Is this normal?

[An anonymous user]

Guys,
We had a wonderful time sailing in 15-20 kts winds last weekend. I noticed when we were sailing that the boat was not moving in the direction I had it pointed. With the winds off of the port side we were moving in a direction about 30 deg. off of the nose. This did not change with the keel up or down. So is this normal ? I know when I fly I have to crab into the wind to maintain a certain heading. Is this the same in sailing ?

 

[JRacer]

How flat were you sailing the boat? If you were "on your ear", rail in the water, you were undoubtedly slipping sideways because the keel wasn't in the water helping you to maintain a course. I am assuming that you weren't "pinching" into the wind and therefor not having much power to move you forward (lack of forward movement is also going to cause you to slip sideways). If you are not experienced, I'd suggest you invest the best hundred bucks you ever spent on a few sailing lessons - hope I'm not being presumptuous but your issue is not easy to diagnose without knowing your level of expertise. And, of course, current is also a factor (the equivalent of the need to crab in flying). But with the boat you are limited as to how much you can "crab" into the current by the fact that you can't turn into the wind above a close-hauled course. In which case, it seems like you need to tack!

 

[An anonymous user]

How flat were you sailing the boat? If you were "on your ear", rail in the water, you were undoubtedly slipping sideways because the keel wasn't in the water helping you to maintain a course. I am assuming that you weren't "pinching" into the wind and therefor not having much power to move you forward (lack of forward movement is also going to cause you to slip sideways).


We were maybe at a 15 deg heel. As my sailing experience is ... none... Im not sure what pinching into the wind is.:neutral:



If you are not experienced, I'd suggest you invest the best hundred bucks you ever spent on a few sailing lessons - hope I'm not being presumptuous but your issue is not easy to diagnose without knowing your level of expertise.

This is in the works for next year. I want to take the ASA keelboat class and the costal cruising class in Charleston this comming spring.

And, of course, current is also a factor (the equivalent of the need to crab in flying). But with the boat you are limited as to how much you can "crab" into the current by the fact that you can't turn into the wind above a close-hauled course

We were on a lake in SC so I dont think the current would be a factor.

The wind was 45deg. off of my port side and the boat was moving about 30 deg. off of the nose to port of the boat. I though it might be that the keel was causing this so I raised the keel and there was no change.

I do have to say I was pleased that both my wife and I managed to make the boat go around a small Island 3 times. While I was "Tacking" the boat, was when I noticed this situation.

Thanks for your reply.

 

[JRacer]

No problem. If you are a pilot, the aero/hydro dynamics are similar so grasping the airfoil/hydrofoil issues will be easy. If you are a pilot, just think of the sail trim in terms of angle of attack. If the angle is too acute to the wind, it's not efficient. If you are slipping sideways, I suggest you dump the main (release the sheet) then slowly trim it back in until you start to move. Once there, two choices, leave the trim there and steer that course or head (the boats head ) up into the wind a little and trim the sail in to account for the course change. Whenever you aren't sure it you are trimmed in too much (sail looks ok but is stalled) or not trimmed in enough (sail will be flogging), just let the sail out until it flogs a little and then slowly trim it back in. Your telltales on the sail can tell you if things are flowing - if the tell's are flowing back then you have airflow. if they droop, they are stalled.

May I recommend you get this and read it.: http://www.amazon.com/Sail-Power-Complete-Guide-Handling/dp/0394727150

And do get the sailing lessons. The gain per buck/hour spent will be tremendous. Even now if you just pay an experienced guy in the short term to go out with you for an hour or so. You will gain a ton.

Pinching is where the sail is set to a given trim point but you are steering closer to the wind than the sail is set. When you do that, the sails will be trimmed in but you will be "back winding" them. The boat will flatten out but will be slow and you will get excessive side slip vs forward movement. Solution is to "bear off" the bow (turn it away from the wind) or if possible trim the sail in some more. Always a compromise between course and sail trim angles - think angle of attack.

 

[MrBill_FLL]

a windex might be a good and relatively cheap addition.

it really helps me know where I am on a point of sail, and where the sails should be trimmed. and VERY useful downwind, avoiding jibes.

(the don't sell the model I have any longer(removable) so you'll need to put a string on it when towing so it doesn't windmill to death...)

http://www.sailcare.com/wind-indicators.shtml

some slip is normal, but you describe excessive slip.


and pls confirm your boards were fully down.

 

[Sumner]

....some slip is normal, but you describe excessive slip......and pls confirm your boards were fully down.

We never noticed the slip a lot on lakes as our position wasn't critical, but did notice it in Florida both with the sails up and/or running with the outboard and it was caused by wind and current and possibly because we didn't have our CB all the way down when on the outboard.

When we were on the ICW with a lot of water on both sides, but most of it shallow and the marked channel was narrow you could pass one channel marker and then head to the next and look back and the one you passed wasn't behind you, but off a ways to the side. You then had to crab the boat to stay in the channel.

Ruth had some problem in that she wanted to point the bow at where she was going and that just doesn't work if the current is taking you sideways at the same time or the wind. Also when you are sitting offset on the side of the cockpit and looking at the bow you aren't on the centerline so it doesn't work either. I finally got her to look down the side of the pop-top and use that as a sight and that worked better. Still if you are in a narrow channel and are sharing it with boats coming towards you and others passing you one needs to constantly be looking back at the last marker they passed and then forward to make sure you are where you need to be.

Stilll after a while you start to feel where the boat as a whone is going and not the bow regardless of the amount you are crabbed which can be considerable crossing a cut at 90 degrees to the tide coming in.

Izzy sailing on lakes in the west we didn't notice the problem much, at least not to the point that you mentioned so I try some of the solutions the other guys mentioned and we will keep them in mind also.

Added later: The times we noticed the wind effecting us were when it was above 15 mph as you indicated. Almost any current is noticeable. Also I think our boats probably have more slip than we normally notice when sailing in open water with nothing close to us directly ahead and astern like the channel markers to clue us in to the fact,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

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[timebandit]

It seems strange that it was the same with the keel up????

 

[thomasgoodmaniii]

could rig tension or mast rake have any effect

 

[Faris]

Some of this has been touched on, but ...

• Keel down will reduce slipping. This is a big part of its job. The higher up into the wind you are sailing, the more you want it.
• You shouldn't really sail upwind in 15-20 with your keel up. Its other job is that it keeps you from tipping over in such conditions.
• The 26 slips - it just does. It shouldn't slip 30 degrees, but you should expect maybe 10-15 degrees in those conditions.
• The faster you are moving forward through the water, the less you will slip sideways with your keel down. This gives us a clue as to your problem.
• My guess is that you had some heavy rudder action? Probably weatherhelm, i.e. the tendency for the boat to want to turn into the wind which you have to counteract.
• Weatherhelm or no, definitely what you were doing with your sails contributed to the problem.
• Part of the problem is that slipping is self-perpetuating. That is, the faster the keel moves forward the stronger its resistance to sideways slippage. However, sideways slippage reduces this forward speed, and to keep the boat pointed the direction you want to go, you counteract with rudder, which slows you down, which contributes more to slippage, which ... you can see the cycle.
• It is all correctable with proper sail trim. I'll be almost anything that you had everything sheeted in too tight, particularly your main. This is a common mistake since it makes you feel like you are going faster. It's an illusion generally.
• You don't really need a windex - just fix a telltale to each shroud. That's enough, though I windex is better. Look at the windward telltale. It shouldn't point less than 45 degrees (approximately) off your bow.
• Sails should be pulled in just to the point they no longer luff (as explained above). This position will change as the boat picks up speed and the apparent wind changes. Contrary to popular belief, this is not the fastest sail trim in all boats, but it is close enough, and is easy to find.

Enjoy.

 

[chp]

I have found on my Mac sometimes the keel does not go down if there is side pressure on it. It wedges in the trunk until I either head up more or bear off to take the pressure off. Check to make sure there is no slack on the keel rope. This usually happens when I single hand in strong winds and I'm busy or with someone on the helm who doesn't understand what is going on.

 

[doehunter]

When compared to a fixed keel boat, our swing keels are tiny!
Couple that with the thin crossection and it's easy to see why they slip a little.
Technically speaking, they all do. Just like on an airplane, a symmetrical airfoil will not provide lift if it's at 0 angle of attack. The wing has to be pointed up a little. Thus they crab too, just up instead of sideways.
The good thing is that they are big enough for us to be able to sail anywhere we want to go, and will still swing up into the hull and allow us to go where they cannot.
Jim