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PostPosted: Sat Jun 13, 2015 5:12 pm 
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Kayaking downstream on a 3 MPH river. Encountered some brush which turned kayak sideways to flow. Kayak flipped instantly. Once I got it uprighted and we were onboard again, it flipped again in open water. It had filled with water and was impossible to keep upright until we got to shore and drained it. Wondering if the flow against the flippers (perpendicular to flow) forced the flip. Also, very surprised with the amount of water the kayak took on,

We were with another mirage tandem and they were flipped twice also.

Rough day on the river. Any similar experiences or explanations?


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PostPosted: Mon Jun 15, 2015 8:30 pm 
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Sure, I'll bite. I'm no expert, but here are some thoughts from my own experiences:

1. Kayaks are especially unstable when they get turned sideways. The first time I took a smaller Mirage out in the Pacific, the swells would turn it sideways, and as soon as it was sideways, it would roll over. The same thing happens when coming in from the ocean. You are doing great, and just about the time you think you are home free, it begins to rotate sideways and over you go. I have also hit submerged twigs and logs, and if hit from the side, over I go. Now, I am exaggerating a bit here. I routinely take both ocean swells and huge boat wakes from the side, but I'm balancing with the waves, something the lower initial stability of the Revo's helps with compared to the Sport/Outback. But if the angle of the water exceeds the secondary stability, you are hosed.

2. When drifting a river in a kayak, you have almost no directional stability, as the water is not actually flowing over the hull or rudder very much. If you are pedaling/paddling with or against the current, then you have directional stability. In my 3-5mph river tests, if I was just drifting down the river it was very easy to get turned sideways, and then you are gonna flip. If I was pedaling/paddling faster than the river, or going upstream, then I had great directional stability. If you notice the drift boats on the river, they are slowly rowing against the flow of the river, just enough to move a bit of water over the hull.

Not sure I helped you any, but those are my experiences.


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PostPosted: Tue Jun 16, 2015 4:20 am 
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Thanks for your reply. I'm not an experienced kayaker and your comments confirm my suspicions.


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PostPosted: Wed Jun 17, 2015 4:45 am 
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i flipped my 2014 several times in March in the gulf (the gulf?!). as was mentioned, if you get it sideways, look out.

I was bringing mine in to beach it, was in about 2' of water with the typical lake waves that you find in the gulf. I pulled the rudder up at last second and the damn motion of that rudder going up almost perfectly swings the boat left 90 degrees. Well that happened exactly as a small gulf wave was rolling in and the yak went over in a split second. broke both rods in the holders.

gotta be really careful, its a very long narrow boat so you have to point into the waves and shift weight sometimes.

all that said, I did about 5 miles on it in the gulf solo, about a mile or so out. as long as I kept it pointing the right way, it was very stable even with no ballast up front and solo.


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PostPosted: Wed Jun 17, 2015 9:23 am 
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Location: Oceanside, California
Use your paddle for stability in rivers and surf... Drive fins up if slipping sideways.

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PostPosted: Wed Jun 17, 2015 9:53 am 
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Location: Out There
Boats are pointy in the front for a reason. Get sideways in moving water and you'll have problems. A cardinal rule of boating is you always try to keep the bow into the wind, or into waves or moving water. If you're in a following swell(waves behind you) or heading downstream, keep the boat moving with the main water direction. A little water may come over the bow, but you won't get swamped. Paddling is a good idea because you can make super quick direction changes which are crucial to control in changing water.

Kayaks float because they displace water, when they get filled up, you can't do much with them. Water is about eight pounds a gallon, add the kayak weight, well, you do the math.

Your Mirage is a larger kayak, it's never going to be a rapids eating river runner. Aim for the calmer water and you'll be fine. You just need to get more experience, spend more time on the water. Be sure you are safe, wear those PFDs if you're doing a lot of unscheduled swimming.

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PostPosted: Wed Jun 17, 2015 10:00 am 
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I was surprised at the ease at which the Mirage flipped. It's marketing message emphasized its stability and how it was all but tip-proof.


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PostPosted: Wed Jun 17, 2015 10:18 am 
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Wildcat31 wrote:
I was surprised at the ease at which the Mirage flipped. It's marketing message emphasized its stability and how it was all but tip-proof.


As kayaks go... These are VERY stable. Don't think we ever suggest them being tip proof though. Depends on conditions, crew weight, crew position in seats and experience. You can lean inappropriately and tip them for sure.

Catching brush seems to be the initial cause of the capsize. Still not clear on how you got so much water in the hull though. Open hatches? Maybe water was in before the tip? That would make it unstable. Leaks?

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PostPosted: Wed Jun 17, 2015 11:56 am 
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I'm very impressed that Hobie reps respond to forum queries. Thanks.
I'll check on leak issue.


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PostPosted: Wed Jun 17, 2015 12:01 pm 
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Noted that this is a 2015... High seat positions are much less stable, so sit in the lowest possible setting. High positions are for site fishing primarily.

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PostPosted: Wed Jun 17, 2015 12:13 pm 
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Yep, that would be an issue. Both me and passenger were in high position.


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PostPosted: Wed Jun 17, 2015 3:10 pm 
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If you read up you will find that a breaking wave has the power to capsize any boat if the wave is big enough, especially if that wave hits the boat side-on (basically no boat or ship is immune to this danger given a big enough breaking wave). The size of side-on wave needed to capsize a kayak is very small indeed - as some of us (me included) have found out when we have succeeded in executing this embarrassing manouvre when arriving back at a beach full of surf bunnies :lol: One key to avoiding capsizing in breaking waves is to stay perpendicular to the waves. This can be difficult if you allow a wave to surf you in because, when a boat is surfing, if you allow the boat to move marginally out of a perfectly perpendicular course, then the rudder does not have the necessary surface area & power to counteract the forces pushing on the much larger area of the hull and forcing it to one side or the other... in which case the sequence will almost inevitably be: surf, slew, flip in rapid succession.

On the couple of occasions that I have managed to avoid the almost-inevitable 'flip' stage I allowed a wave to surf me in, slewed, so the boat was side-on to the waves, and the small collapsed wave then pushed me into shore with the boiling water of the wave right on the side of the boat and the boat almost floating sideways over the flat water in front of the wave (i.e the wave pushing the boat sideways and the boat side-slipping over the flat water which was visibly traveling under the boat as I was making my way to shore sideways on).

Since I never come in to shore in waves of any size without first removing and securing the mirage drive I can be pretty sure that the boat was able to side-slip over the waves because the mirage drive fins were not present to provide additional lateral resistance. Had the drive been in and the fins down I firmly believe that these waves would have flipped me in an instant, not necessarily due to the wave alone, but with the water passing under the boat at the speed of travel in to shore, if the fins had been in and down then the water exerting lateral pressure on the fins underneath the boat, combined with the wave pushing on the side of the boat above the waterline would undoubtedly have flipped me.

Relating this experience to getting side-on to a current in a river: if you are side-on in a current and not traveling at the same speed as the current and you have your mirage drive fins down, then the effect would be more or less the same as my experience - in other words current pushing the fins out from under the boat (to flip you upstream) or pushing the boat downstream over the fins with the fins catching in the water (to flip you downstream). I once saw a similar thing while kayaking down the Ardeche river in France years ago - the river passes through a gorge with near-vertical sides. At a bend in the river where the current had undercut the rock wall and therefore flowed directly into (under) the cliff edge, people whose kayaks hit the wall side-on were instantly flipped upstream. What was happening was that their boats hit against the wall which was then pressing on the side of the boat above the water line while underwater the water was pushing on the other side of the boat in the other direction - result: instant flip of boat.

A similar effect can be felt in non-breaking waves at sea - there is a movement of water within every wave, whether breaking or not, which you can definitely feel and I imagine (though I have never experienced this myself despite having been out in some pretty big seas) it might have enough force to cause a side-on kayak to flip even if the wave was not breaking - and possibly the tendency to flip might be exacerbated by having mirage drive fins extended under the water.

So personally I think that the problems described in this thread are not to do with any particular instability in Hobie's kayaks. Rather the issue is the knowledge that waves (in particular breaking waves) and currents have huge power, and even small waves and relatively gentle currents can exert irresistible forces on a tiny little kayak. The key to avoiding the risks inherent in these powerful forces playing on your boat is to be aware of where they are and how they work and to learn techniques which will enable you to avoid putting your boat into situations where they have a free hand.


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PostPosted: Thu Jun 18, 2015 3:51 am 
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Long time kayakers here....
Keeping a kayak stable and being able to react and adjust your weight and balance quickly is a learned task (lets call it getting your sea legs (similar circumstances). Unfortunately both my wife and I have very high centers of gravity (thats a nice way of saying we are both heavy (lol)). We had an oasis and similar to you when we first started out we would flip pretty much anytime we hit anything unusual. This was not unique to our hobie, we had rented several tandom paddle yaks before buying the Oasis and had the same experience. I suspect having your seats in a high position makes matters much worse (just FYI). It wasn't long at all before we got the balance thing under control (you actually train your body to automatically balance without having to think about it). After a while we took up kayak sailing and have never taken our kayaks out without the sail kit strapped to the side of the boat since (that was like 8yrs ago). One of our favorite pastimes became running mild class 2 rapids with our Oasis initially then eventually with out Tandem Island (in kayak mode with no sails and AMA's), both boats are tandems and very similar. One thing we kind of figured out is in very shallow rivers with a lot of weeds and rocks, or a swift current its best to lock the mirage drives up against the hull (or pull them out (on leashes of course)), raise the rudder and go to paddle mode thru all the shallow areas, weedy areas, and rapids. Obviously if you have raisable seats they have to be in the lowest possible position. The rudder is totally useless if there is not water rushing past it, so it's best to just leave it up and steer with the paddles. With paddles in your hand you quickly learn to use them to help stabilize the boat, basically if you feel your self starting to go over you rotate the paddle in your hand so it acts like a ski (this becomes totally automatic after a while, you dont even have to think about it. Plus with your arms extended when you lean to do your paddle strokes your body weight automatically balances the boat. If you get a chance watch some videos of people in sea kayaks and surfski's in rough conditions. There is a very good reason they use doubled ended paddles. Think about it those boats are up to 24 ft long and only a foot or so wide with a completely round bottom and on many of the surfski's they are sitting on top of the boat (not inside). All stability is done with their body and expert use of their paddles. Of course I'm not suggesting to go out and buy a $6000 dollar surfski (it takes many years of experience just to operate one (these are what they call pro level boats (not recreational)). However all the same techniques they use with their paddles you can apply to your recreational kayak. Now comes the real kicker which gives your hobie a huge leg up over pretty much anything out there. Once you become expert at operating the double ended paddles (a learned skill, and best taught by an instructor, yes there is a technique to learn), you now have the ability to go out in rougher than normal conditions. Your upper body and arms maintain your stability and your feet are just along for the ride doing nothing whatsoever. If the water is deep enough, why not just start pedaling, you don't have to pedal like a madman, just a steady walking pace (both people pedaling at a nice leisure pace) you will find after you have built your body up some you can pedal for up to ten hours and not get fatigued. If it settles down you can always stop paddling and give your arms a break. By the way you discribed your circumstances, my opinion is you shoud have had your double ended paddles in hand and using them for stability and assisting steering, use the rudder if you can but don't count on it, if your drifting with the current it's useless anyway might as well raise it and steer with your paddles (you really need to learn that skill (IMO). Now here come the real kicker that separates your Hobie from everything else on the planet. Chances are your feet are sitting on the pedals anyway and if your smart in shallow water you have one foot forward, and the fins up against the hull. In deeper areas, just start pedaling lightly, your still paddling, but not nearly as hard, with both paddles and pedals for propulsion and paddles in hand for stability you are expending half the energy of any known paddle only kayak.
My advice is learn the paddling skills, when it gets rough you will need them, always have your paddles ready to use if needed (we keep ours strapped to the side of the kayak), obviously with a Hobie you don't need the paddles at all when its flat, calm, and deep enough you just drop the rudder and pedal, giving your arms a break. If you join a paddle group and go out with them a few times, you will learn quickly the right paddling and balance techniques, of course I'm not suggesting at all to leave your mirage drives at home, just having and using them when you can gives you a huge advantage over all the other paddle kayaks out there (after all your feet are just sitting there doing nothing anyway, might as well put them to good use and pedal lightly when you can). Speaking from experience we find our range with our mirage boats is quadruple what it was with paddle yaks expending much less energy.
Trust me here, after a couple months and a few outings, once you have developed some paddling and balance skills you will appreciate owning your Hobie, and will never want anything else.
Hope this helps you
Bob


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PostPosted: Thu Jun 18, 2015 5:14 am 
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Thanks, Bob. Very helpful info.


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