Can a Thames Rowing Skiff "make it" in the Blackburn Challenge?

Discussion in 'Boat Design' started by SailorDon, May 12, 2013.

  1. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    There are several current designs of the Thames Rowing Skiff design concept. I own one of them, the Selway-Fisher Mandarin 17. My boat was built by Paul Kirwin of Sugarland, Texas.

    [​IMG]

    The question is, would such a design be suitable for entering (and hopefully finishing) the Blackburn Challenge?

    By "such a design" I mean that it doesn't have to be the Mandarin 17, nor does it have to be 17 feet long. But it has to look like a traditional Thames Rowing Skiff.

    [​IMG]

    The passenger seat backrest and armrests would be removable for performance competitions and installed for show competitions.
    Fixed seat design, modifiable to single or double rowing.
    Thule posts would be replaced by bronze oarlocks.

    Here are some performance observations from having rowed my Mandarin 17 for 98.2 miles over the past 37 days since I bought my rowboat.
    1. It rows easily up to 4.5 mph and then the gain in speed from additional rowing power rapidly diminishes.
    2. The side-to-side rolling in a beam sea makes it very difficult to keep both oars in the water.
    3. Rowing without the rudder is OK for no wind and smooth water. With even light wind and small waves, it will fishtail. Rudder required.
    4. The bow pounds too much when going into 1 foot or higher waves. It doesn't slice through the waves.

    It is my personal feeling that I am hitting a performance wall of wave making resistance at 4.5 mph with the Mandarin 17. I am curious if a 20 foot version would improve my performance by swapping a little bit of extra skin friction drag for a big reduction in wave making resistance. Maybe I could get a steady 5.0 mph from a 20 foot version.

    Here is the GPS data download from this morning's rowing exercise:

    [​IMG]

    Towards the end, I am unsuccessfully struggling to keep 4.5 mph.

    If a 20 foot version of a Thames Rowing Skiff is suitable for the Blackburn Challenge, I might seriously consider having one built for the 2014 challenge.

    I would install canvas covers over the large open bow and stern areas for the open water coastal rowing.

     
  2. keith66
    Joined: Sep 2007
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    keith66 Senior Member

    Thames Skiffs vary quite a lot but most of the old ones are not really designed to be good seaboats. Every year a goodly number enter the Great river race and its not unknown for one to get swamped. Most wear long forward spray decks for the day!
     
  3. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    Rowing in 20 mph wind

    After rowing in 20 mph wind yesterday on Lake Livingston, I believe I answered my own question. Here is the video of the rowing experience.



    I don't believe Thames rowing skiffs in general are suitable for coastal rowing. They are really designed for flat water.
     
  4. NoEyeDeer
    Joined: Jun 2010
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    NoEyeDeer Senior Member

    That is flat water. Well. close enough to it. :)
     
  5. SailorDon
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    SailorDon Senior Member

    I was just practicing in case it gets a little rough like this:

    [​IMG] :D [​IMG]
     
  6. acp1934
    Joined: Apr 2007
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    acp1934 Junior Member

    That is a pretty boat SailorDon, but yes I agree, that's not rough water. If you want to row the Blackburn, why not build a different design for that and enjoy your skiff on the lake?
     
  7. SailorDon
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    SailorDon Senior Member

    I don't think a "built for purpose Blackburn Challenge" rowboat is in my future. The concept came to me as I became hooked on the Thames Rowing Skiff design and my agenda was to see if there was anything that could be done within that design concept, about 20 feet overall length, that could survive and finish the Blackburn Challenge.

    The concept came to me when I realized I could row my Mandarin 17 (a sort of mini-Thames Rowing Skiff) for 4 miles at an average speed of 4.7 mph
    [​IMG]
    All I have to do is build up my endurance so I can go 5 times that long, and of course pray for flat water. :D
     
  8. NoEyeDeer
    Joined: Jun 2010
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    NoEyeDeer Senior Member

    Yeah that's a tad bit choppy. :D

    Problem with Thames Skiffs is that they were built for the upper Thames, where the biggest wave you're likely to see is about three inches high during a gale.
     
  9. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    After 200 miles of rowing - no Blackburn Challenge

    After rowing my Mandarin 17 Thames Rowing Skiff for 200 miles over the past 3 months, I have concluded that it is not suitable for competitive coastal rowing.
    Here is a screen capture from a video from yesterday morning's rowing exercise.

    [​IMG]

    Unfortunate that the camcorder was fixed on a tripod so the shot only shows the first 3 feet of the boat slicing into the wave.

    Here is the video from which the screen capture was taken.

     
  10. messabout
    Joined: Jan 2006
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    messabout Senior Member

    Don; the graphs indicate that you are rowing at very near the theoretic hull speed of the boat. You could probably get an extra half knot or so if the boat kept the same width and grew to 20 feet. There is the possibility that the bottom could be tweaked a bit so that you could optimize prismatic coefficients for the upper end of the speed range and such stuff.

    I reckon, judging from the video, that the boat is not happy in lumpy water. As mentioned above, the design anticipates fairly smooth water. It would be prudent to forego the adventure of coastal rowing.
     
  11. Lister

    Lister Previous Member

    Feathering the oars will help a great deal.
     
  12. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    It is true that when rowing into the wind, I feel signficant wind resistance on the oars during the glide part of the stroke. I have not mastered the art of feathering the oars on the glide stroke. My wrists don't want to rotate that way. :(

    Here is a GPS plot of a recent 2.5 mile rowing exercise. I didn't write it in the log, but I'm guessing 10 to 15 mph wind out of the south.

    [​IMG]

    I start out at around 5.0 mph with the wind. At the turning point, the waves and wind are on my port beam which slows me down to 4.5 mph and as I align more directly into the wind and waves, I have difficulty maintaining 3.5 mph. As I head for home with the wind and waves on the starboard beam, my speed picks up to 4.5 mph again. 4.8 mph for the home stretch (I was tired by that time).

    I'm think for me to make a serious entry in the Blackburn Challenge, I need a rowboat more like the Savo 650S.

    [​IMG]

    This design is far different than what I was hoping to do with a Thames Rowing Skiff.
     
  13. Clinton B Chase
    Joined: Mar 2005
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    Clinton B Chase Senior Member

    As to whether the skiff will make it, I think more about the ability of the oarsman and the flotation in the boat...is it enough to self-rescue and are you skills sharp enough to avoid getting in that situation in the first place.

    Regarding the Savo...I think the same can be said...not so sure the design is inherently better than than the skiff. The Savo is much higher sided, so more windage, but the wetted surface is lower. Incidentally, I am working on a design that I hope will be inherently ideal for open water racing.

    See the "designing a fast rowboat" thread. I have rowed the Savo in Finland. It is a really nice, nice boat but I think it is intended for sheltered lakes. Chop is no problem, but around Cape Ann you can get into more than chop....you get chop on top of wake on top of wind generated waves before the wind shift to a new wave pattern from the new sea breeze, all on top of a swell.

    So, the Savo and Thames are equally unsuited for the BBC from the stand point of the intended waters of the original design. But the same can be said of the Adk. Guideboat.

    So, it really comes down to whether the boat is fast and whether the oarsman can handle the boat and conditions.
     
  14. petersont
    Joined: Dec 2010
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    petersont Junior Member

    Savo & Blackburn

    This all becomes less theoretical in a few weeks as a Savo is registered to race in the next Blackburn ( as a double ).
     

  15. bpw
    Joined: May 2012
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    bpw Senior Member

    Depends on the year, I have done the Blackburn a few times in kayaks, One year it was glassy calm the whole way around and full on racing shells did fine (and set course records).

    Another year they had to rescue so many people the coast guard told them never to run the race in those conditions again. 6 man outrigger canoes where flipping along with many of the shells. Lots of kayaks dropped out. Seas where 4-6 feet and 15 knot plus winds. I went surfing that evening after the race and good harbor was head high plus.
     
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