A kayak stability question

Yes and yes.

Yes, there are a lot of variables, but yes, given the same hull shape and width, making the boat longer will make it more stable. Adding length is just another way of putting more hull in the water, and though the effect on stability in this case is not as pronounced as it would be if simply adding width, the effect will still be quite noticeable.

Probably disagree a bit with Guideboatguy. Overall more hull in the water proportionate to the paddler’s weight should increase stability, but I can name kayaks at 17 feet that would have put you in the water as fast or faster than the Rio did because there are so many factors to a kayak design as well as the paddler interacting with it.

And you are also at the top of the weight range for that boat. It is specifically designed per the manufacturer’s page for the small to medium paddler. In fact their web site shows a female paddling it. You are a medium sized paddler, and well may be sinking the boat to its optimal waterline just sitting in it without gear. A kayak that goes past that waterline gets more unstable, for example that is why you usually get the extra water out of a kayak in an assisted rescue. A waterlogged kayak is too deep in the water hence unstable and extremely likely to capsize again.

But the biggest issue for new paddlers.in a kayak is not understanding that the boat is supposed to be wiggling under them. So you loosen up your hips and let it do so without affecting your center of balance. But if you stiffen up so that your entire torso is going over side to side as well, it is only a matter of time before you will be taking a swim. Especially if you are already at the top of the intended weight for the boat…

The Rio likely does what any other kayak designed for this market should do, which is to be inclined to stop at a certain point before fully capsizing. If you are on the lighter side compared to the boat’s intended paddler, or if you stay relaxed and centered, it will do that. If you are pushing it on size and/or tense so you cannot absorb the motion, it’ll keep going.

The problem for a lot of new paddlers - and many here have gone thru this - is that they choose a first boat based on how “stable” it feels to them when they start. Then they paddle it for a few weeks or a season, get used to the behavior and relax, and find they have the wrong boat. The original challenging boat is slow, boring and not what they want longer term. Hence peoples’ common recommendation to start out buying used and/or take some lessons, to get all of that out of the way without breaking the bank for a new boat that you want to get rid of 8 weeks later.

The Rio is designed for a small to medium paddler.You’re probably on the fringes of what that kayak was designed for. That being said Eddyline boats have hard chines which are less forgiving than a soft chined boat hence a longer learning curve. I think you need a longer boat at least 14-15’.

There will typically be a lot of good info responding to a question from a newbie. Some info may be more thorough than from other people. How do you, as a newbie, even know the quality of the responses? Generally what you see will be good. As an occasional lurker on this forum, I find that Celia gives sound and thorough information. Pay attention to her comments especially.

@shiraz627 said:
That being said Eddyline boats have hard chines which are less forgiving than a soft chined boat hence a longer learning curve.

Adding to Eddyline’s hard chines and flipping - was an issue when I was teaching at a shop that had some Eddylines in their fleet. Got to the point where for beginner classes, I would not use an Eddyline, for I had a decent chance of someone flipping before we got to the rescues section of class (only an issue for intro class - it does seem to be something that is easily overcome by some time in the boat and knowledge).

What I think is that the hard chine that forms the keel seems to be the culprit. If you took the boat out of water and put on a hard, flat surface, you would find that the boat does not want to balance perfectly level on that keel, but instead drop off to one side or the other (a few degrees off balance). The same seem to happens when it sites in the water. if you try to keep the boat perfectly level, you will get all tense as you are constantly working to keep it balanced. But if you let the boat settle a few degrees off of perfectly level, it will find a comfortable position which it balances at easily. If I did have someone using the boat, I would explain how to just let the boat settle to one side, and that seemed to calm people down and make it work.

Other hard chined boats seem to have this issue, but not quite as bad as some Eddylines (for example, many Valleys). In those cases, the issue mostly appears one someone gets all tense, like after they get back in boat after an unintentional flip. Nervous, embarrassed, uncomfortable, etc. Seems they are more likely to end u ind rink again in short order.

Well, my comment regarding additional length when the width and cross-sectional shape are the same doesn’t take into account examples regarding specific longer boats which are known to be even more tender, especially since such examples certainly would NOT have the same width and cross-sectional shape as the shorter boat in question. I do get frustrated with with the shooting-down of examples based strictly on physics which are in the realm of comparing apples to apples just because someone knows of exceptions that involve a comparison of apples and oranges. Being aware of such examples doesn’t make a non-applicable answer more correct than an applicable one. OF COURSE there are longer boats that are a lot less stable than the one named by the OP. I’d be shocked if there weren’t. But that wasn’t what the OP was asking. And I hardly could have made it more clear that differences in hull design will rule the outcome in any case, so no example of a different design being less stable is in disagreement with what I said. Not even remotely so.

Any kayak, surf ski, or even canoe is about as stable as the paddler allows it to be. However, those who carry their weight higher up are going to have to be a bit more conscious of it. With enough time in the boat, it becomes amazingly stable.

1 Like

I agree that @Celia covered the answer very well. I’ll add two things that I can personally relate to.

1) Don’t judge a boat until you’ve spent many hours paddling it in different conditions. A test paddle will give you a sense for the boat’s characteristics, but only a taste overall. Also, if you plan to put a significant amount of weight in the boat for camping excursions, this will also change the boat’s dynamics considerably.

It took me perhaps a year to become comfortable with my Impex Assateague. Likely because I was quite new to paddling kayaks when I purchased it, coming from a canoe-tripping background. Since then, I’ve paddled many kayaks that, in comparison, make my Assateague feel as stable as a fishing kayak (an exaggeration, but makes the point).

2) It can’t be stressed enough that a boat that feels: unstable, twitchy, washy, unreliable, or scary upon first paddle may just end up being your favourite boat after a significant amount of time, experience, and skill building. This assumes you’re in the recommended weight range for a given boat.

Stability is a hard thing to define, and is often debated. Although it may be simple, I do think it’s effective to break things down into a perceived primary and secondary stability to describe what happens when the boat is at rest on flat water and when edging (leaning a boat on it’s side). I have been paddling my Current Designs Sirocco exclusively for the past few weeks since my Assateague has been drying out pending some fiberglass repairs. I have noticed that the primary stability (the ability to remain stationary at rest on flat water) is significantly less than the Assateague. This gives the impression that if you stop trying to actively keep the boat upright, then you’re going to flip right over. However, if you just let your hips loose and keep your upper body centered, you quickly discover that there is indeed a significant amount of secondary stability (though not quite as much as the Assateague). This secondary stability gives the feeling of trying to “push back” against you as you work to edge the boat on it’s side while keeping your upper body centered over the boat. It is important to note that paddler weight, location of that weight, and the weight of other gear will significantly affect the stability dynamics as well.

When I used to paddle the Sirocco only infrequently, I was rather wary of it, thinking it would dump me out at the first opportunity, but I’ve been getting used to it with paddling it more often, and actually starting to like the ability to edge it with minimal effort, and roll it with slightly less effort than the Assateague.

3) Ok, I lied - buy two, get one free. Train yourself to like being in the water. Get yourself a nose plug then practice and perfect your wet exit and a handful of different self and assisted rescue techniques. Falling in by accident is part of learning. Falling in on purpose is key to skills development. You also get the bonus of learning exactly where a boat will transition from trying to right itself to trying to lay on top of you.

Yeah. What Peter CA said. Some boats are stable when they’re leaned a bit off center. Seems like I remember paddling a buddy’s QCC boat that behaved like that. Some folks like that and get used to it. Some don’t.

Wow, thanks very much to folks above! I appreciate the confidence in what I said.

One other factor came up in this thread which I passed on, but given it got raised I might as well speak to it. That is the issue of hard chines. I flip between paddling a boat with a single hard chine and a soft chined boat depending on the paddle and my company. While I cannot say either is more likely to actually capsize, honesty requires I admit that when I first got the single hard chined boat into some decent waves it was felt more unnerving than the rounder hulled boat. And that was after 3 or so years paddling rounder hulled boats. After a while that went away, it has been longer than I remember since I notice the difference between the two.

So yeah, I realized it was very solid on that chine if I stayed out of the boat’s way. But unlike a round chined boat, it really like it is hitting that chine hard. If someone is already uncomfortable with the motion of the kayak, like a new paddler, feeling that whack is only going to make them more tense and likely to stiffen up. Followed by a swim.

The old NDK Romany, IMO, is still one of the most brilliant learning boats ever put on the water. It is extremely kind to a new paddler in terms of staying upright, while having the responsiveness for a good paddler to take into the worst slop that can be found. But take a look at that hull - while it is a single chine, it is a very softened one. The other forgotten design is the multiple chines of the original drop skegged Elaho by Necky. The original release of that boat was pretty disinterested in going straight, but those multiple chines provided a lot of points that the boat would sit on then restabilize somewhat gracefully.

I know there are other, more current boats that carry this kind of ethic, unfortunately I can’t speak well to them because I don’t have seat time there.

Guideboatguy, I found your first post clear, and correct. Celia had a lot of good information, but I don’t think any of it disagreed with you.
As far as answering the original question:
“If that same boat was between 15’-17’, would there be a bit more stability? Or just a longer, faster, twitchy boat?”, Guideboat’s answer is spot on:

“Yes, there are a lot of variables, but yes, given the same hull shape and width, making the boat longer will make it more stable. Adding length is just another way of putting more hull in the water, and though the effect on stability in this case is not as pronounced as it would be if simply adding width, the effect will still be quite noticeable.”

And Celia reiterates it with this:

"you are also at the top of the weight range for that boat. It is specifically designed per the manufacturer’s page for the small to medium paddler. In fact their web site shows a female paddling it. You are a medium sized paddler, and well may be sinking the boat to its optimal waterline just sitting in it without gear. A kayak that goes past that waterline gets more unstable, for example that is why you usually get the extra water out of a kayak in an assisted rescue. A waterlogged kayak is too deep in the water hence unstable and extremely likely to capsize again.

An example for myself would be me, at 190 pounds, finding a 17’ kayak as maneuverable as a 15’ kayak, but a person at 150 pounds finding the 15’ kayak more maneuverable. I need either more length or more width to have my kayak sink the same depth as the 150 pound person. And shallower draft can have an effect on maneuverability. Just one factor, but it is still a factor.

Guideboatguy and Celia both point out that you need more volume somewhere to be more stable. While adding width will make the biggest stability difference, adding length will also add stability, and could provide you with overall better benefits than simply widening for stability.

We can all be stable on an air mattress or an innertube. The world of kayaks tends to blur the difference between sea kayaking, a sea kayaker in a craft that lends itself to effective and skilled sea kayaking; and recreational kayaking, a craft that lends itself to (still very fun) floating about, and keeping unskilled paddlers (still good, wonderful, respectable people, but let’s not call everyone a sea kayaker) feeling stable and upright. There’s no right or wrong answer. It’s what you want to do with it. If you’re ready to declare the Eddyline Rio as a twitchy boat, it’s important to recognize that we’re not presently discussing sea kayaking, nor designs and attributes that any sea kayaker would care to paddle. As Peter mentioned above, he would not use Eddylines for “beginner” classes. And calling the Rio a capable sea kayak (don’t care if you can keep it upright in waves - I’m talking ability to effectively travel in textured seas and wind - whitewater kayaks and waveskis are decidedly not sea kayaks, and waves are not a problem) would be a thin stretch.

It’s hard to imagine, when first starting out, that a skilled sea kayaker has no use for the stability that you hoped for. But it is actually very true, to a surprisingly remarkable extent.

You’ve given an indication that would fly in the face of becoming a skilled sea kayaker. “I got dumped. Rio didn’t like me.”
You either focus on how you capsized the kayak, and how you could improve to make the kayak perform. Or you focus on how the kayak dumped you, and what equipment changes could prevent that from happening again. No right or wrong answer. The answer does help define you as a paddler. 5’8" 165 lbs shouldn’t be a problem in a 12’ x 24" kayak with a capacity of 270

Cape Fear: I agreed with everything ELSE that Celia wrote as well, and over all it was a very good post. But since she said she disagreed with what I wrote, backing that up by saying she knows of examples of boats which were longer but less stable, naturally she must have believed she disagreed with me even if nothing about what she actually said was in conflict with anything I had said. So as long as she seemed to have missed my point, yeah, I tried to clarify what I meant. Anyway, I’m glad you understood what I said back there.

And yes, your post is a good one too, as were a couple others. It is such a common thing for newbies to expect that a stable boat is the answer to all the potential difficulties they might encounter, yet one doesn’t have to be a kayaker to eventually figure out that, paradoxically, an extremely stable boat just makes rough water that much harder to deal with.

I spent many hours in my elite surfski paddling with my feet in the water because it tipped over so easily. And I’ve been an avid kayaker for 40 year with very thin kayaks. My point is, practice, practice, practice. You’ll get it over time.

Thanks for the great responses! I’ve been reading a lot of what goes into a Kayak. Length, width, chines, cockpit size. Etc.

Celia brought up an interesting point about my weight range being at the top range of this particular boat. At first I scratched my head because I thought I fell into the “medium” category at my height and weight. But it now makes sense because my Wife who is same height but 30lbs lighter than me zipped around and pretty much owned it. So I’m guessing she would fall into the small category.

Anyway, That’s why I asked the basic question, if this same boat was another couple of feet longer, would it behave differently.

William

@wrz0170 s,… When I got into it, she was twitchy from the get go…

When you learned to ride a bicycle without training wheels was it wobbly or rock solid the first time?

At 24" beam it was likely you.

@Guideboatguy I apologize for a too-quick response on one point, and agree that is was wrong. I was focused, probably overly, on the chance that as a new paddler the OPer could go out and try a longer boat without confirming its intended paddler. A really big guy would not be able to physically get into a sea kayak that was made for a smaller paddler with maybe subtle seeming diffs from the full size version. A medium sized person could, in fact I know a lot of more experienced sea kayakers who keep such a boat around for its increased playfulness in the right circumstances.

Anyway, point made and maybe the OPer will start looking for a little more boat. Again, did not mean to diss you.

Interesting thread. The Rio is labeled a recreational kayak by Eddyline. It’s hard chined as is the Eddyline Equinox that William (the OP) said he purchased and found very stable in his first thread.

I can’t agree that EDY boats don’t sit flat in the water if the paddler’s weight is balanced in the cockpit. I used a small bubble level on my Samba last summer. It was level horizontally while I was sitting relaxed and centered. While moving forward that changes, as it should if you’re rotating.

I’ve demoed kayaks with rounded chines and prefer the communication of a hard chine. Most likely because that’s what I started and stayed with.

Celia’s mention of size and weight of the paddler made me think of a person’s center of gravity. Am currently paddling a 21" hard chined kayak. A friend who is taller and heavier (he’s very fit and a much better paddler) has the same kayak and finds it twitchy in waves and chop. I think it’s the most stable and secure kayak I’ve ever paddled in 2.5’ foot waves and confused water and attribute our differences to my lower center of gravity.

Rookie, it is also volume. One thing that the canoe folks do very well and gets disregarded when it comes to kayaks is how much weight is required to sink the canoe to its optimal waterline. Sink it too little it bobs around and you are not going to get the most out of the control surfaces on the hull, but it won’t be unstable in the way we think about it with kayaks. Sink it too much and it starts getting unstable. It works the same for kayaks, but you don’t see the clear numbers telling you where that waterline is with kayaks compared to canoes. It is more easily discovered by the kayak’s behavior and, in some boats, whether the bow and/or stern are properly engaged with the water.

That is where weight comes in - though someone sticking higher out of the cockpit does have more work to do to maintain their center of gravity. You are likely a bit below its highest design weight so are unlikely to go past that magic point. Your friend may be right at it so any boat movement puts him deep enough to start altering the stability.

I can’t comment about the specific boat, since I’ve not paddled one.

Fit could be a problem, as well. If the paddler is not in good contact with the boat, it will not feel stable.

Length affects stability some. Since the boat, when it leans, is spinning around an axis point somewhere above the waterline that varies with the total center-of-gravity of the boat+paddler. Beam, and as this is a medium to wide 24 inch beam, certainly affects the feeling of stability more. I expect that the length was less an issue for this paddler that some other factor in the boat/paddler configuration. Length does (often) add to the LAW (length at waterline) and this may affect the center of gravity (a wide boat will tend to gain less LAW than a skinny one and the paddler might need to have this hull deeper in the water to feel comfortable). Adding weight to the boat can increase LAW and it is possible that the trim/fit for this paddler was altered enough that the boat became (or felt) unstable. It may, or may not, have changed the stability characteristics of the boat, but there is no way to know this without testing the hull.

It is possibly true that the paddler’s center of gravity was wrong for the boat. Lowering the seat might have a major impact on this, but that can cause problems with paddling if one has to sit too deeply in the boat.

Guillemot kayaks has a decent treatise on stability and it is worth looking at the following link:

http://tinyurl.com/yckstbfc

Rick

And to add, we wear a sea kayak, we don’t sit in one. If you are lose inside it will feel unstable. If locking yourself in is uncomfortable them pad the inside of the deck so your knee area is lightly pressed inside. Make sure your foot pegs are in the correct position to create a snug fit.