Pacific Rowboat

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

  1. RHP
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    RHP Senior Member

  2. waikikin
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    waikikin Senior Member

  3. Eric Sponberg
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    Eric Sponberg Senior Member

    I haven't been able to figure it out either.
     
  4. waikikin
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    waikikin Senior Member

    From Ocean rowers site ".........."
    http://www.oceanrowing.com/guidelines.htm

    " Wind generators:
    After the following comment from Rusty Knowler of Southwest Windpower USA. (and in the absence of any conclusive data saying a wind generator can help advance a ocean rowboat)
    ORS accepts that a wind generator is optional equipment for an ocean rowboat.

    From: Rusty Knowler
    To: Michael Seeley
    Subject: RE: AIR Marine 403 or AIR X
    Mike,
    We don't have any good thrust data at low wind speeds, but it is basically zero. I can't imagine it being anywhere close to enough force to move a boat.
    Rusty

    It is still advised by ORS to check self righting capability of ocean row boat once the wind generator is installed.

    Solar panels:
    Should be used for generating power for all electric's on any ocean rowboat.


    UP
    Canopies:
    Not to be fitted, they can hinder or prevent ocean rowboat's self righting action (it has been said by many ocean rowers that they believe a canopy acts as a sail)."
     
  5. W9GFO
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    W9GFO Senior Member

    Well sure, at low wind speeds it won't do much. Neither would a canopy used as as sail.

    If they are talking about a Bimini top type of canopy then sure, that makes some sense. Surely a canopy can be designed to not restrict self righting - especially with buoyant tubes for support like Eric's design. And if not, a sharp knife would rectify that problem. Not to mention that in heavy weather it would be prudent for the skipper to stow it. That same design would not provide any significant thrust - much less than a wind generator.
     
  6. Eric Sponberg
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    Eric Sponberg Senior Member

    Apparently, no one is objecting to our having a hardtop. And while in one sense the hardtop may exacerbate self-righting ability because of the inherent drag of the top moving through the water, in another sense it has net positive buoyancy that actually assists in causing the boat to self-right. We are going to do a roll-over test with Jacob inside the boat, and we'll see just how quickly the boat rolls back upright from total inversion.

    Just to complete the data for all of you reading this thread, I attach PDF printouts of the hydrostatics and the stability curves for this rowboat. You'll note that there is no negative area of stability--all righting arms are positive from 0° to 180°. The slope of the righting arm curve at 180° is very steep, meaning that the boat will be very unstable upside down. If this boat rolls over (correction: WHEN this boat rolls over...) it will come back upright very quickly.

    Eric
     

    Attached Files:

  7. bregalad
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    bregalad Senior Member

    Wasn't it Tori Murden who said if she'd know how much time she'd spend bouncing off the cabin top she'd have put much more thought into it's design and padding?
     
  8. Clarkey
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    Clarkey Senior Member

    I also remember reading accounts of the ring frames in the cabin area of the Morrisson boats being rib-breakers for people thrown around in heavy weather.
     
  9. RHP
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    RHP Senior Member

    Roz Savage abandoned her first trans Pacific attempt if I recall correctly after rolling a few times within a short period of having left the West Coast of the USA. She subsequently added external ballast to her keel. The Brocade was a carbon Morrison solo boat. Good link here.. www.rozsavage.com/contents/rozs-boat-the-brocade/

    Understanding better now Eric's explanation of the centre of pitching, I would be inclined to extend the aft cabin forward if possible and shift the rowing position if technically sensible. As you can see I'm a virgin in a Hells Angel bar when it comes to the practicality of yacht design! I would also increase the fore cabin structure height to create better weather and wave protection.

    I was sad when this boat sold so quickly despite being a plywood boat I think she is more than capable of doing the job and had already received a rebuild with sensible modifications:

    http://www.oceanrowing.com/sale/Macpac_photos.htm

    I was playing with the idea of buying her however she went too quickly!
     
  10. Eric Sponberg
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    Eric Sponberg Senior Member

    That is correct, and that is one of the things I helped Tori change in her rebuilt boat. She is a tall lady, and the main (aft) cabin on the Morrison boat is rather small for her by comparison. She did sustain rib and/or back injuries on her West-East Transatlantic attempt, if memory serves. When she asked me to redesign her boat for her 1999 East-West attempt, which mostly involved simply repairing it, we got help from The Challenge Business, holders of the Phil Morrison design, who sent me some of the AutoCad design files for patterns of selected hull panels. I redesigned the aft cabin to be built with foam-cored plywood panels--which got rid of the internal ribs--that were also bigger and rendered the cabin a few inches taller. You can read about this effort on my website here:

    http://www.sponbergyachtdesign.com/Americanpearl.htm

    Note in the story the sketches that I contemplated for a new boat for Tori--it has design elements of the Pacific Rowboat in the form of the wine-glass sections, larger cabins, fixed poles over the cockpit, and a canvas top--which I later found out was a non-acceptable feature, as we have discussed above.

    Eric
     
  11. Eric Sponberg
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    Eric Sponberg Senior Member

    RHP, There are some design guidelines (rules, if you will) promulgated by New Ocean Wave for their racing boats, for overall height. The stipulations of these rules could be debated ad infinitum because to me they are not necessarily logical. However, reading between the lines and trying to follow their philosophy, they eschew boats that are too tall, with a maximum height of 56" above the load waterline. The Pacific Rowboat, not including the plastic dome over the main cabin, is 54" above the design waterline. The design guidelines also stipulate a maximum distance allowed between cabin heights as between 8" and 21". There are different stipulations if the bow cabin is higher or the stern cabin is higher. Again, I am not sure I can figure out why, but its a guideline that can be studied, which we did.

    The other requirement that Jacob was adamant about was being able to see over the stern cabin from the rowing seat. After we adopted the concept of the hardtop over the cockpit, we had to put a sloped section down to the after cabin and fill this with windows so that we could meet this requirement. The aft cabin is meant for utilitarian purposes--this is where the batteries are, the Porta-Potti (which Jacob may discard in favor of a bucket with a suitable seat on it), and spaces to store food and spares. The forward accommodation is where he is going to live, so we are trying to make this space as comfortable as possible.

    One of the late changes in the design was the internal shelving--Jacob wanted shelves to store stuff along the sides of the cabins. So I designed fiberglass-foam core structures for the shelves. As the builders reviewed the design at that point, one came back with the excellent suggestion of ripping those out and replacing them with canvas shelves that could be hung on the sides. This had three huge advantages: 1, simpler and less expensive construction; 2) elimination of a few hundred pounds of weight in an already heavy boat; and 3) They provide built-in padding for Jacob as the boat rolls over (WHEN it rolls over). Most of the stuff in the shelves will be soft goods like clothing and other lightweight stuff.

    Speaking of storage, we don't know precisely how much space most things will take up until Jacob starts packing gear away. Water we know about--we have two built-in fresh water tanks. For food, Jacob received some powdered and freeze-dried food, some from his food sponsor, Soylent, and he packed as much as he could into two plastic shopping bags. Then he weighed them so that I knew what volume and weight density they had. Correspondingly, I calculated the volume of every storage space in the boat below the main decks and determined that we could readily pack in the maximum amount of food he anticipated needing--966 lbs worth, good for 350 days at 4,000 calories per day. That would take up about 40% of the net available below-deck storage space in the boat (i.e. not including the "shelf" space on the canvas shelves). So there is plenty of room for other gear.

    Eric
     
  12. philSweet
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    philSweet Senior Member

    The numbers for food storage seem a bit whacky to me. I deleted these comment from an earlier post that was getting too long, but it seems like a good time to mention them. If you talk to the long distance hiking community, or the bike touring community, you will find very different numbers.

    If you take a chemistry-set approach to food, you can get 4000 cal/day down to about 12 ounces/day including balanced nutrition and bombproof packaging. This would get really boring after about 3 months. And every meal needs to be soaked, then prepared for maximum digestibility, then cooked properly, then eaten immediately. And the low bulk can cause troubles over long periods of time. Cubes are often more of a concern for hikers and bikers than weight, and this translates into digestive bulk problems. On a 28' boat, there is no storage volume issue at all, so some very low density foods can be brought along. The minimum amount of fuel needed for cooking is really small. I got about 45 meals per 12oz can of butane cooking on the ground often with little soak time using a primitive stove and uninsulated cookware.

    At 1 pound per day, you get snacks and a bit of ready-to eat food. Jerky can be cured so that it doesn't need to be rehydrated. Although in a boat, just sitting it out for a few hours would soak up a lot of atmospheric moisture, perhaps a box installed in the exhaust hose?. Edible desiccants, anybody:idea:

    At a 20 oz, you've got an allowance for appliances and baking. Some meals don't need to be cooked. Digestibility is down, but the digestive bulk issue is largely solved.

    At 24 oz, you've got tinned meats, canned fruit, honey. When I packed for the Bahamas cruise with absolutely no concern for weight, I ended up just over this.

    Commercially sold individual meals are each packed in a bombproof wrappers. This is a huge waste for the type of adventure planned. No expeditions use this type of packaging as it generates far to much waste and is not very handy in general. (Most food suppliers offer alternate bulk packaging for large group meals, and some offer fully custom packaging.) I generally repack bulk supplies as meals in Ziploc freezer bags. These get bundled by the week into 2 Gallon Ziplocs and labeled. A month's worth then gets sealed in a rubber seabag along with snacks and extras like batteries, chapstick, sunscreen, a book, and a clean shirt. By having access to a week's worth of food at a time, you have some sense of menu choice, at least for the first three days. Doing this for a year's worth of food would basically mean lining the hull with Ziploc "pillow packs", which is a good thing. The hull would need hardpoints for strapping the seabags with webbing. I'm not fond of the canvas shelves idea (or any type of string mesh) because it's too easy to get tangled up in pockets and break fingers. I would want more of a smooth bouncy-house interior, with the ability to jamb a foot or fist into the gaps between bags for a purchase. There are some foods that crush too easily to survive a year in a Ziploc. The best "hard" pack I have found is to take two 1/2 gal milk jugs and cut the tops off and slide the bottoms together. These will survive years of abuse and protect stuff like loaves of bread and dehydrated broccoli. They work much better than plastic popcorn/pretzel barrels and such.
     
  13. philSweet
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    philSweet Senior Member

    And related to the food issue.

    When Jacob is doing a training row, he should adopt the diet a week before he begins, continue it a week after it ends, and monitor calories burned with a standard device. When training for one task such as rowing, the body can become amazingly efficient at it over time, but getting the food budget correct is important. 4000 cals may be a bit low, particularly in cool wet conditions. I planned one trip that I knew was going to be tough at 6000 cals per day for 12 days. At day 8, I sat down and cooked every last scrap of food I had and bailed out 45 miles down a woods road. It was tougher than I though with a lot of 50 - 80 mph winds on the ridgelines. But I put up a first winter passage over the part I completed. As a hazard tree cutter for the USFS, I had to snowshoe into high altitude campgrounds prior to opening and spend the day felling trees. I did this about 14 hours a day for 40 straight days in Colorado and was running about 9000 calories per day.

    When distance hiking, I was in the habit of marking meals on my maps. I ate when I had gotten to the spot, not based on time of day. This does wonders for ones mileage.;)

    Suggestion: Put a stroke counter on the boat with a nice big display. Use a proxy sensor to count oar strokes or seat slides (I'd use a count down system). You get to eat something every 1800 strokes. Mind games are really important to this kind of task. You can end up in a funk for a week if your diet is off and you don't have a way to motivate yourself. Wall clock time doesn't have a lot of relevance after a couple weeks of this sort of thing.
     
  14. Eric Sponberg
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    Eric Sponberg Senior Member

    Thank you Phil for your observations which give handy data about food consumption and energy requirements. Jacob was here in my office yesterday on a brief trip to Florida, and I know he has been looking in on this thread. I'll forward a link to him of your comments for his consideration.

    Eric
     

  15. trefall
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    trefall New Member

    Phil knows way more about this stuff than I care to but has Jacob looked into the nutritional research that couple used when rowing the Pacific using a high fat diet? From what I vaguely recall they broke the record and were better off physically afterward. I also recall them commenting in some video that their meal weight was much lighter than normal high carb long-distance diets. Just a thought. With my memory I don't remember the names of anyone involved but I think the guy was some Finnish adventure type. Somewhat famous I guess.
     
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