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Packraft dynamics


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Viewing 10 posts - 1 through 10 (of 10 total)
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  • #1320884
    Michael S
    BPL Member

    @cascadebackpacker

    Locale: Pacific NW

    One of the new found uses for my packraft is fishing. There are times where I use the packraft to get me to a spot along a river where I simply wade. There are other times where I like to fish from the boat. In the cases where I attempt to fish from the boat, I face the following problems:

    Slowing drift:
    Is there is a way to slow the drift of the packraft while still being safe. I'm not keen on the idea of a drift sock in a river where it could get caught on something.

    Stopping:
    There are times when I'm going down the river where I would like to simple stop to fish from the boat (i.e. wading option here is limited). Packraft anchor? I've read about stuffing an appropriate size rock in a stuff sack to use as an anchor.

    Reducing spin:
    In cases where I fish from the boat and stop paddling, the boat can spin pretty freely in wind. Using one hand to fly fish and while using the other hand to straighten the boat with the oar is less than ideal.

    I realize that the packraft isn't designed for the sole purpose of fishing, but I'm wondering if other have had similar problems and solutions to the aforementioned packraft dynamic problems? Thanks for any advice.

    #2135174
    peter vacco
    Member

    @fluffinreach-com

    Locale: no. california

    Reducing spin:

    if you look at how your butt sticks down deeper in the water, vs how much of the mass is in the back too, vs trying to keep it headed down river, it seems that it is akin to trying to shoot an arrow with the feathers on the front, and all mass is in the back.
    there is nothing really keeping the front end pointed the desired front end'y direction.
    the poor things (older ones were worse) are absolutely unstable in the forward direction, but mine are quite happy to stay about 70 degrees out of whack drifting downriver. it can be hard even to take just a picture they wander about so much.

    question :

    does anybody know if when one is drifting on smooth water at say 3mph, are you going EXACTLY the speed of the water, or sliding down a river which comprises a very large ramp, and thusly going a slight bit quicker ?

    cheers,
    peter v.

    #2135182
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    > or sliding down a river which comprises a very large ramp?

    Consider the extreme case of boating over a waterfall (do NOT try this at home, kids): Are you "sliding" over the surface of the water, as you accelerate at 9.8 meters/second^2? The water is accelerating at exactly the same rate so are, at all times, moving at exactly the speed of the water.

    On a 1% gradient river, the boat and water are likewise subject to a small acceleration of gravity, the same for the boat and for the water. For the water, that small acceleration force is balanced by frictional forces on the water against the river bottom and river banks. For the boat, friction from moving through the air dominates. If there was no atmosphere (1) you would die, (2) the river would flash to water vapor, but (3) you would be ever so slightly "sliding" over the water. Just as streamlines of water have shear relative to each other (no slip at the river bottom, increasing speed toward the center of the channel), there would be a slight shear force retarding the boat's ever so slightly higher speed. Here's your basic velocity distribution during laminar-flow in an open-channel:

    open channel flow

    showing how, in the middle of the river, velocity is faster. With drag against an atmosphere, the surface is a bit slower than deeper water. With no atmosphere, the fastest water would be furtherest from any edge – in the center of the channel at the surface. Imagine the raft as more of the same – further from the drag of the river bottom and banks – and ever so slightly faster than the fastest water.

    #2135310
    Tyler N
    Member

    @mantaray

    Locale: Vuur-Gin-Yaa!

    Michael – I've had success w/a kayak anchor (http://www.seattlesportsco.com/productcart/pc/viewPrd.asp?idproduct=2154&idcategory=127) but definitely not "UL". This is good for when I'm basically using the packraft directly out of the car to load fishing gear and hit the water. The current in the Potomac tributaries I frequent can get strong so I would not trust a stuff sack nearby; in theory it sounds good but I think the stitching on most bags would rip w/the tug of the packraft+you+current. Might be a fun test to see the load bearing capacity of a certain stuff sack. Maybe a properly tied knot directly around the rock would work? YMMV – This may work though on calmer bodies**EDIT: Maybe using a fabric deadman stake bag/patch (a la http://www.rei.com/item/725165/rei-snow-and-sand-tent-anchors )would work better since they are designed to handle more tension? Add a few more knots & that just might do it…

    Remaining stationary…still working on that. Other than being mindful of wind+current the only thing I've done is occasionally throw out a 2nd line to shore/anchor points if available. Yeah, I know, definitely not always an option. I've had success using an old drybag for drift sock – I know your OP seems weary of this but wanted to confirm it works.
    2 anchors may be the only way to stabilize a raft in open bodies. Kinda heavy but that might do it.

    #3734116
    Bryon Powell
    BPL Member

    @trailgoat

    Locale: Redrock Country

    Michael, how’d things ever workout with your packraft fishing? Did you find good solutions to your issues? I’ve got a packraft on the way and hope to fish on most of my trips.

    #3734224
    Andy Berner
    BPL Member

    @berner9

    Locale: Michigan

    How about a bag full of rocks or sand?  Only need to carry the bag and rope. Find the rocks and or sticks when needed

    #3734231
    Philip Tschersich
    BPL Member

    @philip-ak

    Locale: Kodiak Alaska

    My main mode of self-powered coastal transportation for many years was a sea kayak. I like making videos of my trips, and a sea kayak is a great platform to shoot video from. From the standpoint of yaw, it’s very stable. Packrafts are absolutely terrible in this regard. It is so amazingly frustrating to try to shoot video from a packraft even in calm conditions. I’ve tried to sort of wedge my paddle in my arm pit and use it like a rudder, but it’s awkward and never seems to work out correctly. I can’t really entertain the luxury of deploying something into the water like a sea anchor and then retrieve it, because I’m handling photographic equipment and need dry hands.

    #3734232
    Bryon Powell
    BPL Member

    @trailgoat

    Locale: Redrock Country

    @Andy, I’ve read that just using a plain old stuff sack might not work, as it’s not built for that wear and tear, but there’s this neat looking collect-your-own-rocks anchor – https://www.nrs.com/squid-lightweight-boat-anchor/pqvd – which also comes in smaller capacities.


    @Philip
    , with regard to yaw, I wonder whether a small “parachute” might work to provide just enough rear drag in flowing water to keep reasonable downstream orientation. I’d love to be in sync with the river for fly fishing, but if moving just a hair slower kept my boat pointing in the right direction, it might be worth it. (Ha, as I’m writing this, the slightest bit of research suggests that my intuitive idea and the sea anchor are one and the same. ;-) ) Fortunately, most of the time, I’ll be hoping to get my hands wet with fish anyway!

    #3756894
    Anthony A
    BPL Member

    @aa24

    Looking for a way to slow down my drift while fishing from my packraft and just found this thread.  I have tried tying an anchor to the raft.  It almost sank me.  I was on a big lake in pretty high wind.  once I got to the end of the rope, all of that tension was stretching/pulling the raft tubes down into the water.   Every wave was coming over the side and pouring water into the boat.  had to pull up anchor in a hurry and then trudge to shore to empty out the boat.  If there was a way to tie the anchor near the very bottom of the boat it probably wouldn’t pull the tubes down as far and might work, but all of my tie down points are high up on the raft.  It’s not something I’ll be attempting again though.  at least not while I’m out in the middle of a big reservoir.

     

    #3756903
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    My long-practiced rule is to never use more than 15-pound test from my kayak (when fishing) because there are things out there that I don’t want to catch.

    I’m thinking the same thing for an anchor.  Find a longish rock, put a constrictor knot around it (a clove hitch but with an extra twist under the top pass of the line.

    Then deploy the rock as an anchor / drag device.  If it gets stuck or wrapped around a log, you can give it a good tug, snapping the line at the rock, and retrieve all the line.

    My fishing buddy is very clear to his wife and others when asked, “How do we raise the anchor to retrieve a man overboard?”.  You don’t, you just cut the anchor line, make the rescue, go home, and buy a new anchor.

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