View topic - Drift problems with homemade Kipawa 17'.. Add keel?

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PostPosted: May 9th, 2008, 6:09 am 
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Splake wrote:
[...]
When crossing the wind having both people paddle on the same side can be a really good thing.

What is the good thing then?

littleredcanoe wrote:
[...]
there were times where the most efficient paddling was done by both paddlers on the same side. less corrective strokes to slow us down.

What kind of corrective strokes do you mean?
Assuming a canoe is weathervaning to the left with a wind coming from the left, I (as the stern paddler) would paddle on the left side, as I wouldn't have to do the normal corrections strokes then to go straight. No need then for the bow paddler to paddle on the left side too! If the canoe still would weathervane (too much), I would trim the canoe more stern heavy (bow seat or gear sliding backwards). If that doesn't work, I would slow down. And if that would not work, I would start thinking about buying another kind of canoe, if this was an allround touring/tripping design. (Been there, done that!)
I have tried paddling both on the same side in that kind of situations, but I did not experience any advantage of doing that, and valued my stability more with a canoe that is so severely weathervaning.

Dirk Barends


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PostPosted: May 9th, 2008, 6:23 am 
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littleredcanoe wrote:
One of the fun things about ocean waves is the acceleration you get on the downslope and the slowdown on the upslope..

Except when your bow slows, knifes into the wave ahead while your faster stern coming downwave slues to the side.

Common on ocean waves around here...often several feet high with waves generated by storms elsewhere a thousand miles away.


Don't need an ocean to make waves that do that. Can do it on the good ol' Great Lakes, on most good wind days. The broaching when the bow slows relative to the stern is common on the Kipawa and Winisk with the finer bows and more "deadwood" in the stern.

I will comment on the OP's original question too. Don't add a keel, it won't help your problem at all and it will make the boat less user friendly both for turning and in dealing with beam waves. It wasn't designed for one and putting one on will only have negative effects.

Simply adjust the heading of the canoe to accomodate the sideslip and keep on paddling. The slower the boat is moving forward, the more angle its heading will need relative to your course. Its a simple function of mathematics and vectors, not a mystery of hull design.

Accept its going to take more effort, more time and more work to get there. If its weaker paddlers with you and you can't keep the boat going where it needs to then you're in over your head and shouldn't be there. Plan accordingly and live to canoe another day.

Rounding up is a fairly common trait in well designed boats, as its usually safer and preferable to have a boat that left to its own devices wants to point into the wind rather than point down wind. However the tendency shouldn't be so strong it can't be overcome easily so you can choose your own heading and course.

*Heading: the way the boat points along a line drawn through the bow and stern stems.

*Course: the actual track the boat makes through the water relative to the bottom or shore or other similar fixed reference.

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PostPosted: May 9th, 2008, 7:03 am 
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Hi folks,

I think there is a whole lot of over-analysis going on here. All canoes get pushed around by the wind. Here is the original question, and please have a good “read between the lines”:

Quote:
The problem I had with it last season was the large amount of leeway that it makes in a cross wind. On 1 test run, we were on a lake, maybe 6" waves, say a 5 - 10 km/h wind, & we found that in order to keep the boat from making a substantial amount of leeway we had to keep the speed up very high.
My concern is that this would be just a wonderful boat for camping, and yet my camping partners are rarely strong paddlers. I was thinking of adding a 1/2 or full keel; but don't even know what the standard dimensions are for a wooden keel!


LetsPaddle, the answer is very simple: You and your buddies need to take paddling lessons! :D

Everyone: This is a paddling skills question, not a boat design question! Sheesh, its turning into a boat physics class! :x :lol:

LetsPaddle: When an experienced paddler advises you to take paddling lessons, its not a put down, but rather it’s a pat on your back for you asking a great question, and its encouragement from those of us who have been there, and know the benefit of instruction. You will have winds and waves on every trip - its not the boat, it's you :D But that's OK. Paddling skills, especially those needed in windy conditions and moving water, are not an intuitive skill set. For example learning to lean way way out from the gunwales to reach and pull on aggressive slicing draws while seamlessly linking a powering forward stroke is not an inborn skill. This is a common requirement of the sternsman in all windy and moving water conditions. You will never see beginner or unskilled paddlers using it. Everyone needs paddling lessons from expert instructors. Book a course. Here is the course outline from ORCA to give you an idea of skill set development:
http://www.orca.on.ca/Programs/courseoutlines.001.html

Book a course, have some fun, and in a few hours of instruction followed by practice, your safe water paddling world will open up into vast possibilities and longer trips into wilder places. Go for it!
(If you put a keel on that boat, we will have to kill you 8) )

(OK OK, boat physics is a good thing :wink: )

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PostPosted: May 9th, 2008, 10:04 am 
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Dirk-Barends wrote:
Splake wrote:
[...]
When crossing the wind having both people paddle on the same side can be a really good thing.

What is the good thing then?

littleredcanoe wrote:
[...]
there were times where the most efficient paddling was done by both paddlers on the same side. less corrective strokes to slow us down.

What kind of corrective strokes do you mean?
Assuming a canoe is weathervaning to the left with a wind coming from the left, I (as the stern paddler) would paddle on the left side, as I wouldn't have to do the normal corrections strokes then to go straight. No need then for the bow paddler to paddle on the left side too! If the canoe still would weathervane (too much), I would trim the canoe more stern heavy (bow seat or gear sliding backwards). If that doesn't work, I would slow down. And if that would not work, I would start thinking about buying another kind of canoe, if this was an allround touring/tripping design. (Been there, done that!)
I have tried paddling both on the same side in that kind of situations, but I did not experience any advantage of doing that, and valued my stability more with a canoe that is so severely weathervaning.

Dirk Barends


If you are trying to head upwind and are able to do it without having to fight it and without having to correct then great. That's a light enough wind that you already have the right solution to it. When the wind gets heavier the stern paddler will need to start expending effort in steering strokes to keep the bow headed in the desired upwind angle. At that point having both paddlers working on the same side can reduce the effort that will be lost to steering rather than forward momemtum.

The "good thing" in having both paddlers paddling on the same side is saving energy by taking advantage of that natural steering towards the offside that this setup gives you.

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PostPosted: May 9th, 2008, 10:09 am 
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HOOP_ wrote:
... Here is the course outline from ORCA to give you an idea of skill set development:
http://www.orca.on.ca/Programs/courseoutlines.001.html


Hoop - I am a fan of training and certification but ORCA does NOT have a course to teach Open Water paddling. The Flatwater courses are a good intro which are done in sheltered locations and teach you a number of strokes. The Lakewater program is very inaptly named and is a ballet program which has nothing to do with travelling on a lake but which does give figure skaters something to do when the water is soft. The Canoe Tripping program does not teach paddling but rather teaches trip planning and logistics. Good stuff, but it still won't help with this question.

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PostPosted: May 9th, 2008, 10:33 am 
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Splake wrote:
[...]
If you are trying to head upwind and are able to do it without having to fight it and without having to correct then great. That's a light enough wind that you already have the right solution to it. When the wind gets heavier the stern paddler will need to start expending effort in steering strokes to keep the bow headed in the desired upwind angle. At that point having both paddlers working on the same side can reduce the effort that will be lost to steering rather than forward momemtum.

The "good thing" in having both paddlers paddling on the same side is saving energy by taking advantage of that natural steering towards the offside that this setup gives you.


When having trouble going upwind, I would switch sides frequently to avoid correction/steering strokes and fatigue.
But if we are talking about wind and too high waves to go on in the normal trim, I would paddle kneeled just behind the kneeling thwart or stern thwart. No way I can switch sides frequently then, and neither would I like my bow paddler to paddle on the same side then... No need for too, because what good could that do?

But this topic was about drift, and its side-effects weather- or lee helm.
To compensate for drift, one needs to do that so called cross-wind ferrying.
A canoe that weather-helms a little bit when doing a cross-wind ferry is an advantage in my view, because the stern paddler does not have to do correction strokes then, if paddling on the windward side.
If the canoe weather-helms too much (so that the stern paddler continuously has to do draw strokes to go straight) I have never experienced a real advantage when paddling both on the same side -- I wasn't doing correction strokes anyway, in such a situation. And it hardly -- if at all -- works against severe weatherhelm, because the cause of weatherhelm lies at the stern not at the bow. And if it does work somehow , it only could cause more drift. So if that is worth the trouble?

I only paddle sides when making a shallow turn as fast as possible.

Dirk Barends


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PostPosted: May 13th, 2008, 6:45 am 
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I have been away in Finland for the past 13 days so have not had the chance to respond. But maybe I can help without having to read everyone's comments. Let me know if I miss something important.

First, all boats make leeway in cross winds – ships, sail boats canoes etc. etc. The question is, “How much is too much and how does one reduce it. Some simple math using vectors and such can solve the equation but experience in your boat works well too.

If you feel the boat is making too much leeway (by that I mean you are being blown sideways so fast that your progress towards your destination is compromised) then it is best to adjust the angle of the boat relative to the wind to reduce the leeway effect while maintaining your speed made good to your destination. In other words, you crab your way across the lake.

Imagine first that you are paddling directly across the wind to the opposite side of the lake and steering by compass. In this case you will end up to leeward of your target and will have to turn and paddle up wind to get there. Now imagine that you ignore your leeway and simply paddle towards you target changing your course to suit. You will hit your target and probably have paddled a curved course. Next imagine you paddle using your compass and have estimated your leeway correctly (you might do this in fog or in the dark if you paddle in those conditions). Now you will paddle straight course but with the boat always angled slightly to windward. All three techniques work. From a pure efficiency stand point the second method works best since you will constantly change course to adjust to conditions and maximize performance. This is good because conditions are always variable. The other positive aspect of paddling towards your destination is that you can ignore minor course variation and focus on the “big picture”. Most people steer too much believing that steering a straight course is best when the more efficient technique is to let the boat wander a bit to suit the vagaries of wind and waves. Few people do this instinctively. My son is what I call a “natural paddler”. He always looks like he is on the verge o falling asleep as he pulls slowly away from you. He appears to use the least possible effort to steer the boat and I am not sure he could explain why it is so easy for him.

For what it is worth, paddling at an angle of 30 degrees to the wind is the most efficient angle. There is a lot of very neat math to prove this although one can usually figure it out from experience. Nice to know but not very helpful if that isn't the direction you want.

Adding a keel may reduce leeway (it doesn't always due to the complex flow around the boat) but it will also increase resistance that you will have to live with all the time (up wind, down wind, no wind etc.) and not just when paddling across the wind. So the net effect is negative. You may not notice it but you will pay. Canoes, because they are wide flat boats with significant free board, suffer more than kayaks and other low deep draft boats. Inevitably people will try to compare boats based on experience which, simply put, is waste of time since people are poor judges of what boats are doing because we are not accurate measuring devices and because the input is so complex that we don't really know what is causing what. For example, is the leeway a result of your paddling skill, the boats under water profile coefficient (a coefficient based on the draft, deadrise, and distribution of draft) or the peculiar conditions under which you are paddling.

No doubt some one in this thread will have brought up symmetrically built versus asymmetrically built boats claiming some perceived virtue in one or the other. It is important to note that symmetrically built boats are asymmetrical in the water for all but milliseconds in their lives. The difference is that one is intentionally asymmetrical and the other is accidentally asymmetrical. Both shapes can make good canoes. Many claim that the symmetrical boat has a better balance in wind because the bow and stern are the same height which is untrue unless it is loaded that way. Normally the bow is higher than the stern. Of course, any boat can be loaded to achieve balance in the wind which is why some have sliding seats and packs that you can move around. If a designer knew that you would be paddling all the time on cross winds he could easily design a boat that had minimal leeway. Paddlers stubbornly insist on paddling in all directions and the designer fumble about as best they can hoping to anticipate problems.

Of course, waves play a part. The circular path of water molecules in a wave can cause turning moments that cause the boat to change direction depending on where the bow or stern is in the wave. So long as the waves are non-breaking this is trivial and you should just let th boat wander a bit as the effects are largely self correcting. You will waste effort trying to correct for every little course deviation. If the waves break and the circular molecular motion becomes translational you have a whole new problem. In breaking waves one should not travel across the waves as these cause capsizing moments. In breaking waves it is always best to angle into the waves. Thirty degrees is best. Take your time and let the leeway compensate for your angle to windward of your target (leeway is not always a bad thing). When paddling downwind in breaking waves let your skill and comfort level be your guide. If your love surfing then knock yourself out. If you feel uncomfortable, slow down (back paddle or just drag your paddle depending on conditions) a bit and let the breaking crest pass under you.

So, this was a long winded (and probably inadequate answer) lead up to some advice. Do not worry about the leeway. Trim your boat so it tracks nicely with minimal control strokes, use an efficient control stroke (there is a special place in Hell for the person who invented the “J” stroke), keep your eye on the objective, and enjoy the scenery.

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PostPosted: May 13th, 2008, 8:25 am 
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Imagining to drawing:

Attachment:
File comment: cross-wind ferries
drift.png
drift.png [ 5.61 KiB | Viewed 27 times ]


Jwinters wrote:
I magine first that you are paddling directly across the wind to the opposite side of the lake and steering by compass. In this case you will end up to leeward of your target and will have to turn and paddle up wind to get there.

That would be path number 3 in this drawing I made?

Jwinters wrote:
Now imagine that you ignore your leeway and simply paddle towards you target changing your course to suit. You will hit your target and probably have paddled a curved course.

That would be path number 2 in the drawing?

Jwinters wrote:
Next imagine you paddle using your compass and have estimated your leeway correctly (you might do this in fog or in the dark if you paddle in those conditions). Now you will paddle straight course but with the boat always angled slightly to windward.

That would be path number 1 in the drawing?

Jwinters wrote:
From a pure efficiency stand point the second method works best since you will constantly change course to adjust to conditions and maximize performance.

I wonder why would that be more efficient than path number 1?
I would always try to paddle path number 1, even when in reality it would be probably more like path number 2, because indeed it is difficult to know exactly at which angle to paddle.
And if there was a shore or (rocky) shoal very close on the right side, of course path number 1 would be the efficient choice...

Dirk Barends


Last edited by Dirk-Barends on January 4th, 2018, 11:46 am, edited 4 times in total.

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PostPosted: May 13th, 2008, 8:44 am 
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If its a long distance between start and end points I tend to paddle a path that looks like a mirror of path 2, where I actually make more progress upwind initially than required.

This means that I do the harder part when I'm fresher and less tired and the easier part later when I'm more tired. I always try to do the upwind part first, it often leaves a greater margin for safety.

Of course it demonstrates that there are many reasons for choosing a course.

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PostPosted: May 15th, 2008, 5:48 am 
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Dirk asked about why course #2 is more efficient.

The reason is that the boat is traveling more efficiently throught the water. Because the boat is traveling faster it has greater course stability and you can more easily adjust for varying conditions. For example, you will need to correct your course less. The other nice thinsg is that it is a self correcting course and you need not calculate a proper drift angle which, if your crossing is long, could be wrong

Like all generalizations there may be times when #1 or even #3 are best but #2 works best most of the time due to the high leeway of shallow boats.

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PostPosted: May 15th, 2008, 6:08 am 
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Jwinters wrote:
Dirk asked about why course #2 is more efficient.

The reason is that the boat is traveling more efficiently throught the water. Because the boat is traveling faster it has greater course stability and you can more easily adjust for varying conditions. For example, you will need to correct your course less. The other nice thinsg is that it is a self correcting course and you need not calculate a proper drift angle which, if your crossing is long, could be wrong

Like all generalizations there may be times when #1 or even #3 are best but #2 works best most of the time due to the high leeway of shallow boats.

Interesting and instructive!
Never thought about it that way:
the easiest way is the most efficient course...
Next time I am in this kind of situation on the lake (IJsselmeer)
I will of course try it out... :-)

Dirk Barends


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PostPosted: June 7th, 2008, 12:25 am 
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It sounds like the canoe is fine. When paddling in cross winds you have to try adjusting the trim weight forward or backward until you find a happy medium for the wind, wave and paddling technique. It may be best to have the weight centred a little behind the centre and the stern paddle on the leeward side.

If it was trimmed stern heavy bow light the wind tends to blow the bow to leeward and you have to paddle hard to get across the wind. Generally, move the weight towards the direction of the wind so the canoe self corrects like a weather vane.

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PostPosted: June 7th, 2008, 8:52 pm 
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With path number 1, wouldn't the canoe act like a sail and enlist the wind's help in getting across the lake?


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PostPosted: June 8th, 2008, 2:38 am 
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Ghost wrote:
With path number 1, wouldn't the canoe act like a sail and enlist the wind's help in getting across the lake?

I wonder if the mechanical advantages of sailing are applicable to cross-wind ferrying a canoe. I often have to paddle like path #1 in the small canals where I paddle, because there is no room for path #2. The (hard) work paddling into the wind still has the be done then, in my experience!

Dirk Barends


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PostPosted: June 8th, 2008, 11:31 am 
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A Dirk points out there are probably situations where any path or combination of paths will work fine. For example, if you paddle across a bay and the wind is shielded on the opposite shore you just might want to get in the lee as fast as possible to take advantage of the lighter wind. This might mean paddling a greater distance for the rewards later on.

Of course, if the wind is expected to shift you may want to paddle to meet the wind shift (we always do this when sailing especially in conditions that will promote planing or in light air just to keep the breeze). Sailing experience is often a boon when paddling.

In the end, knowledge of what your boat will do and how it performs when combined with your skills will determine how you approach the problem.

All this is neat stuff. I have seen groups of several canoes paddling in cross winds with the same objective and it is interetsing to see how they finish using different tactics and hearing how the faired. I recall one trip in Labrador where Bill Swift and I took one course and the other canoe took something much different. When it was over the other canoe wanted us to explain why we chose the course we chose because they thought theirs was better. We explained that both of us need to pee desperately and the course had more to do with getting to shore fast rather than getting across the bay.

There may be special reasons for selecting a particular course. :D

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