Tidal Rapids Experiences?

Discussion in 'General Paddling Discussions' started by puddlejumper, May 29, 2017.

  1. puddlejumper

    puddlejumper New Member

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    Over the last few years I've started to venture into some areas with strong rapids (Ripple Pt, Green, surge narrows, okisollo, Race Rocks, Trial Island, etc...). I've been trying to read up on these areas but there seems to be relatively little information about them. For the bigger rapids (okisollo), I've used current tables to avoid them at maximum flow, but some others I've run during high flow. For the most part the rapids seem pretty fun and harmless, but there were a few experiences with some weird features that left me feeling a little unsure of what to make of them.

    There was one particular experience, just off the North end of East Thurlow, where we ran some heavily flowing rapids which were unlike anything I'd experienced in the ocean before. Some of the scariest parts we encountered in that section were these absolutely massive whirlpools and also these features which seemed to form along the edge of boils that were like eddy lines on steroids. They were like a rip between the edge of the boil and opposing currents. One of these things had a suctioning effect that grabbed us and sucked our kayak down to the point it was almost entirely below the waterline (to be fair our kayak was already sitting quite low from the weight of us and our gear). It held us there and just kept washing water over us. We had to paddle pretty fiercely to get out of that effect, though I imagine eventually it probably would have let us go on its own. Ever since, I've been particularly wondering about that feature. I have a much harder time finding information on that than I do whirlpools. Usually eddy lines are just harmless little features, but this I would call an "eddy rip".

    This experience has resulted in me having a few questions that I can't seem to find a satisfactory answer for...

    • Can a whirlpool or eddy rip (not sure if this is the right name) actually suck down a kayak? Has this ever happened?
    • Are there any books that go into any detail about travelling through tidal rapids? I have Kimantis' books, which are great, but he doesn't go into much detail on tidal rapids.
    • Is a tandem kayak more or less safe in rapids? I can see it's possibly less safe because it's less manoeuvrable, but then again it's also more buoyant as it's a bigger boat.
    • Are these whirlpools and rips a threat to a person wearing a PFD? They look pretty intimidating, but from what I've read it sounds like they wouldn't be capable of sucking down a person with a PFD and even if they do, they would spit you out pretty quickly anyway.

    Typically I'm travelling in a 22' tandem Seaward Passat with my wife. On longer trips, we have it loaded to the gills with gear.

    I really want to get more informed because I want to travel these areas, but I don't want to take unnecessary risks. A few experiences of my experiences were pretty intimidating, but I just can't make up my mind on how real the danger in these areas is.

    I'd love to hear from others about their experience with tidal rapids. Does anyone else travel through them while they are running? Is their bark worse than their bite? Has anyone else taken loaded kayaks or tandem kayaks through rapids?
     
  2. nootka

    nootka Paddler

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    where exactly was this?
     
  3. mick_allen

    mick_allen Paddler & Moderator

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    Greene Point rapids maybe?

    • -suck down a kayak? Has this ever happened? : probably not completely to kayaks with high buoyancy such as ours, but squirt-boat [kayaks]? getting sucked down is the whole point!
      But basicly in the river [ and I presume tidal rapids too] there are lots of situations where 'one' can get sucked down - think undercuts, think logbooms, think holes etc. - Rapidly moving water is powerful. And certainly floating items that have very low buoyancy such as waterlogged logs, people in little 14# floatation pfds, and possbily swamped kayaks may actually be submersed in the turbulent over/under flows. I've been down, and friends have been down. When I was down it was like I was in effervescing champagne and swimming up seemed to take forever.

      -good books- maybe some of the ww books.

      -tandem safe in rapids - depends on skills: maneuvering and good boat dumping skills, most likely less safe as have to account for two. But in marginal conditions, more buoyant and stable.

      -wear a pfd - it saved a friend who had stopped swimming before coming back up.

    edited to add: I don't think any kayaks/pple/stuff get 'sucked down', I think they just are carried along wherever the current goes which is sometimes down: if there's a lot of residual buoyancy such as in doubles or typical kayaks, then there is a strong force upwards as well - for objects that have low residual buoyancy such as a water logged log or body, much less upwards force to counteract the current flow.
     
  4. puddlejumper

    puddlejumper New Member

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    I was mistaken, it was off the North West end of West Thurlow (Chancellor Channel?) as I have marked on the attached image.



    I should also add that this was during a spring tide I think, so the currents we experienced may have been somewhat atypical. Additionally, we were hitting 25-35 kt winds coming from the North.
     
  5. nootka

    nootka Paddler

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    That area has tricky currents.
    NOAA used a current speed of 0.5 Seymour for Current Passage & Race Passage. What date & time were you there?
    Additionally, snow melt or heavy rain causes extra outflow from Loughborough Inlet.

    My take is that local info is highly desirable. I've heard that Hole in the Wall has a massive whirlpool.
    I know that Seymour Narrows, Surge Narrows, and Okisollo Rapids are navigable at 8-10 knots if you know what line(s) to take and have rough water experience.

    Some tandems have less gear space per person, doesn't that imply less buoyancy per person?
    In a tandem you can brace and paddle at the same time.
    The extra length of a tandem is probably an asset wrt bridging a whirlpool.

    It is unknown how deep a whirlpool could take a person wearing a pfd.
    viewtopic.php?f=1&t=1171&p=87760#p87760

    A proper test would need a dummy with the same density as a person.
     
  6. Astoriadave

    Astoriadave Paddler

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    This dummy survived a souse hole after dumping off a raft, on one of the nastier Western Washington rivers (Boulder Rapid), wearing a voluminous Navy Type I PFD. How? By swimming down into the more or less laminar flow beneath the heavily aerated and backflowing water above. I had no trouble swimming down, owing to motivaion from the three or four recirculations before I remembered how we exited the frothy stuff generated by large plunging breakers, body surfing.

    I think 14 pounds of flotation is no barrier to going deep, if the water is turbulent (and aerated) enough.