plywood boat hard to row

Discussion in 'Boat Design' started by cmitchelld, Jun 17, 2014.

  1. cmitchelld
    Joined: Jun 2014
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    Location: porters lake nova scotia

    cmitchelld Junior Member

    hello all,
    i am new to the forum, first post as well.
    so i have a dilemma, i built myself a 10' scow for fishing.
    i was out in it today and i am having a hard time keeping it straight and it seems cramped while rowing. it could be me, but it seems i have to row twice with my left then my right. i don't know what information people need but this is what i can tell you at the moment, i can also send pictures to anyone that is interested.

    length: 10'
    width: 34"
    ore's: 65"

    thanks.
    cheers mitchell.
     
  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    You might want to add a skeg to the bottom near the stern to increase directional stability.
     
  3. philSweet
    Joined: May 2008
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    philSweet Senior Member

    You can post the pictures right in the thread by clicking on the "go advanced" button at the bottom of the post or reply page. There is an attachments manager at the bottom of the new screen. A separate window appears that lets you upload photos and other stuff. You can also paste stuff from the web, link to videos, etc. Welcome to the forum.
     
  4. thudpucker
    Joined: Jul 2007
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    thudpucker Senior Member

    Pictures would help. You may not have enough of an arc to the bottom.
    Pushing water with the prow will make the boat go crazy.
     
  5. ancient kayaker
    Joined: Aug 2006
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    ancient kayaker aka Terry Haines

    You could try a skeg to keep it running straight, just a piece of 6" x 12" clamped to the transom would serve to find out if that is needed before you undertake real work. If the transom isn't dragging (see 3rd para) the boat may be down at the head. That will cause the bow to catch and want to swing to one side or other. You can move weight aft including yourself, or if that is not practical try the skeg.

    In poorly designed plastic kayaks there is often a tendency for the boat to swing arbitrarily to one side or the other once it is under way, and the unfortunate paddler spends lots of energy pulling on one side to keep it straight. Such boats need a foot-controlled rudder or skeg.

    As far as being hard to row, first question would be, is the boat left in the water or dry-docked? If it is saturated it will be heavy and weight translates to drag in any boat. Of course there may not be much you can do about that but it will lower the boat in the water: see next paragraph.

    If the boat is water-logged, the next place to look would be the transom height above the water. If the transom is dragging it will slow you down and create noise: do you hear gurgling sounds from the stern? If so, move your weight and/or anything else heavy forward or remove heavy objects stored near the stern. Use a stool if necessary to find the best rowing position.

    Finally, we hope, rowing position. You say you feel cramped. The best advice for that would be to Google "Rowing Position" or try -
    Rigging a Rowboat

    The things you can do include move the seat (we like to call them thwarts around here) or re-position the oarlocks on the gunnel, or raise the oarlocks if you need more knee room - or move the foot brace.

    Your oars seem about right length for the size of boat, it's determined by the beam - assuming there are no outriggers that is.
     
  6. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    A boat with those dimensions should row fairly easily. It will not be fast but it should go smoothly without gut wrenching effort. One of the things that you have not told us is whether the boat has sufficient aft rocker. ............explanation below.

    A displacement boat, one that is to be rowed or moved through the water at a conservative pace, needs to have it's bottom, at the transom, rise to the waterline or slightly above. That means when you look at it from the side, the bottom will curve upward as it goes from about the middle of the boat to the back end.

    If your boat has the planing configuration where the bottom goes straight back, without the rising bottom curve, you will have to put extra effort into rowing. The transom will be dragging. That condition can cause the boat to behave oddly. It is not reason enough to burn the boat but it is just not a rowing boat.

    One more reason that the boat may not want to go straight is weight distribution. If you sit just a little bit to one side or the other, the boat will want to turn toward the side opposite of the offset weight. On a narrow boat like this one you will need to be very aware of the left to right balance while rowing. As a matter of fact, you can probably steer the boat with this method if you experiment with your body position.

    As mentioned above, a skeg is probably worth trying.

    Post pictures if you can.
     
  7. cmitchelld
    Joined: Jun 2014
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    cmitchelld Junior Member

    hey guys thanks a ton for all the reply's. i have not gone through it all yet but i will attache some pictures of the boat.
     

    Attached Files:

  8. cmitchelld
    Joined: Jun 2014
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    Location: porters lake nova scotia

    cmitchelld Junior Member

    i realize now that these pictures probably are great for the questions i am asking, i will retake some tomorrow, it is getting dark now,
    as for the dragging stern, i think you guys are right, i only swept the stern up a few inches,
    i do believe that the depth dimensions where, from stern to bow:

    11.5" 14" 7"

    i do not hear any gurgling at least at the speeds i am rowing at.

    the boat is put on a brow every time its not in the water so it is not water logged at all.

    i will go through the rowing positions after i send this off,

    and i will defiantly try and skeg if i cant figure anything else out, like it was said i will mock it up first and see how much of a difference it makes
     
  9. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    I'd just reiterate what the others have said. A skeg will make a huge difference, particularly as you have a parallel sided boat. Also if you are not sitting dead on the centre line you'll veer one way or the other. You can check that easily, simply by stopping rowing and see if the boat coasts to a stop in a straight line

    Richard Woods
     
  10. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    If the boat is pulling to the one side continually, it suggests either the boat is not "true", the weight distribution (including occupants) is uneven, the rowing strokes are uneven, or some combination of the three. The bias to the one side is the key information, it is not dodging around this way and that. As for being hard to row, that is a subjective assessment, I'd suggest sandbagging the bow to the point the transom leaves the water to see if it moves more easily, though you will probably have a worsening of the directional instability.
     
  11. cmitchelld
    Joined: Jun 2014
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    cmitchelld Junior Member

    Ic thank you, I will try sand bagging the bow tomorrow when I get up, also I will try and rig up a skeg, I will let you all know how I make out tomorrow. Thanks again
     
  12. philSweet
    Joined: May 2008
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    philSweet Senior Member

    If possible, shave down the chine strakes forward of the seat. Maybe glue a chine log onto the inside in its place. Those forward strakes (chine runners) are a big part of the problem. Basically, any skinny shape like that wants to turn broadside to the flow if perturbed the least little bit. Not nearly so bad if its just a fat flat bottom plate that's off line a bit. And add the skeg, too, or make the chine runners aft deeper. But shaving down the bow strakes is three or four times as important. By the time the water gets back to the stern, it has largely aligned itself with the boat anyway.
     
  13. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Maybe I'm missing them, but I cannot see any stretchers - foot braces, in the hull. These will help your body stability and help hold a reasonable rowing position. Again the comments above are all valid. One other thing is if there is too much rocker, the boat will want to spin a bit like a top, around your central weight. Sandbagging ie adding load may well improve it and also prove that she is a bit feisty when lightly loaded.

    The purpose of a skeg is to help prevent this spinning and retain directional stability.

    If the hull shape had been curved in, in top plan elevation she would have been a little better behaved. Check the old Dory type French and N. American fishing craft. They can row quite well.
     
  14. cmitchelld
    Joined: Jun 2014
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    cmitchelld Junior Member

    there are no foot braces in place i am trying to keep the inside of the boat as clean as possible for fishing and carrying gear.
    and if i am not mistaken are you referring to the rubbing strips under the boat as the chines?
    i can defiantly sand those down and make them tapper more to the stern.
     

  15. ancient kayaker
    Joined: Aug 2006
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    ancient kayaker aka Terry Haines

    The sheerline (top edge of gunnel) looks straight. Therefore, from your measurements of depth stern (11.5" midships 14" bow 7") the rocker would be approximately (11.5 + 14)/2 - 7 = 5.75" which should be adequate for a flat-bottomed boat of that size to keep the transoms above the water. However the stern is significantly lower than the bow and is only 3.5" above the lowest point of the bottom. If that is less than the draft then it will drag. Lowering the bow is going to look a little strange but should help while rowing. Also if you add a skeg it would work better if it is in non-turbulent water.

    The runners along the chines* would make the water curl around as it tries to exit the bottom to the side and turbulence will result, which will further increase the drag of a less than streamline craft. Reducing their thickness and/or rounding their edges may help: I wonder what do the experienced boat guys think of that idea?

    I had a flat-bottomed skiff with a similar stern although it had a conventional pointed bow, and it rowed extremely easily, however it was more lightly built. I could see the wake, it was quite flat with very slight swirls, actually smoother than the water I was rowing through. There is an art and a science to designing a flat-bottomed boat that I think your boat has not benefited from . . .

    * chines are the longitudinal edges of a hull, the term does not apply to hulls that are rounded.
     
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