Small Self-bailing row/sail design

Discussion in 'Boat Design' started by Russ Kaiser, Aug 20, 2012.

  1. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    I am seeking plan recommendations for a dingy that will be primary used for rowing but would have the option to sail.

    I have thought about doing a bit more rowing for exercise and there is a small lake in a municipal park near my workplace that for a few dollars a season will allow you to tie up a small boat. Every time I have checked they have had available slips.

    Since this boat will be left uncovered, I am looking for something that will shed storm water, weather well, and be relatively inexpensive to build (it may get stolen). On a typical morning, I would like to carry my oars and seat down to the boat and be out on the water in a couple of minutes. Occasionally on a weekend when the wind is brisk, I might want to carry a simply sailing rig and go out on the lake with my children. So I guess I am looking at a feet-dry displacement of 550 lbs. or so. In the compromise that is any boat design, I want better rowing performance than anything else.

    Is there any design out there that fits the bill?

    Russ
     
  2. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,481
    Likes: 61, Points: 48, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    Only "self bailing" row boats I've seen are Row-Cats and those

    row-across-the-ocean boats, and lifeguard boats.

    Take dory plans and make one of these.....

    http://fabianlewkowicz.photoshelter.com/image/I0000tqsyqy9IIAM

    with big hatches to raise the floor and huge storage under neath.

    I don't think it would be hard to put a lip around the hatch openings and have the hatches seal pretty tight, and any water draining out the side holes.

    With a decent lip I think you could open a hatch and put your feet in a lower position if desired and not get much water, if any, into that tub, and it would only be one small tub(less than 20% of whole raised deck.

    Might not be 100% dry when "sailing on its ear" and taking a little water in through the drain holes, but should be epic surf boat.

    You might rig some flaps or something for the big holes, so that "green water" would tend to be kept out in choppy waves, but the boat would still self bail and drain rain water.

    I feel chance of surf dory being stolen are fairly low.
     
  3. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 139, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    Seems to me you are opposite ends of requirements. A boat that rows well will be a very clumsy and slow sailor, will not perform up wind well and will be difficult to control in anything other than a down wind sail.

    Either get a row boat and enjoy it, or get a small sail boat and live with the inefficient rowing. You can not have both a reasonable sailor and a good row boat.

    You can compromise the design and it does not do either well, but is usable in either mode. Not sure what you would do with a dagger board and rudder on a row boat, but you need both to sail at all. A beamy boat does not row well, but is more stable and has more room for passangers, and will sail well, but you will not be happy with the way it rows. If the purpose of the rowing to get exersize, than does rowing performace matter? You will either have to row a sail boat hull, or forgo the ablity to sail except down wind.

    good luck
     
  4. messabout
    Joined: Jan 2006
    Posts: 2,999
    Likes: 202, Points: 63, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Looking for prospective plans.......assume you will build the boat.
    needs to be cheap.......................might be stolen
    Primary aim is ........................... rowing. Row for exercise or to go fast?
    Secondary aim........................... sailing
    You will carry the seat..................does this imply sliding seat type?
    feet dry 550 pounds.....................does this include the boat and gear?
    Self bailing..................................it will need a double bottom and scuppers above the WL

    That is a combination that, as usual, is difficult to achieve. Impossible? probably not, I mean we have a vehicle on mars right now but it did cost quite a lot and is not likely to be stolen.

    A good rowing boat needs to be long, light weight, and very skinny, thus not ideal for sailing unless you are OK with acrobatics and sometimes swimming. Therefore a compromise is needed. Not too skinny, not too wide, conservative sail area and height.

    A self bailing boat will require extra material, work, cost. Also a double bottomed boat will tend to float upside down if not appropriately ballasted. Not a deadly problem if you are athletic, swim well, and have fairly good boating skills. Best abandon the self bailing requirement. Use some sort of rain cover.

    For a reasonable compromise for all this....I'm thinking of a slender flat bottomed skiff about 16 feet long. Steve Redmonds Whisp comes to mind. Whisp claims a rowing speed of one mile in 12 minutes. It is a lovely little boat that I would steal if I had a dead of night opportunity. It will sail but its primary aim is for rowing.

    Similar but less elegant skiff plans are easily and cheaply available. Check out the Duckworks web site for examples. Wooden Boat magazine, a while back, did a series for building hardware store/Lowes/Home Depot style skiffs. Cheap, easy, they are not bad. Check their website.

    One option that has occurred to me is to find a derelict Sunfish, rig up some oar locks. It is four feet wide and 14 feet long more or less, weighs about 125 pounds. Competitive Sunfish sailors replace their boats fairly often because they become less competitive with age and vigorous use. The Sunfish is fibreglass, sails very well, has completely enclosed decks with only a small footwell. It is not hard to recover after a capsize. These little boats are all over the place at garage sales and back yards. A few hundred bucks will get you a useable one. Not the best for rowing but it satisfies several of the other requirements. If you find one that has a faded oxidized skin, all the better. It is then not as attractive for thieves.
     
  5. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Messabout,

    Yes, seeking plans so I will be the builder. Not a dreamer, I am finishing a boat right now, everything done but the paint.

    550 lbs. would not include the boat, so displacement was a poor choice of words. So let's say feet dry carrying 550 lbs, two adults and gear or an adult and two young children.

    I'm willing to make it wider than optimum for sailing stability and if that makes it harder to row, I will get a bit more exercise. I don't want to try to sail a canoe, and I don't want to row a coal barge.

    I pictured an open transom design with a raised floor, low floatation boxes which become natural seats when sailing run along both sides. Rails on the inside wall of the boxes could support a central and removable sliding seat assembly for rowing.

    Less than 15 but more than 12 ft. LOA a max beam somewhere around 54 inches so I don't need outriggers for the oars.

    Since it will sit in the water constantly, it will be filled with pour foam and be completely fiberglassed. I would like to keep the material budget for the hull alone under 600 dollars and keep it as light as possible.

    Yes it's a complete compromise, but it's a boat to be dedicated to a single small body of fresh water that would give me the option to row without having to launch each time.

    Russ
     
  6. messabout
    Joined: Jan 2006
    Posts: 2,999
    Likes: 202, Points: 63, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    It appears that you have gotten near a suitable formula. I'd make the boat as long as you can tolerate, so 15 ft. LOA. Fifty four inch sheer width will work fine for the oars, maybe seven or seven and a half footers.

    Rowing with the mast up is not fun. So I reckon you'd want a simple free standing rig that you could easily transport. In order to get enough sail in a short rig you'll probably want to consider a lug or a sprit rig. To push the boat and a payload of 500 plus pounds well enough to hold your interest, you will want a fair spread of canvas. But there is a practical limit. More compromise is demanded here.

    Poured in place foam is great but it is pesky stuff that does not readily conform to your wishes. The most frequent problem is to try to get it to form a flat top for the floor. This will take some trimming, grinding, and perhaps some carefully selected profanity. The job is doable. I have done it for a 17 footer but it was a lot of work.

    Take a look at the Goat Island Skiff. You can google it and see what a nifty skiff this is. There are a lot of them in service. They are pretty quick under sail, stable, and would row decently but not spectacularly. Easy build too. With a little tweaking you could modify it to include the foamed floor and transom flaps.

    Transom flaps: Hinged at the top, gasketed, doors at the bottom of the transom, often seen on competitive dinghys. Flaps (doors) are often made of lexan so that you can see the water coming off the bottom at the transom. Can be held in closed position with a shock cord and small cleat. Make them 6 or 8 inches tall and 8 or 10 inches wide. These are a real convenience when washing the inside of the boat too.

    Keep in touch so that we can follow your progress. What kind of boat are you presently building? Post pix if you have them.

    I expect that you will use up all of the $600 for the hull and maybe some more. With good planning and careful shopping it could be done I suppose.
     
  7. messabout
    Joined: Jan 2006
    Posts: 2,999
    Likes: 202, Points: 63, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Russ; I just looked at the sailing section and saw some pix that might interest you. Click sailing, scroll to post; Would like to read an old post. Picture of double bottom using cheap foam.
     
  8. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Glorified Jon Boat

    OK, so the project continues, at least the looking, head scratching, and fiddle-farting aspects. I have looked at several plans and considered trying to adapt them to have self draining cockpits. I haven't given up, but I have eliminated a lot of boats.

    One thing that hit me today was that I could build a narrow cat with an open framed seat platform that would make a decent single person rowing hull - it would throw all the other criteria out the window however. It could be fairly light and the hulls could be designed to shed water so it could be left out in the elements.

    Since I was having trouble finding anything to adapt, I drew up one design with air boxes that was sharp prowed. It had a sloping floor elevated above the waterline sporting an open transom. It looked like a skinny 15 foot sailboat. I drew it as a solid and then started slicing it to get an idea of how I would frame it. I don't know if you guys work or think that way, but that's how I started this particular drawing. The short story is it was going to be a bear to frame so I scrapped it.

    So then I took up a different tack, and started building a virtual frame and then skinning it. I keyed everything off of the floor and sides of the well which I figured I would make from 1/2 plywood for strength plus I already have a stack of it. I have developed that plan a bit more and damn-it if it doesn't look like a fairly ugly Jon boat. It is also going to be HEAVY!

    LOA 14.4 feet
    Max Beam - 56 inches
    Feet Dry (well trimmed) Displacement ~ 800 lbs.

    Since I have gone to all the trouble though, I will throw up some photos for public criticism - be gentle. I figure the sheet stock alone is going to weigh 210 lbs. This is based on the square footage Rhino gives me for the parts. There are plenty of places to hole the red colored ladder frames under the floor level, but I don't see that reducing the weight more than two or three pounds.

    Add onto the sheet weight some incidental framing, mast support, dagger-board and trunk, glass, glue and epoxy, I don't see the boat ending up much less than 380 lbs. I have tentatively christened the design, Chunky Monkey.


    Below is the top view - The "well" is 32 inches wide and 10-2/3 feet long.
    [​IMG]


    Here is the bottom, it's flat with lots of rocker and then the air boxes are tacked onto each side to give it a more rounded and tapered profile. I am sure it will provide plenty of rowing exercise :p

    [​IMG]

    Here are a couple pictures of just the frame elements, obviously there will be some cross framing to hold the bottom off the well floor and to support the air boxes. Most of that can be light.

    [​IMG]

    [​IMG]

    Here is a profile of the center section showing the shape of the flat section and the position of the elevated floor.

    [​IMG]
     
  9. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Very interesting

    I could see this making a light-weight boat for a single person that would row and sail well, but I don't think this type of construction would scale up to the size boat I was looking for. The technique is definitely something to consider.
     
  10. messabout
    Joined: Jan 2006
    Posts: 2,999
    Likes: 202, Points: 63, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    OK that'll float. True you have drawn a jon boat. I suggest that you can call it Battlestar Gallactica. a 14 foot boat built of half inch ply is more than overkill, it is absurd unless you intend it for demolition derbies. Have you made it barge like to assure that no one will be strong enough to steal it?

    Sell the 1/2' ply and get some 1/4 and 3/8. Even though you already have the too thick and too heavy ply, it will not be a good bargain. You are building a nice little boat not a dreadnaught,

    There is some merit in the large beveled chines that you have drawn. They tend to diminish wetted surface for a given displacement if you get the proportions right. Thats the positive feedback that I can muster at this time.

    suggestions...Pinch the ends of the boat together in plan view. Let the fore and aft transoms be about 30 inches wide more or less. You can keep the mid section width if you like. Be sure that the bottom at the aft transom is slighty above the WL when the boat is fully loaded. Consider avoiding foam. It will become problematic as it ages it will also be a ***** to install satisfactorily. Frame the underfloor and epoxy saturate it as in West system. Put limber holes in the framing and arrange for some ventilation hatches in the floor. Why bother with the side tanks? The double bottom will provide more than sufficient flotation. The side tanks will only add weight, complication, and produce another pair of spaces that will need ventilation.

    With these minor mods you will have a pretty fair scow that will sail better than the jon boat thing. It'll row better too. And it will be much lighter and more pleasing to use.

    P.S. Do not be insulted by my critique, there is nothing personal here. You asked for comments did you not?
     
  11. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Look at a Pea Pod or a multi chine variant of the same. It'll row well, can carry a load, can sail and is light weight.

    On the other side of the coin would be a skinny skiff and there are quite a few of these to choose from. The GIS is primarily a sailor, but can row fairly well. Bolger's light dory is an option, though without a sail plan, rows quite well. I would suspect a small rig could be employed on one.

    Self designing a boat to this SOR would be exceedingly difficult for the novice. The boat above wouldn't row well, though shows considerable thought. It would do better as a sailor, but again has issues, in this regard as well.

    The self bailing requirement of the SOR isn't practical in a boat of this size. It tends to place the CG so high as to make the boat unstable, or at the very least uncomfortable. By this I mean you're "on" the boat rather than "in" it. This can be quite uncomfortable for most and makes moving around difficult. A bit like walking around on a surf board. What is the logic behind this requirement? Small non-self bailing boats, have been used in open water for many generations, with great success. Buoyancy chambers or built in floatation can address swamping issues easily and a small bilge can offer a place for boarding water to reside, before it gets pumped over the side. A reasonable sole height, for a self draining cockpits is 6" above the LWL, more if you're heading into deep and/or rough water. Frankly, on a boat of this length, you just don't have the freeboard to offer this particular aspect or the SOR.

    Finally, a boat of this general size doesn't need to be more then 200 pounds, full up. Your weight suggests she's way over the top in material dimensions. Small, light craft, intended to meet as conflicted a set of requirements as desired here, isn't easy. I'm not sure why your structure is so heavy, but it could easy be half the weight of what you've mentioned, with more than adequate stiffness and strength for the tasks you have planned. This isn't a personal set of insults, but just to highlight the difficulties in small craft design, that all designers face.
     
  12. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Nothing ventured, nothing built

    Messabout and PAR, thank you for your input. Luckily my investment in the design is just a couple of hours I would have wasted watching TV. I am not married to this design but let me however re-explain my SOR.

    I live approximately 7 miles from the place that I work and 2 miles from work is Salem Lake - a tiny body of water (7 mile perimeter) that like many in our state that are used as a drinking water supply doesn't allow swimming, skiing, jet craft, and large motors. Right now this lake is re-filling after major damn renovations and probably won't be open until next spring. It is a perfect lake for rowing.

    I want to leave a boat there to row a few days a week either before or after work depending on the season. I used to row for exercise when I lived in another state and I miss it. For this plan to work for me on work days, it is important that I maximize the rowing time and minimize the fiddling time.

    I don't want to mess with a cover, since that will take a few extra minutes to put on and take off and will probably require bows and snaps or at least securing with a few ropes. I also don't want to have to bail it every time I go down and it has rained. It is not unusual to get a couple of inches of water here from a single could burst. This is where the self-bailing requirement comes from.

    Since I will be by myself and on many mornings there won't be a lot of traffic on the lake, I would like to insure some stability, this is one reason for the boxiness of the design. For me the most dangerous aspect of small boating is getting my butt into the boat. I could build some racy little car-top-able design, but if I launched it 100 times a year, I would probably end up in the lake 5 times a year and I might crack my skull on a dock during one of those falls.

    Since I will already have a boat berthed at the lake, it would be "nice" if it could pull some moderate double duty. The other reason I made the boat so square was for the added stability of sailing with a couple of my children or my wife. Here the air-boxes not only add width, but provide a nice place to park the rear if the winds comply, Of course, in light winds I could have a couple of movable thwarts that rest across the well that would allow two people to sit inside the well in tandem.

    As for the pour foam, my thought was that once the entire boat was framed and sealed except for the deck, I could pour it in via the air boxes. With enough limber and lightening holes connecting the air boxes to the bottom, and by pouring in many locations, I though I would stand a decent chance of filling the entire bottom cavity. I also considered that I could leave the top of the air boxes unfilled for a bit of secure storage.

    So now you know why the design so far has been such a wacky compromise. All of this said, I am not invested in this design and I am not dead set on using any of my 1/2 plywood "stash".

    I re-read the original responses to this post and Squidly-Diddly mentioned a cat. I have come to the realization that a cat might serve the rowing aspect well, so I am inclined to say now, let's build a single purpose boat for rowing that is easy to board, has a lot of stability, rows very well, and doesn't collect water when docked. Something like two canoes with a self draining deck with their outboard edges 54 inches apart.
     
  13. KJL38
    Joined: Jun 2008
    Posts: 88
    Likes: 9, Points: 8, Legacy Rep: 75
    Location: Tasmania

    KJL38 Junior Member

  14. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Not opposed

    Thanks for the heads up.

    If I decide to go the cat route (I am still messing around with a mono-hull plan right now) this might be something I would consider. Since this ad says that it needs "Fiberglass" work, it may be a pig in a poke. There might be 100 dollars worth of aluminum to recycle there however.

    That "project" definitely looks like something that set in the water for extended periods whereas most most small cats like the donor normally get hulled up the beach above the high tide line between outings. If it's pretty old and polyester based, it may be total trash.

    Also, since I am talking about putting this on a calm, freshwater lake, I might be able to build lighter hulls than this little cat is equipped with plus longer hulls, 15 feet or so would row much better. In fact, if I was going to build something stable to row with two hulls pairing something that looks like two rowing shells together would be a good starting point.

    Russ
     

  15. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 0, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Dumb Multi-hull Question?

    I am still looking at plans and boats and noodling with a mono-hull design specifically for rowing. I am also looking at some multi hull rowing designs that are commercially available and thinking about going that route.

    This brings up a question I have about multi-hulls. They say there's no such thing as a stupid question, but in the back of my mind I'm thinking some of you will think this gets close.

    1. For a stable cat rowing platform would it be more efficient to design the best mono-hull you can and then split it down the middle, or to design two hulls with a traditional symmetrical shape?

    2. If by chance splitting a mono-hull would be the best route to go, would it matter if the hulls were situated as shown in the picture? This relationship would seem to maximize stability by putting the most buoyancy at the extreme edge of the platform.

    [​IMG]
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.