Leaning over Rule

[Jim@sea]

A 24ft sailing boat we have on a lake does not have a paddle wheel speed & distance log, so when its blowing a bit the boat leans over to the point here the keel wants to come out of the water.
Is there a "rule of thumb" where say once a boat heels over to say 20 degrees it starts to slow down
I have never before sailed a boat without an indication of speed.

 

[Tranona]

No "rule" as far as I am aware (ready to be flamed!), but 20 degrees heel is pretty commonplace and for modern boats depending more on form stability considered optimum. However on older, narrower style boats greater angles of heel are possible as this increases the waterline length as the overhangs immerse and therefore the speed potential. Excessive angles of heel could result in boat slowing if caused by over canvass, rounding up and excessive weather helm.

 

[TernVI]

A lot of dinghy racers will tell you the magic angle where inefficiency starts is about 2 degrees.

For a yacht where the heeling generates the righting moment, it's obviously more subtle, but IMHO it varies significantly from boat to boat.
And in one designs, even from helm to helm IMHO.
Part of the question is 'Do you need to use a lot of rudder because you are heeled?'
If you can balance the rig while heeled, you can get away with more.

 

[AntarcticPilot]

It depends totally on hull-shape, as others have said. 1920's yachts were designed to heel a long way and were faster when so heeled, because the long overhangs meant that the waterline length was much greater when heeled than when upright. To bring it more up-to-date, my father's Halcyon 27 with a classic wine-glass cross-section heeled until the lee rail was in the water, and simply went faster. My Moody 31 prefers to be sailed upright - any heeling beyond 10-15 degrees results in the helm loading up and the boat trying to round up., with consequent loss of speed.

To sum up, there's no general rule, every boat is different. You could try the old Dutchman's log - throw a scrap of something biodegradable overboard at the bow and time its passage to the stern. Speed is then a matter of simple arithmetic!

 

[Stemar]

Those narrow boats with long overhangs are designed to be sailed on their ear. The short waterline length when upright got them a better handicap, while the heeled waterline gave them the hull speed of a longer boat.

I think the magic angle depends so much on the boat that it's impossible to say without seeing the design. She sounds like a keelboat, many of which fit the description of narrow with long overhangs, so possible a decent heel will work, but once the keel loses its grip, it's time to level off.

Part of the question is 'Do you need to use a lot of rudder because you are heeled?'
If you can balance the rig while heeled, you can get away with more.

Without instruments, I think this is a good way to start. Also, how high can you point. The less good the keel is doing, the more leeway you'll make, and leeway is never an efficient way to move.

Finally a bit of lateral thinking. Use the GPS on your phone to get a heading and speed while upright, and get her to heel more and more until performance starts to fall off. Just don't fall off yourself - the phone won't like it!

 

[prv]

You could try the old Dutchman's log - throw a scrap of something biodegradable overboard at the bow and time its passage to the stern. Speed is then a matter of simple arithmetic!

Hell of a long feedback loop to figure out what adds or subtracts 0.2 of a knot, though.

It's 2021, just download a speedometer app to your phone.

Pete

 

[johnalison]

Racing is the only sure way of honing one's skills, though instruments can be useful. Most keelboat racers will be happy to sail at any angle of heel if it gains them a few centimetres. This means that they will reef to the lulls whereas a cruiser will reef to the gusts. The point with many cruising boats is that although they may gain a little speed if pushed hard there comes a point where the level of discomfort rises much faster than the speed, though there always comes a point when the increase in weather helm works against you.

My last boat, a Sadler 29 was a bit 'slab-sided', and you could see just by looking at it that it would gain by being reefed early. My current boat, an HR 34, is almost semicircular in cross-section and can be pushed much harder without developing weather helm. You can see that many modern boats with wide sterns are not going to want to heel too much, though their twin rudders will help to mitigate this.

 

[jwilson]

No rule of thumb, all about the boat. Many old long-keelers including my previous boat made best speed heeled 30-40 degrees, my modern boat just won't steer under proper control in any seaway above about 12-15 degrees heel. And the boat is definitely fastest sailed only slightly heeled. In dinghy sailing days almost absolutely upright was usually fastest except for a few "special cases" such as ultra-light winds or a Laser on a dead run by the lee. You could look at a fleet dinghy racing and the ones losing were heeled most.

I've never felt the need for a speed log to get any ordinary boat sailing fast. It only really becomes relevant if you are "sailing to polars" and you have a top-notch pure race boat with a full crew and calibrated instruments.

 

[penfold]

Pretty much any smart phone can have a speed indication via a variety of apps, no need for logs of any kind, or if you don't trust having your portable idiot's lantern on a boat there are very cheap GPS speedometers available. As everyone else has said, it's entirely dependent on hull form what heel angle is optimum.

 

[Caraway]

 

[penfold]

That's not optimum.

 

[Caraway]

Wins though. Certainly lengthens the waterline.

 

[penfold]

Pipers tend to get a bit sinky at that degree of Gourockness.

 

[AntarcticPilot]

That's not optimum.

Inevitable though - no reef points!

 

[penfold]

Heave on the pig and backstay, track down! To be fair whoever is on the main is spilling in the first pic.

 

[Caraway]

Inevitable though - no reef points!

No reefing allowed.