I need to build a boat in two months for a charity race!

Discussion in 'Boat Design' started by dmax, May 24, 2010.

  1. dmax
    Joined: May 2010
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: usa

    dmax New Member

    My company entered a charity boat race down the river in my city for the United Way. I want to WIN this! The race is about 4miles long. I need a boat design that will carry 4-5 people. It must be man powered and totally home made. We have until July 31st to finish. I'm thinking about some sort of pedal or hand powered side wheel paddleboat with 30gal plastic drums for pontoons. Remember we do not have much engineering experience! Any help is much appreciated.
     
  2. Guest625101138

    Guest625101138 Previous Member

    Is there any length constraint.

    The fastest boat for 4 people will have the length of rowing-4 or a K4 kayak. Somewhere between 10 to 12 metres.

    You can add stabilisers that prevent it from rolling.

    Paddling is the simplest means of propelling it.

    The main hull and stabilisers can be made very simply using outdoor ply in a weekend.

    Rick W
     
  3. messabout
    Joined: Jan 2006
    Posts: 3,127
    Likes: 294, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Rick is an international authority on such things.We must give him his due. However, I suspect that you must build cheap and dirty as well as PDQ. Let us explore possibilities.......... First thing is that oars are more practical and efficient than any kind of paddlewheel or other mechanical gadgetry. 30 gallon drums are out. Don't even consider that kind of stuff if you want to go fast. Lets build a really simple boat that can beat the competitors unless they are extraordinarily shrewd.

    Your boat should be long and narrow. Lets say 23 feet long and 36 inches wide. It will be ugly but efficient. It is a squarish box with an open top. It has sides that are 17 inches high. The ends are pinched together, both ends. Now you have a 23 foot long streamlined box. The bottom will have the shape of a rocking chair. Pull the front and back of the bottom up 4 inches. Is it any wonder that boat guys call this design principal "rocker"?

    Choose a crew that is athletic and does not average more than 175 pounds each. Dont eliminate the girls for crew selection. Some of em are tough as nails. The object is to keep the total weight of the boat and crew as light as is possible consistant with enough endurance to get through the 4 mile course. Figure on doing the course in a little less than an hour. If you have a really strong and light crew you might do it in 45 minutes. Rowing can be a strenuous exercise when you are pushing hard. Turning a paddle wheel is way more arduous.

    If you use something awful like 30 gallon drums you can figure on two hours or so for completing the course. Your fast boat will get to the finish line and the crew can consume a few beers before the others are even in sight.

    When you build this boat it does not need to be pretty. You need to spend some time making the exterior smooth.and slick. You can do that with sweat, sandpaper and paint. Slick will matter in a physical endurance race. Never mind the interior. You can use either a single banked or double banked oar system. Double banked is when each crew mans only a single oar, in which case you will have only four oars instead of eight. I would opt for eight oars if the the crew has reasonable coordination. Build the boat, go practice, smoke the competitors.
     
    1 person likes this.
  4. Guest625101138

    Guest625101138 Previous Member

    I was thinking anything under 30 minutes would be a reasonable result with 4 or 5 untrained paddlers. A trained crew should get under 25 minutes to cover 4 statute miles.

    Rick W
     
  5. dmax
    Joined: May 2010
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: usa

    dmax New Member

    Thank you guys for the info! Where can I get good detailed plans to build a cheap, fast rowboat out of plywood?
     
  6. Guest625101138

    Guest625101138 Previous Member

    It does not have to be fancy to be fast. It needs to be long, slender and stable.

    The attached gives you an idea of the ideal for a total displacement around 400kg. It should weigh about 40kg so you can use a total of 360kg of good meat to propel it.

    The main hull is 11m long and about 400mm wide by 300mm high. It can be made from 4-ply. You should place bulkheads about every meter within the hull.

    The stabilisers are 4m x 100mm wide x 150mm high. These can be made from 3-ply. These need 3 bulkheads. One in the middle and the others where the beams connect.

    The orange box seats can be made from 4-ply. The red stabilisers beams can be 3-ply.

    You need about 120m of 12mm (or a bit bigger) square timber mould for all the corners to join the sheets.

    You may want to fiddle with the height of the seats and it will be easier to paddle if you have foot straps to lock the feet into.

    You need about 500ml of polyurethane glue for all the seams and about 200 off 12mm long countersunk brass screws. (The brand of glue I use is Vise)

    You need a few sheets of ply.

    You need some sand paper and some paint to seal the wood.

    The shape is not super critical as long as the length and beam are as shown. It will draft 150mm if built as drawn when total weight is 400kg.

    To make the sides you cut strips of ply 300mm wide and join them with a splice plate 270mm long by 50mm wide. Cut the fore and aft of the side sheets to form the hull rocker - again not critical. Then glue and screw the moulding to the top and bottom edge of each side.

    Cut ply for the top and bottom, splice to continuous lengths and than glue and screw the top in place. Cut bulkheads with corner notches for the moulding. Glue and screw moulding to the edges of each bulkhead. Glue and screw bulkheads in place. After the bulkheads are firm, glue and screw the botom sheet in place. You need to think about placement of bulkheads so they do not foul the splice plates.

    Similar processs for other bits. It helps if you have access to good tools.

    It will move easier than a K4 kayak but not quite as fast as a 4 man rowing shell.

    You need 4 paddles. If you have novice paddlers then a single bladed canoe paddle will be faster to learn than a double bladed kayak paddle.

    If the length presents a problem for transport then build it in 3 bits with a 6 to 7m long central section and two end sections joined about where the fore and seats are located.

    Make a cardboard model of the bits first to see what it looks like. Post a photo when you have made the model.

    You can use heavier ply if you want but it will make the boat a bit heavier. The fully enclosed shape has good inherent strength and is very simple. It has a myriad of buoyancy chambers and made from buoyant material so will be unsinkable.

    Rick
     

    Attached Files:

  7. Tiny Turnip
    Joined: Mar 2008
    Posts: 748
    Likes: 180, Points: 43, Legacy Rep: 743
    Location: Huddersfield, UK

    Tiny Turnip Senior Member

  8. kerosene
    Joined: Jul 2006
    Posts: 1,098
    Likes: 91, Points: 48, Legacy Rep: 358
    Location: finland

    kerosene Senior Member

    If you build a boat like Rick described you will win. I am almost certain about that unless we get another thread from your competitor.

    Make it crude looking so others don't feel like you cheated :)

    do you have to make paddles/oars yourself too?

    Now start building it and post your paint/glue/joint questions to the forum. And lots of pics.
     
  9. Submarine Tom

    Submarine Tom Previous Member

    Is welding allowed? I'm thinking 45 gallon drums cut in half, vertically, and welded into a hull.

    A couple of pointy ends and your set. Get your more competent rowers in first to steady the boat.

    Get it done early so you can have lots of training exercises and trouble shooting.

    I suspect most will DNF (did not finish) so speed may not be your primary objective.

    Good luck! Don't forget your life jackets.

    -Tom
     
  10. kerosene
    Joined: Jul 2006
    Posts: 1,098
    Likes: 91, Points: 48, Legacy Rep: 358
    Location: finland

    kerosene Senior Member

    plywood boat will be multitude faster than very heavy steel hulled stubby thing - round cross section hull is not particularly stable either. And if it floods you are swimming home and have your barrels in the bottom of the river.

    long, narrow and light (probably in that order) per Rick's comments are the keys to fast boat.
     
  11. Submarine Tom

    Submarine Tom Previous Member

    kerosene,

    Five sections with pointy ends (total seven sections) is long and narrow.

    Low seating is stable, floataion provides positive buoyancy (a given).

    Welding's pretty quick, weight and speed may not be as important as durability here.

    Please, lets try and be constructive here, we're trying to build something not tear it apart.

    It's called collaborating also known as brain storming.

    I didn't say anything to indicate I didn't support Rick's ideas or yours for that matter.

    Give your head a shake.

    -Tom
     
  12. kerosene
    Joined: Jul 2006
    Posts: 1,098
    Likes: 91, Points: 48, Legacy Rep: 358
    Location: finland

    kerosene Senior Member

    I shook my head. Sorry if I my post came off as negative. I just think that the plywood plan is easier to accomplish and you are more likely to end up with a winner and reasonably portable boat.
     
  13. Submarine Tom

    Submarine Tom Previous Member

    Lol...

    You may be right.

    Apology accepted.

    -Tom
     
  14. apex1

    apex1 Guest

    But he was right on the hull shape too!

    And I like to concur that Ricks approach will be a most sensible one. (I know that was almost unbelievable that I agree with Rick)
     

  15. messabout
    Joined: Jan 2006
    Posts: 3,127
    Likes: 294, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    The boat that Rick has given to you will be very swift. Much faster than the one I suggested. The big difference is that Ricks boat is 16 inches wide 36 feet long, and will need some stabilizers such as those that he has shown. The one I dreamed up is really just a crude, somewhat elongated, canoe. It would not need stabilizer floats. The reason for the 23 foot is that it fits ply wood sizes and gives some consideration to costs. Longer would be better...maybe 4 sheets of ply instead of three. (I was thinking in terms of a poor mans Dragon boat.)

    To be sure Ricks boat could humiliate the competitors, that thing will go. My boat will be pretty quick but not in the same speed category as the Willoughby splinter. If I were to do such an event, I'd opt for the splinter. But I have lots of boat building experience and would not be daunted by a really long boat. You need not be hesitant either. After all it is only a box that floats. The splinter just happens to be a very diabolically and craftily contrived box.

    The course that you are navigate may play into the choice of boat that you build. Please describe it in terms of whether it is a straight line run or a course with numerous turns. What water conditions would you expect? Lot of waves and wakes or relatively calm? Is there a signifigant current flow? etc....

    Stay in touch, we are interested in your progress.
     
Loading...
Similar Threads
  1. somaero
    Replies:
    33
    Views:
    4,022
  2. DrummerVT
    Replies:
    7
    Views:
    1,496
  3. old pine
    Replies:
    23
    Views:
    3,729
  4. G_On_A_Boat
    Replies:
    21
    Views:
    2,895
  5. thedutchtouch
    Replies:
    6
    Views:
    3,398
  6. Missionary Dave
    Replies:
    20
    Views:
    9,235
  7. wvwelder
    Replies:
    2
    Views:
    1,289
  8. Sceptre
    Replies:
    7
    Views:
    33,883
  9. justinfitz1
    Replies:
    12
    Views:
    2,002
  10. Salmoneyes
    Replies:
    10
    Views:
    1,094
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.