planing

Moderator: GreenLake

Can you plane your Daysailer?

You are able to achieve a plane in your DS under the right condions.
33
89%
You are unable to achieve a plane in your DS under the right conditions.
4
11%
 
Total votes : 37

Postby Peter McMinn » Fri Feb 03, 2006 1:13 pm

Sure sounds like a plane to me. It's that lifting feeling that is so marvelous.

Curious as to the position of your centerboard if you had much vang in.
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Postby michaelyogi » Sat Feb 04, 2006 12:32 am

I don't have a vang (yet) and the centerboard was all the way down. What was really impressive to me was the wake.
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just a comment

Postby Roger » Sat Feb 04, 2006 10:04 am

With a reefed main and storm jib, you were likely facilitating planing even more as this configuration allows the boat to sail more upright with less heeling. This presents more of a flat aft surface of the hull to the water which facilitates plaining.

The only two other piece of advice I would have, would be to both move slightly back when you are approacing planing speed the get the bow up and starting to climb its own bow wave. Once you get up on the bow wave and start planing, move slightly forward so that the transom is not dragging in the water. The the first tactic will get you up onto a plane sooner, and the latter tactic will keep you on a plane longer.
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Postby Gonzalo Paz » Sat Feb 04, 2006 8:53 pm

when sailing downwind, you let the mail touch the spreaders? Last weekend I made a fairly huge hole in the main, because it layed against the spreaders for a while, even though I used the vang . ¿Do other sails have a reinforcement there?

(PD: I sail in Rio de la Plata, Argentina, in a DS I bought last NOvember)
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Postby dsheer » Mon Aug 28, 2006 4:40 pm

Gonzalo,

Rubber caps on the spreaders keep rips from happening. They're shaped like T's, and cost too much, but they're worth it.

I also vote that the boat planes. It did so the first time I took it out, and does so every time I'm near a beam reach in more than about 12 knots of wind. Sometimes I have to float (luff) the main to keep the boat upright, but she still planes. There's a small rooster tail behind the rudder, and the bow wave crests way behind the boat. Not to mention that you're blowing by the 35 footers on the same course, and watching their crews scurry to figure out how a little boat can fly by them. Did that this weekend. Sweet.

I don't think I've planed the DS1 on a run. My old Shark would do that with the spinaker up in 18 knots or so. In those conditions you 'bout need to sit on the transom anyway to keep the bow up.

One thing sure, though, I can't keep up with a J22 to windward in that kind of breeze.

Dan
dsheer
 
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Re: planing

Postby Interim » Tue Jul 05, 2016 10:12 am

Has anyone planed under mainsail alone?

I was on our local lake last week in 13-14mph winds, main only, on a beam reach and sailing very flat. The bow wave seemed to be starting a foot or so forward of the mast, and we were cooking right along.

But I didn't think I'd be able to plane without the jib.

Any experiences or thoughts that would shed light on this?

Thanks.

--john
1979 DSII
Interim
 
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Re: planing

Postby Lil Maggie » Sat Jul 09, 2016 8:58 pm

I have, under reefed mainsail...hit eight knots sailing a bowline with myself and the wife hiked out and howling in the wind like mad monkeys. Winds that day were 20-30 with gusts up to 35-40...almost went over a couple of times
Mike
A crappy day sailing is better than a good one at home...
DS 1 #2313
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Re: planing

Postby Interim » Mon Jul 11, 2016 1:46 pm

wow. You are hardier that I am.

--john
1979 DSII
Interim
 
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Re: planing

Postby GreenLake » Mon Feb 06, 2017 11:36 pm

Well, I thought I'd finally managed to get the DS on a plane, but perhaps not so.

We had a mid-winter race when a front came through,the wind whipped up, with gusts up to 27 knots (30+mph), enough to kick up waves higher than a foot on our lake (fetch about a mile). We were going wing on wing downwind, very nicely surfing down the waves, and the GPS read 8.5. When reviewing the track, which shows speeds averaged over 200+ foot segments, the highest speed was still 7.9 knots.

Was it planing? If you use the standard formula of 1.34 the square root of the waterline length, you get 5.3 knots for the hull speed. This formula simply accounts for the wave length of the wave train (bow wave) at any speed, with the "hull speed" taken to be the wave length at which the trough is at the stern and the boat is continuously "climbing" the bow wave.

Turns out there's a variation to that formula due to David Gerr, which replaces the geometrical constant 1.34 by something depending on the displacement to length ratio. The idea being that lighter hulls can go faster without necessarily planing.

The physics behind that formula might be that a lighter hull can move partially up the bow wave, that is, have the stern forward of the deepest part of the trough of the bow wave.

Assuming 1120lbs for a fully crewed DaySailer, and using that formula, you get a factor of 1.85 instead of 1.34, and the top 'hull" speed would increase to 7.4 kt.

This is pretty close to the maximum we observed, so did we reach a plane? Perhaps for a moment when we saw the momentary speed go to 8.5, but most of the time it didn't look like the bow was really lifting out of the water. (We were distracted a bit, a friend sailing a laser ahead of us had just capsized in our path, so we weren't focused on doing things like getting our weight aft).

Anyway, it was significantly faster than the usual (barely over 6 knots) that we seem to reach quite easily. Because in most conditions we top out at 6.1, 6.2, perhaps briefly 6.3 knots, I had assumed that those speeds represent the effective hull speed for the DS. But looking at Gerr's formula, it would appear the value is actually higher, and true planing comes even later.
~ green ~ lake ~ ~
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Re: planing

Postby K.C. Walker » Mon Feb 20, 2017 5:26 pm

Green Lake,

That makes sense to me that the planing factor would be over 7 kn. I hit that speed often enough when using the UPS. I can also tell that the boat isn't fully broken loose onto a plane. The boat is a little too heavy to respond to pumping and ooching, especially when I'm solo. If it's choppy out and with standard sails, it works much better going crossways to the waves on a beam reach, and that can be quite thrilling. Though, my most exciting planing happens with the UPS on a broad reach. This gives me the safety valve of being able to head down if things get too crazy! The problem with that is that I tend to do that first and the slog home is usually wet and brutal (and takes waaaay longer).

Sometimes I contemplate extending my side decks with some kind of bolt on wing. I'm too chicken to use a trapeze. However, I would like to be able to hike out further as there are times that I know I could get planing if I could just get the boat flat.

I am jealous that you're getting out sailing! There is still plenty of ice here.
KC Walker, DS 1 #7002
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Re: planing

Postby GreenLake » Mon Feb 20, 2017 7:11 pm

Winter and spring tend to be better for higher wind scenarios here. So, we just had another day and I was able to hit 8kt on a reach and 7kt going downwind --- with a reef in the main and two crew.

The downwind portion did feel like we were getting close to planing, but we didn't have any nice waves to surf. That might have helped. Three weeks ago was a different story. We did notice, and one of the crew commented on that the DS seems to "throw a lot of water" when going above 6 knots. Comparison would be to a boat like the 5o5.

I don't have hiking straps; if I were to sail more often in these conditions, I think I'd definitely want some - as it is, the need would be limited to a handful of days every other year.

As a result, we didn't really sail the boat flat, except downwind.

I did finally get around to completing my vang. Only 12:1, but seems to work OK and it held up to the conditions. Helps keep the reefed sail in better shape as well. (I had been concerned because I don't have a good/standard place to attach it to the mast, but what I did, seems to work).

We did put in a reef this time, as the forecast was for winds building during and after our race. Instead, we had a brief peak around the start and first half of the race, then we got some rain during the second half, and, true to form, the wind went away with the rain. We shook out the reef and then the wind came back a bit, just about to the point where the press on the sails was as big as on the reefed sail before.

Fun day, but water was so cold that we sailed a bit on the conservative side: capsizing wasn't in the plan.
~ green ~ lake ~ ~
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Re: planing

Postby K.C. Walker » Mon Feb 20, 2017 9:01 pm

I really can't imagine trying to get the boat to plane without hiking straps, to me they are essential. It makes it so much easier to handle the boat in higher wind conditions. Maybe it's not easy but it's not that difficult or scary… And worth it even for a couple of times a year! :-) Also, having a good vang to keep the sail under control is a huge part of high wind sailing and greatly helps the boat in planing. Both of these help so much with gust responsiveness. Instead of just spilling that power you get to deliver it to the hull.
KC Walker, DS 1 #7002
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