turbulence. That should also increase lift--but just a little bit. (This is at ~5 knots, not 500.)

If the change for Derek was as you're surmising, his boat would've gotten a lot faster, too. But I think This Side Up was already smoking everyone on the lake with the original, so I suspect it was more of an effort improvement than a performance improvement. Maybe his ears are ringing now and he'll tell us.

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/07/2013 : 09:15:10

None of us have scientific proof to support our thinking. Each of us can only offer our observations, based on our own experiences, and others have to compare that with their own experiences to decide which opinion to accept.

I've had both the original 1981 rudder and the balanced rudder, and my well tuned rig gave the boat very light tiller pressure with the original rudder. When I switched to the balanced rudder, I didn't feel a noticeable lessening of the tiller pressure, because it was already very light to begin with.

Don, I think you are giving more credit to your balanced rudder than it deserves. Your video shows enough of your sails to demonstrate that your sails are flat and smooth, and are thus very nicely trimmed and shaped for the windspeed and direction in which you're sailing. I also believe that a sailor with your long experience has also tuned his rig at least fairly well. With such good sail trim and rig tuning, I think your boat would have a light helm, regardless of whether it had the original or the balanced rudder. It isn't the rudder that made that light helm happen. It's the sailor.

Edited by - Steve Milby on 03/07/2013 09:15:44

PCP777
Master Marine Consultant

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USA
1225 Posts

Response Posted - 03/07/2013 : 11:40:26

Other than everything mentioned above, make sure you don't have too much sail up for the conditions. That will over power the boat, produce weather helm, heel the boat excessively and slow the boat down. Do whatever you can to flatten the main, hammer the outhaul, the cunningham if you have one and make sure the sail is ALL the way raised with the halyard. Even with my old blown out main sail I was able to do pretty well with the rig tuned and the sail properly set up and trimmed in winds from 12 to about 18 without reefing.

Edited by - on

Boomeroo
Navigator

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Australia
129 Posts

Response Posted - 03/15/2013 : 04:29:17

Regarding the speed to windward ,I think 4.5 would be very good if hard on the wind , pull away 20 deg and 6 -7 kn is fine. I race an etchells (30Ft)on Saturdays and use a speed puck to tune up prior to a race and 6 Knots is a good target to windward in 10+ knots
The same puck on the C25 reads just over 4 Kn hard on a breeze .
Being a GPS device in no tide it is accurate Cw our old paddle-wheel speedo,s which always read faster.

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/15/2013 : 07:04:44

In these discussions, it's probably good to take any reports of specific speeds with a grain of salt, because we sail in different venues with different conditions. For example, a sailboat can generally make better speeds to windward on a small inland lake than on a big bay, because it won't be affected nearly as much by chop or by currents. I never had a knotmeter on my C25, because I never particularly cared what speed my boat was going, so long as it was going faster than the boat next to me, but I know that, in the autumn, when most of the powerboaters and water skiers were gone and the water was glassy smooth, my boat generally made far better speeds than when it was affected by chop. Because the conditions where each of us sail vary so widely, and because speed instruments and guesstimates are often of questionable accuracy, it's probably best to think in terms of maximizing boatspeed on any point of sail, rather than talking in terms of specific boatspeeds. Besides, I can't think of any other means of transportation where you can have so much fun at less than 10 knots.

Edited by - on

redeye
Master Marine Consultant

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Response Posted - 03/15/2013 : 11:43:19

I spent last weekend on one reach sailing with the tiller tied in one spot and changed my heading by pulling in or out the mainsheet.

What does that tell you about creating weather helm with the main?

You can set the main loose, and tighten up the jib ( the 135 I think ) and the boat becomes self correcting, if it falls off the main begins to get pressure on the trailing edge and it turns up, if it turns up too much the jib luffs and it falls off.

Get it balanced out correctly and the boat picks up speed in the blows, rather than changing direction with each change of wind speed.

I don't get to do that often, only with the wind out of the east and relatively steady. Coming off flat land the water is relatively flat with little reach.. it is a hoot.

Edited by - on

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Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
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