Eddy lines, boils and rips

[spider]

My friend will be visiting from Quebec for a couple of days practice for an upcoming trip.

My question is mostly about "boils" (ewww not the skin kind) and touring kayaks.

I occasionally have to deal with them. (though nothing that big or huge as yet) I am wondering what is the primary consideration when paddling them.

Eddy lines, I know you can trip over, is it much the same with boils?

I know your paddle has a different bite when passing through them. Is it safe to assume that they are also physically higher than the surrounding water and can trip you in much the same way ?

thanks

[PeterB]

My friend will be visiting from Quebec for a couple of days practice for an upcoming trip.

My question is mostly about "boils" (ewww not the skin kind) and touring kayaks.

I occasionally have to deal with them. (though nothing that big or huge as yet) I am wondering what is the primary consideration when paddling them.

Eddy lines, I know you can trip over, is it much the same with boils?

I know your paddle has a different bite when passing through them. Is it safe to assume that they are also physically higher than the surrounding water and can trip you in much the same way ?

thanks

a boil, as I understand it, is an upwelling of water; In my experience not that hard to paddle over , but where theres a boil there're usually other currents ; its often an indication of a messy confused area , water flowing every which way.

Sometimes one paddles through areas of moving water that are confusing and defy description or explanation; water flowing and swirling every which way, including upward. The Portsmouth area and mouth of the Piscataqua is one such area, discussed recently on this message board . its hard to invoke any specific technique other than to stay relaxed,

keep the hips loose to allow that lovely kayak hull to do what does best. With loose hips and a loose hull you can hopefully edge the right way at the right time, away from the current, which in these kinds of areas ,can change frequently, or at least not keep the hull from responding as it will to the water around it. Conversely, tensing up and keeping legs tightly braced against the boat stiffens the hull and makes it harder to edge; a bad thing.

Also, ;whether its in surf or in current, a moving boat is always good, so keep paddling.

[NateHanson]

Boils are tough. They'll trip you just like an eddy line, but unlike an eddy line they don't stand still. That means you can't easily lean one way or the other to prepare for them, as you can with a sharp eddy line. The best defense, in my experience is to keep paddling through that area, and get across quickly. Don't dally where boils lurk, unless you're there for the challenge. In the latter case, keep ready with loose hips and a quick low brace. When they get big and grabby, they'll take you down on one side, and then just as you do a deep brace, it'll put you on your ear the other way! Good place to practice rolling too, if you're looking for a challenge.

You'll find boils at the downstream end of a strong eddy line, where it's becoming less distinct and wider. Good reason to cross eddy lines at their upstream end, and do it quickly.

[EEL]

Is it safe to assume that they are also physically higher than the surrounding water and can trip you in much the same way ?

Think the "how do you deal with them" has been well covered. In theory a boil is higher than the surrounding water. The current radiates from the center, sort of, as it moves to a circular boundary edge. So when you enter a boil, the odds are the bow is going to get shoved one way or the other, then it will encounter the boundary which is eddyline like, sort of, while the rest of the boat is getting shoved by the radiating current. All of which can make for one of "those" moments.

So maybe that helps think about how to deal with them, but more likely it is something to add to the mix when wondering what just happened to me and my boat.

If boils are near places you do not want to be, make sure you enter it in a way so the current shoves you away and not into the nasty place.

Ed Lawson

[pikabike]

Think the "how do you deal with them" has been well covered. In theory a boil is higher than the surrounding water. The current radiates from the center, sort of, as it moves to a circular boundary edge. So when you enter a boil, the odds are the bow is going to get shoved one way or the other, then it will encounter the boundary which is eddyline like, sort of, while the rest of the boat is getting shoved by the radiating current. All of which can make for one of "those" moments.

So maybe that helps think about how to deal with them, but more likely it is something to add to the mix when wondering what just happened to me and my boat.

If boils are near places you do not want to be, make sure you enter it in a way so the current shoves you away and not into the nasty place.

Ed Lawson

Thanks for the above description. Don't think I've ever read a definition of a boil, though I got a hint of it from the generic term, as in "boiling water."

Whatever it is, just don't be sitting there and staring in fascination at one like I did, despite knowing that was likely to end up with me up-ended. The surprising part was how *quickly* it flipped me over. That was my first combat roll on the so-called off side in a river. And yeah, it was good training.

[B]

My friend will be visiting from Quebec for a couple of days practice for an upcoming trip.

My question is mostly about "boils" (ewww not the skin kind) and touring kayaks.

I occasionally have to deal with them. (though nothing that big or huge as yet) I am wondering what is the primary consideration when paddling them.

Eddy lines, I know you can trip over, is it much the same with boils?

I know your paddle has a different bite when passing through them. Is it safe to assume that they are also physically higher than the surrounding water and can trip you in much the same way ?

thanks

Here in Puget Sound the tidal flows create some pretty strong currents creating boils either as a product of whirlpools or water being forced to the surface by flowing over a drastic decrease in depths.

Whirlpools , created in our case by two opposing directions (current and back eddy) of moving water, creates a vortex sucking the water towards the bottom. The water that was pulled down by the vortex is then released at the bottom of the vortex to create a boil as the released water reaches the surface. In less restricted areas, the flowing currents simply flow over sharp increases in the bottoms contour pushing the water to the surface near that point. We literally have small mountains under the surface here in Puget Sound specifically around the San Juan Islands where I teach expeditioning classes with an emphasis on currents.

Bob Burnett

[scamlin]

On a good day you can find a boil or two along the eddy line down some from the light at The Race. If I encounter one coming back in off a down current run, I'll try to avoid it. If I inadvertently run onto one drifting with the current or wind pushed, it's when I've got a camera pressed up to my face waiting for a decent shot to come along. As in the thumbnail, it will ruin your shot everytime. Boil is in the foreground of the first shot. Depicted in the thumbnail is Greg Paquin back in November of 2002. Pics 2 and 3 are thrown in just for fun. Dave Fasulo was the third paddler that day. Yes, we were lucky no one swam that day. I should note, I rarely play the ebb at The Race anymore and no longer encourage anyone to do so.

Carl

Carl:

Thanks for the pics. Just curious, though, why you no longer play the ebb at the Race?

Scott

[Doug]

Try this out for size. If this whirlpool doesn't get your heart thumpin, your already dead.

[rick stoehrer]

Carl:

Thanks for the pics. Just curious, though, why you no longer play the ebb at the Race?

Scott

not speaking for carl but the ebb at the race can be dangerous. there are a lot of things that can go wrong there on a "nice" day and if your group isn't dialed in pretty tight, those things that go wrong can quickly escalate...not the least of which is that on the ebb, you are being washed out towards the shipping channel and block island sound if you end up out of your boat, can't surf it or get into the eddy behind race rock.

even if nothing goes wrong....5 miles out...play hard....5 miles back. that's a long day for most.

on the flood you can play either at the western (race) end of fishers (still a long day but if someone ends up outta the boat, you're getting washed in...still not good but it ain't out to sea) or the eastern end. the east end launch is a whole lot closer too so it makes for a shorter day.

personally i think fishers is a place that you should only paddle with a very, very competent group, in a class with a very competent set of instructors and in either case, you need to have someone along with some local knowledge.

first time i went down there was in a group prepping for our 5* and with the exception of the local (greg paquin), we were all very surprised to see the ocean do some of the things it did. it is like nothing else i've seen on this coast.

[tyson]

personally i think fishers is a place that you should only paddle with a very, very competent group, ...

Then WTF were you doing out there last year with a couple of newbies in a racing tandem?!

...turned out to be mild conditions that day.

[rick stoehrer]

Then WTF were you doing out there last year with a couple of newbies in a racing tandem?!

...turned out to be mild conditions that day.

it's funny...i thought you guys knew greg and greg thought you knew me!

in any event having very competent people around you can cure a host of ills. who was it? me, greg and paula anyways...even had you totally boofed it, there wasn't anything going on that we couldn't have sorted out in short order and we were on the east end on a flood...which is more conservative. i think you understand this but we watched you like hawks on a chicken! you 2 woulda been back in that boat before you knew what the hell was going on had anything happened! but it was fine and fun and we all came back with a giggle.

have you been there on the ebb? it's quite a different experience.

[tyson]

it's funny...i thought you guys knew greg and greg thought you knew me!

Well, we had met everyone at least once before...

but it was fine and fun and we all came back with a giggle.

It was, we did. ...and I've figured out the fit/ergonomics problem with me and the boat that resulted in a broken back band that day.

have you been there on the ebb? it's quite a different experience.

It was early ebb on the reef when my back band broke. ...but regardless, it wasn't looking like top notch conditions that day. Its on our list to get out there again when things are hopping a bit more. Someday I'd like to see The Race, but as you've said, its a good bit of paddling just to get there.

[rick stoehrer]

Well, we had met everyone at least once before...

It was, we did. ...and I've figured out the fit/ergonomics problem with me and the boat that resulted in a broken back band that day.

It was early ebb on the reef when my back band broke. ...but regardless, it wasn't looking like top notch conditions that day. Its on our list to get out there again when things are hopping a bit more. Someday I'd like to see The Race, but as you've said, its a good bit of paddling just to get there.

that sounds about right...we got the end of the flood at wiccopesset and then hung around to see how early in the ebb we might be able to use the east end....it was a beautiful, albeit flat day.

[spider]

Sounds like a plenty wild place.

I'm curious about the tandem, rudder etc. Wondering rudder up or down?

(I think I asked much about skegs a year or so ago)

Reason I'm asking this time is that there have been times when the force of the water on one of our boats (the tandem) has been stronger or almost stronger than my legs. That boat in particular has the largest

rudder of any boat I've padded. Occasionally I think of reducing the size of it but really don't know if that would just be a lesson in futility.

(Pretty sure it's safe to ask a rudder tandem question without people jumping in saying real paddlers don't use rudders, etc. etc or at least I hope so.)

[Doug]

Sounds like a plenty wild place.

I'm curious about the tandem, rudder etc. Wondering rudder up or down?

(I think I asked much about skegs a year or so ago)

Reason I'm asking this time is that there have been times when the force of the water on one of our boats (the tandem) has been stronger or almost stronger than my legs. That boat in particular has the largest

rudder of any boat I've padded. Occasionally I think of reducing the size of it but really don't know if that would just be a lesson in futility.

(Pretty sure it's safe to ask a rudder tandem question without people jumping in saying real paddlers don't use rudders, etc. etc or at least I hope so.)

No worry Spider.... Most hull designs need the use of a rudder where others do not. There are a boatload of variables that dictate their being deployed. As far as deploying your rudder in the circumstances mentioned above, it depends upon what you are trying to accomplish. To that I leave an explanation to those more scientifically concise. I will say that there is the option of partial deployment if you are concerned with the overall size of your rudder. When crossing eddy lines and in confused waters, beware of deployment as in these situations your goal may be to allow water to flow uninterrupted under your hull rather than offering skeg or rudder resistance unto the picture.

[tyson]

Sounds like a plenty wild place.

I'm curious about the tandem, rudder etc. Wondering rudder up or down?

(I think I asked much about skegs a year or so ago)

Reason I'm asking this time is that there have been times when the force of the water on one of our boats (the tandem) has been stronger or almost stronger than my legs. That boat in particular has the largest

rudder of any boat I've padded. Occasionally I think of reducing the size of it but really don't know if that would just be a lesson in futility.

Our tandem has no keel (round hull) and lots of rocker below the water line. ...or very little hull in the water out at the ends. Its tracking is horrible. This is typical with racing hulls and why racing hulls typically have rudders. The boat is manageable with the rudder up, but a lot of effort goes into steering instead of paddling. This is particularly frustrating when trying to stay in sync with my partner.

Though our boat is light, with two people in it,spaced apart as we are, the inertia around the yaw axis is considerable. That combined with the boats mild tendency to veer off course (instead of track) makes paddling it with the rudder up quite frustrating.

When trying to maneuver in place or when I'm concerned about damaging the rudder, I raise it. Otherwise, its normally down. This is true even when surfing. Using the rudder lets me steer the boat while putting in good strong forward strokes to catch the wave.

I've long been tempted to try taping on a little bit of keel at the back of the boat to improve its tracking and see if I can go without the rudder. I hate rudders. I hate rudder pedals taking up space in the cockpit. I hate the rudder and its control horns catching on things. I hate worrying about breaking the rudder. I hate pulling it up. I hate putting it down. ...but I've not yet done that experiment and in spite of the rudder, I enjoy our fast tandem and so use it anyway.

I've never had trouble with the forces on the rudder pedals so long as the rudder is all the way down. It may be worth noting that our rudder doesn't sweep or extend back. It is a tall, narrow vertical SmartTrack (sp?) blade.

Doug, I've played with putting the rudder part way down. The result is VERY heavy rudder forces. When the rudder is fully down, the moment arm is very short. When the rudder is pulled up a little, it moment arm gets much longer. Additionally, on a long boat, it doesn't take much swell/wave to cause the rudder to no longer be in the water at all. IMHO, put it all the way down, or raise it completely.

[emilie]

More on the tandem: There is a whole lot of maneuverability at the front of the boat too. We got much better at surfing once I really focused on managing the bow and placing it where it needed to be. I have found a bow rudder quite effective in rough water.

[leong]

Our tandem has no keel (round hull) and lots of rocker below the water line. ...or very little hull in the water out at the ends. Its tracking is horrible. This is typical with racing hulls and why racing hulls typically have rudders. The boat is manageable with the rudder up, but a lot of effort goes into steering instead of paddling. This is particularly frustrating when trying to stay in sync with my partner.

Hmm. From the pictures of the Bullitt K-2 racing kayak (see http://www.westsideboatshop.com/html/Kayaks/HiPoTouring/Bullitt.htm) it sure looks like this tandem has very little rocker compared to a traditional sea kayak. Also, since the water-line length (23 ft.) is only 6-inches less than the overall length (22.5 ft.), it looks like most of the hull out at the ends is in the water. Anyway, racing boats have rudders mainly because rudders are more efficient than using corrective strokes to hold a course or change direction. But you’re probably right that the rounded hull reduces straight tracking. However, I think the long water-line lengths of typical racing sea kayaks (or surf skis) make them track pretty well (at least on flat water), but at the cost of being hard to turn.

[tyson]

Hmm. From the pictures of the Bullitt K-2 racing kayak (see http://www.westsideboatshop.com/html/Kayaks/HiPoTouring/Bullitt.htm) it sure looks like this tandem has very little rocker compared to a traditional sea kayak. Also, since the water-line length (23 ft.) is only 6-inches less than the overall length (22.5 ft.), it looks like most of the hull out at the ends is in the water.

I am referring to the shape of the hull below the waterline only. Some boats have a keel that is very flat for most of their length and then bend up more sharply upward at the ends. Others have a keel line that curves upward more progressively starting near the middle of the boat. These have less draft near the ends. The advantage of this is to reduce wetted surface area. Having the keel go deep (relatively) into the water where there is little beam, results in wetted surface area, but no much buoyancy.

If you look very carefully at a modern performance hull, you'll see that though the water line goes all the way to the ends, there is very little draft near the ends compared with many recreational boats and some conventional sea kayaks. ...even if the rec/conventional boat has a bunch of hull that hangs out over the front above the water line.

If I've failed to paint a useful picture, I'll try to come up with some graphics.

Cheers!

Ty

[Pintail]

Tyson, if your boat is like the boat in the pictures at the link, then I cannot see any rocker to speak about -- not what I call rocker, that is. Now go out and look at a Pintail and <that's> "rocker" (or my trusty, old Skerray RM). I also think that Leon knows what he's talking about in a conversation about racing, so tread carefully...

Emilie, the inherent problem with using bow rudders is that it also causes <tons> of drag. The bow rudder is superb when turning dramatically or fast (as you know), but if you use it when racing, you are going to be <losing> ground because it knocks speed off (oh, and potentially threatening your shoulder if you are aggressive, due to your racing speed) -- in that instance, surely stern ruddering (or external rudder at the stern) is more efficient (which is what Leon was suggesting, all along)?

I am not trying to start an argument here, please note! ;^)

[tyson]

I also think that Leon knows what he's talking about in a conversation about racing, so tread carefully...

That's why I'll not continue that thread unless I find time to prepare better material. There are multiple aspects to rocker and you guys are missing one of them.

Emilie, the inherent problem with using bow rudders is that it also causes <tons> of drag.

I dare you to say that to John Carmody. ...and I hear he knows a thing or two about kayaking.

I am not trying to start an argument here, please note! ;^)

Why not? Having an off day?

Cheers!

Ty

[lhunt]

Emilie, the inherent problem with using bow rudders is that it also causes <tons> of drag. The bow rudder is superb when turning dramatically or fast (as you know), but if you use it when racing, you are going to be <losing> ground because it knocks speed off...

I think Emilie was talking about being the person in the front seat of a tandem while surfing, which is, like, Wow, as far as I'm concerned. The dynamics in that situation are certainly different than racing in a single. So this is not a rebuttal to that, at all.

However, when you start racing, the question is how to deal with the turn buoy. I experimented with a bow rudder and my mechanical rudder and just lean 'n sweep. I knew that the bow rudder would reduce forward momentum, but I reasoned that the tradeoff might be worth it if you're going in the wrong direction in the first place. It turns out that having to re-accelerate to speed afterward is too expensive.

The other day I was racing without a rudder slightly behind a gentleman in a sea kayak when the buoy happened. He went in close to the buoy and used a bow rudder, swinging out wider after the turn. I went in wide and leaned hard to sweep on the outside, crossing through his wake and coming back in closer to the buoy. I passed him easily on the inside while he worked to get back up to speed, though we seemed to be pretty well matched otherwise. OK, there were a lot of other variables there, but it seemed to be a convincing real-world confirmation.

Of course this is only one kind of turn - different strokes for different, ah, situations.

-Lisa

[Phil Allen]

.... I understand that the bow rudder takes away all your forward momentum very quickly, but I reasoned that it shouldn't matter much if you're going in the wrong direction in the first place. But it does. Having to re-accelerate to speed after the bow rudder is too expensive.....

.....

But of course this is only one application - different strokes for different, ah, situations.

-Lisa

Lisa- a well executed bow rudder should not take away speed. Just like with the rudder (boat or paddle) at the stern, it only works when water is flowing smoothly over the blade. Many paddlers just stick it out there like a pole in the water to pivot around, which will rapidly kill all speed.

I thought Shawna and Leon had a good video but can't find it. Instead there's a good example of a former club member doing one

: It's not ideal as he turns to the opposite side of the camera, but you can see a) the momentum changes slowly and b ) there's no big pileup of water on the blade. In contrast, Ken Whiting shows the bow rudder as pivot stop

.

Phil

[EEL]

It turns out that having to re-accelerate to speed afterward is too expensive.

I don't think it matters what you are racing, exit speed onto a long straight is critical. I suspect it was the different arcs around the buoy as opposed to the turning strokes, as such, that made the difference since it allowed you to carry more speed. That said, I have no doubt he stalled the boat via a sharp pivot doing a bow rudder. The interesting question is how effective would a bow rudder have been compared to other techniques to create the arc you used. I suspect not as effective since it would inherently mean your paddle was not being used to keep speed up while stuck in the water as a rudder.

Don't know how badly a bow rudder bleeds speed in the abstract compared to other techniques, but I suspect how it is done has a huge influence as well as just how quickly you are trying to pivot the bow. My shoulder tells me opening the blade very much to "drive" the bow around fast creates large stalling forces. In a gentle turn that is almost a cross brace turn, much less so as the video shows. I have often often seen people using it as a combo stroke to turn and brake to make a sharp turn which leads to the thinking the stroke inherently bleeds much speed. As in almost stall the boat to get lined up and then forward stroke onto new course as opposed to turning onto new course.

Seems like this discussion raises good subjects for experimentation at a lake skill sessions.

Ed Lawson

[Doug]

I find that the beauty of the bow rudder is that when you complete your turn, you can continue your forward stroke with little wasted time or effort on the same side you origionally deployed the rudder. Kick up the your power level and your up to speed in 3 or 4 strokes.