Pacific Rowboat

Discussion in 'Boat Design' started by Eric Sponberg, Oct 8, 2015.

  1. Eric Sponberg
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    Eric Sponberg Senior Member

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  2. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm surprised he was able to vector into hitting the target, with that stiff south-easter.
     
  3. Eric Sponberg
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    Eric Sponberg Senior Member

    Sharpii2, if you are going to set rowing records, you cannot have a sail on the boat. Indeed, you cannot even have a canvas cover over the cockpit because the keepers of the rowing records see that an overhead canvas could be used as a sail assist--and that is a big no-no.

    Emerson does have lifting strakes just above the turn of the bilge, full length, both sides. The reason for them is to keep the hull well up in the water when sluicing down large waves. The last thing you want to have happen is to have the nose of the boat bury into the wave ahead at the bottom of a trough. The strakes keep the hull up. But they do not take the place of the keel. The keel is there for directional stability and to hold some extra fixed lead ballast, about 200-250 lbs. worth. This was critical in keeping Emerson upright in all conditions--she never capsized!--almost unheard of in ocean rowboat designs. The most she ever heeled was once at not quite 90 degrees.

    .

    The Cp is high to ensure that we had enough displacement within the given length. For a year-long voyage, this boat had to carry 1,000 lbs. of food alone, in addition to all the other gear. You don't want the length to be too long or you won't be able to control the boat very well. We felt that 28' overall was the maximum we wanted to go on length, and the Cp came along accordingly. Recall that I did an extensive parametric analysis in the early stages of the design in order to establish all the naval architectural parameters. After 11 months at sea, Jacob had about one month of food left.

    This is a done deal--the voyage is finished, it's all over! Yes, the boat is equipped with two watermakers, the main one electric powered by the batteries and solar panels, the other a hand-powered back-up. The watermaker worked flawlessly for the whole voyage. Jacob would run the watermaker about every 4 days to replenish his built-in water tanks.

    I hope that enlightens things. See the early pages of this thread to read more about what went into the design.

    Eric
     
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  4. Eric Sponberg
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    Eric Sponberg Senior Member

    Well, he was originally targeting Marlin Marina in downtown Cairns. The high winds from the SE prevented that, so the next target was Yorky's Knob Boat Harbor about 9 miles further to the northwest. But within about a mile of that target, he saw he was not going to make it through the channel into the harbor, and so he elected to head straight for Trinity Beach, about a mile further north. So a bunch of us on shore hopped into our cars--press, support team, on-lookers--and shot up the road to Trinity Beach as fast as we could. We got there just as he was hitting the sand. Fortunately, there was plenty of sand to cushion the landing and a lot of on-lookers totally amazed that this strange craft was coming onto the beach. But they quickly learned that the boat had come from America and they lent their hands to help the boat make the landing, and then get off the shore under tow to go back to Yorky's Knob Marina. It was blowing 20-25 knots for quite a number of days leading up to that, so the sea was pretty well developed. The boat does have a fair bit of windage, which is probably its weakest feature. It was quite difficult for Jacob to row into almost any kind of wind. But it goes downwind really well.
     
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  5. Mr Efficiency
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    Mr Efficiency Senior Member

    He seemed in remarkable condition in the video, after bobbing around out there for so long. Did he strike a lull in the weather, getting past the reef ?
     
  6. Eric Sponberg
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    Eric Sponberg Senior Member

    Yes, Jacob was in great shape. Mostly because he knew how to take care of himself with the help of a nutritionist and a personal trainer that he consulted before departing. But I'd like to think that the boat design made for "easy living," if you will, while underway. He could sleep comfortably, he could stand up in the forward cabin and in the cockpit, he could cook easily and stay dry, or dry out easily if he got wet. He would wash with fresh water several times a day just to keep the salt off his body. I am very pleased that he fared so well--this is what we set out to do.

    The wind did not really let up too much for a few weeks before he came through the reef. There are plenty of passes that are some miles wide for getting through the reef, but it was a matter of picking the right one at the right time to get through considering the prevailing winds and currents.
     
  7. sharpii2
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    sharpii2 Senior Member

    Well. I see he made it, and the boat is still intact. So the proof is in the pudding. Congrats to both you and him.
     
  8. RHP
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    RHP Senior Member

    Wonderful achievement, congratulations to Jacob and of course the designer and builder!

    The support team you need to make a venture like this come off smoothly must be immense... further congratulations to all involved.
     
  9. Eric Sponberg
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    Eric Sponberg Senior Member

    The support team consisted of a few family members and friends, basically, plus a nutritionist and a personal trainer. Not too hard.
     
  10. kerosene
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    kerosene Senior Member

    I really doubt your claim. 0.250hp is 186W. Double that is 370W.
    On a concept2 rower 370W equals 1:38 500m time. 1:45 is 7 minute 2,000m which is NOT easy - and 7 minutes, not a year.

    World's last season's best ranked 100km row took about 6 hours with average of about 260W.

    It is not even close to realistic that day after day effort could come even close to the world's best heavy weight ultra distance rower's 6h output let alone be 100W more.
     
  11. kerosene
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    kerosene Senior Member

    And huge congrats to everyone involved. I cannot comprehend the steel mind required for a laborous 330 day voyage.
     
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  12. waikikin
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    waikikin Senior Member

    Hi Eric,

    I happened to be in Cairns the last week & got a real buzz from the story when it came up on the news.
    Congratulations to Yourself the Builder & Jacob plus team. Remember some earlier vids & seemed pretty together.

    All the best from Jeff
     
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  13. sharpii2
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    sharpii2 Senior Member

    A really good point, Kerosene.

    At the risk of being a spoilsport, I'll add that this voyage was likely more a sailing one than a rowing one. Here's my reasoning:

    1.) Much of the trip was in the southern ocean where the winds are often fierce. Probably less than 200 w of sustained output is not enough to move a 1.6 mt boat in much more than a calm. Rowing upwind in winds more than say 16 kts is probably only possible for just short bursts of maybe an hour or so, and I feel that's being generous at that.

    2.) This boat is equipped with a substantial keel which had a surface area of somewhere around 20 sf if not more. At the 20 sf number, it would have been able to provide adequate leeway prevention for at least 300 sf of sail by my calculations. This keel is of a "drag"design with a bottom edge which slopes up to the hull at the bow. This keel has a sailboat-like rudder attached to its trailing edge. Granted, a rudder this large is needed for the slow speeds this boat was likely to achieve using it's chosen propulsion method. It also likely provides excellent control while surfing down waves. And, on top of that, it also probably provides a 90 degree range of downwind course choices (45 degrees to port plus 45 degrees to starboard).

    3.) With these two facts in mind, it is possible, if not very likely, that this boat could have made it to Australia if Mr. Henderson had not rowed a single stroke. It is much more likely that the rowing came in handy during calms and as a means of expanding the choices of downwind courses. This may have made all the difference between getting from one favorable current and/or wind pattern to another. But, as dilligently as Mr. Henderson endeavored, this may be all that it did.

    So, even though I don't consider a boat to be a sailboat unless it can return to the point it started from with no change in the wind direction, this one may cross the line because, even though it had not one scrap of sail, and even though it's above-water hull was designed to be a slippery aeordynamically as possible, it probably was primarily driven by the wind.

    So, when it comes to rowing records, I think we should be a bit more careful.

    Should we have some sort of standard for which percentage rowing acounts for the boat's total propulsion during the voyage?

    This being said, I believe Mr. Henderson and Mr. Spongberg deserve a great deal of credit. Mr. Henderson endured and rowed his heart out. Mr. Spongberg designed him a safe, seaworthy boat to do it in.
     
  14. BlueBell
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    BlueBell Ahhhhh...

    Two points: ( I am a personal trainer and a human power boat designer/builder/competitor/race winner. )

    1.) Gym equipment is notorious for over estimating power output.
    Do not rely on the actual numbers displayed as being accurate, they are not.
    2.) The average, sustained human output is ~100 watts at the prop and not that much more for a well trained athlete.
    This is not 30 second output, not 30 minute output, but sustained, continuous output for hours, days, weeks, months!

    Good on Eric and Jacob!
     

  15. Dolfiman
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    Dolfiman Senior Member

    You are right, the wind and the currents are an important contribution. This observation was made by several ocean rowers like Gerard d'Aboville (Atlantic crossing in 1980) to objectively put their performance into perspective, and finally a transatlantic race was organized to channel the performances in a common referential: the Rames Guyane, from St Louis of Senegal to French Guyana, a kind of Route du Rhum but for rowers. The rowing boat is a 8m long monotype (beam 1,60m, light weight 450 kg, 750 to 1000 kg in charge depending of the crossing time envisaged), designed by Jean-Michel Viant, 4 editions of the race were performed (2006, 2009, 2012, 2014) , the 2018 was cancelled due to organisation issue.
    The boat : Frederic CORVESTE | RAMES GUYANE 2017 - Course transatlantique http://pack.graphsite.fr/skipper/bateau.html
    The start of the 2009 edition :

    Mathieu Bonnier, 47, veterinary up to now, was second at this 2009 edition, then he prepared another rowing expedition, the North-West route, did it partially in 2010-2011 (actually he stopped at Cambridge Bay after 2500 km) with another rowing boat concept, Liteboat expedition, designed by Sam Manuard : TipTopToo, minitransat 6.50 et autres voiliers de croisières modernes http://sam.manuard.free.fr/
    Video with some beautiful sequences in the icy waters :

    ... and finally he founded the (successful) Liteboat company, a beautiful change of life :
    LiteBoat - Light, stable, easy rowing boats! https://www.liteboat.com/
     
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