New member here interested in rowboats

Discussion in 'Boat Design' started by SailorDon, Apr 8, 2013.

  1. terhohalme
    Joined: Jun 2003
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    Last edited: Apr 11, 2013
  2. Dirteater
    Joined: Oct 2010
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    Location: Canada

    Dirteater Senior Member

    very nice :cool:

    I"m guessing somewhare around 73 miles per hour! :D
     
  3. SailorDon
    Joined: Apr 2013
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    Location: Livingston, TX

    SailorDon Senior Member

    No 73 mph. Not in my 17' Mandarin.


    But one of my Biker Buddies has a 770 hp supercharged Eliminator. That will go 73 mph at 1/2 throttle.

    [​IMG]

    My maximum speed (per Garmin GPS) in my Mandarin 17 is 6.3 mph. Of course that was not a sustainable speed and it was downhill with the wind. :D
     
  4. NoEyeDeer
    Joined: Jun 2010
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    Location: Australia

    NoEyeDeer Senior Member

    You're not rowing too hard. The rowlock blocks are too weak. They take a lot of load.

    My 2c: move them around until they're in the right location for you, then set the screws in epoxy. That will give much better strength than just threading them into wood. You could also use wider (athwartships) blocks to reduce the stress on the fastenings. Length looks ok.

    Clinton Chase (builder of Drake) rows a hell of a lot and is about your size. If you use the same measurements as he uses, you should be fine.
     
  5. Dirteater
    Joined: Oct 2010
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    Location: Canada

    Dirteater Senior Member

    I too love those downhill lakes! (you don't even have to row *LOL*)
    my 73 mph was referring to terhohalme's vid.
     
  6. viking north
    Joined: Dec 2010
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    Location: Newfoundland & Nova Scotia

    viking north VINLAND

    I'm not familiar with rowing your style of craft but generally on dories the oarlocks are from 10 to 12 in. aft of the aft edge of the rowers seat. One other suggestion just for the heck of it try a set of 9 or 10ft. oars. Longer oars while slowing down your SPM (strokes per minute)will increase the length of the power stroke thus increasing distance travelled under this part of the rowing cycle. Also the blades should enter and exit the water at from 10 to 15 deg. of angle. This gives you an nice smooth entrance and exit reducing turburlance and drag. The other added features are it helps offset skipouts during entry if the water is rough plus reduces that annoying wave grabbing an oar during the glide cycle. The tilted blade rides up and over the oncoming wave. As i've said prev and also mentioned by several posters here it will all become so natural you'll look forward to your afternoon "In The Zone Nappies :D
     
  7. SailorDon
    Joined: Apr 2013
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    Location: Livingston, TX

    SailorDon Senior Member

    I moved my oarlocks aft 6". What an improvement. I might have overdone it by an inch, but now I can really apply my upper body strength to the full sweep of the power stroke. I'm still learning!

    I rowed 2.2 miles this evening with the oarlocks in the new position.

    I'm not sure that changing the seat height would be beneficial. During this evening's rowing adventure, I slapped a wave or two on the glide (back) stroke. And I was almost dragging my knuckles on the floorboards. In a beam sea, this puppy really rocks and rolls. Takes a lot of timing to get your power stroke into the wave instead of the trough. And of course that interrupts the stroke rhythm.
     
  8. petereng
    Joined: Jan 2008
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    Location: Gold Coast Australia

    petereng Senior Member

    Sailor Don - Im interested in comments on your rudder. Have you used it? do you use it while rowing or is it to set for cross current it cross winds. I'm designing a rowboat at present and want to put a rudder on it but it does not seem to be the traditional thing to do? or is it so you can put a small sail on the boat? Regards Peter S
     

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  9. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    I can certainly answer your question on if I have used my rudder on my Mandarin 17. The answer is an emphatic "YES". I'm just relating my personal experience here.

    [​IMG]

    The history of the Thames rowing skiff is that they are designed with a rudder. See Wikipedia: http://en.wikipedia.org/wiki/Thames_skiff

    Personal experience is that on flat calm water with no wind, the Mandarin 17 handles fine without the rudder.

    See my video at: http://youtu.be/FcIaKiu6qmI

    When the wind and waves pick up, I find the rudder is necessary to maintain a straight course. Without the rudder in 2 foot waves, this puppy wanders all over and may get the attention of the lake patrol who might want to issue you a citation for RWI (Rowing While Impaired). :D

    If you could guarantee calm flat water with no wind, the rudder is optional with this design IMHO. The reality is I have to use the rudder when the wind and waves push the stern of the boat from side to side.

    You might consult with the builder of my boat, PicniK Yacht. He has a lot more design experience and a lot of history of the Thames rowing skiff design (including the connection with Pink Floyd's "Signs of Life").

    He told me he scans boat building websites, so he might respond to this post. If you want, I can send you a PM with his business card. I don't want to post it here because of the possible commercial advertising connotation.
     
  10. petereng
    Joined: Jan 2008
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    Location: Gold Coast Australia

    petereng Senior Member

    thanks sailordon - no need to contact Picnic, just want some reinforcement for me to go the way of a rudder. Any details on the rope system? Do you pull these by hand or foot? Do they slip and grip or do you have to hold them somehow? Peter
     
  11. SailorDon
    Joined: Apr 2013
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    Location: Livingston, TX

    SailorDon Senior Member

    The rudder control is two ropes fitted to each end of the beam on top of the rudder.

    [​IMG]

    As you can see in the photo above, I have used Figure 8 stopper knots in the backrest of the passenger seat to keep a very slight tension in those ropes to keep the rudder amidships. I have never used the rudder to steer the boat, only to keep it on a straight course.

    [​IMG]

    The design does allow for a coxswain to steer the boat if you are rowing doubles, or coaching a solo rower. The builder supplied two wooden hand grips, but I put them in storage since I don't plan to use the rudder for changing direction of the boat.
     
    Last edited: Apr 13, 2013
  12. SailorDon
    Joined: Apr 2013
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    Location: Livingston, TX

    SailorDon Senior Member

    The moving aft by 6" of the oarlocks definitely helped my rowing performance on my Mandarin 17. Here is a GPS log of my 8.3 miles of rowing this morning. I was really hoping for 10 miles, but at 7.8 miles I started to fade.

    [​IMG]

    This evening, I rowed another 2.4 miles with a 2" thick life cushion on the seat. Of course I sat up 2" higher, but it did not improve my rowing performance. It also raised the center of gravity. I will stay with the rowing seat at the height "as built".

    I find that my rowing speed is about 4 mph. At 3 miles on the speed chart the velocity is less because I had to keep swiveling my head around to look for submerged tree stumps. That part of the lake up by US 190 is like a minefield of tree stumps. I need a rowing mirror.
    .
     
  13. petereng
    Joined: Jan 2008
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    Location: Gold Coast Australia

    petereng Senior Member

    Rowing Boat Mirror

    Here is a friends mirror works great! Wouldn't row around here without one, power boats, markers and small boats... . Peter S
     

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  14. Easy Rider
    Joined: Oct 2009
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    Location: NW Washington State USA

    Easy Rider Senior Member

    What boat cross section has the less resistance?

    Strait V.
    Rounded like Mandarin w/o the chines.
    Concave or "wineglass" section.

    I'm thinking a straight V w rounded chines but ????

    Of what importance is it to get the displacement close to the C/L?

    It would seem wetted surface and wave making forces would battle for supremacy on this issue. But at 3 or 4 knots wetted surface would seem more important but I have the feeling it's not that simple.
     

  15. troy2000
    Joined: Nov 2009
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    Location: California

    troy2000 Senior Member

    I've always thought that if I were to build a rowboat for pleasure and exercise, I'd go with Joel White's 20' Bangor Packet rowing wherry. It'll probably outrun anything except racing shells or their close derivatives, but it'll handle rough water better than they do.

    http://www.youtube.com/watch?v=8jGebAwFM2s

    http://www.flickr.com/photos/nwswb/sets/72157626421882031/

    I had a heck of a time finding the boat online, because my memory kept insisting that Joel had named it the Bangalore Torpedo (and yes. I know what one of those is, ordinance-wise).

    It's a medical problem; my doctor's diagnosis is that I have a full-blown case of CRS. You know.... 'Can't Remember S***.' :p
     
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