Page 3 of 5 FirstFirst 12345 LastLast
Results 121 to 180 of 255

Thread: Design and build proper looking canoe?

  1. #121
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Another stupid question...

    Why are some boats V bottomed instead of flat?

    Er...Dynamic stability...?

    If you cut a paddle through the water, it sort of hardens up the water on both sides, making pulling it at the same time very hard.

    The same thing happens when a boat slides through the water. The moved water hardens, and although the boat slides through it, it sort of resists the boat dependant upon it hull shape.

    If the boat has a flat bottom, it pushes the water downwards and the pressure sort of builds up under the middle of the hull - much the same way as the sugar formed a round shape in front of the square fronted raft. This does nothing to stop the boat rocking from side to side....



    If the bottom of the boat is round, it pushes most of the water downwards, and a little sideways, hardening the water to the sides as well as the bottom. This side pressure helps keep the boat stable..



    The third shape is the V bottomed hull. This pushes all the water out to the sides. The downward force of gravity works against the water pushing sideways and up and resists any rocking forces. You see this with powerboats that will rock from end to end as they power over waves, but little or no sideways rocking. This makes the moving hull as stable as a much wider stationary hull...



    Canoes usually start V bottomed, pushing the water sideways, before flattening out and pushing the water downwards in the middle part of its length. This supplies stability and a better cut through the water with a shallow draft or depth, which is very useful in shallow water.



    Some of the angled side is usually in the displacement area in canoes to give more dynamic stability.

  2. #122
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Struggled with the pics in the last post. Not sure Ive got them clear enough.

    Not even sure Ive got that bit of theory completely right either.

    Is it right? Is it near enough? Are the pics good enough to show this widening of the canoes footprint as it moves?

  3. #123

    Default

    By Now you should have some idea of what shape your looking for.
    The best shape to work well still seems to be Long Canoe shape with chines.

  4. #124
    Join Date
    May 2011
    Location
    Lincs
    Posts
    735

    Default

    Stonking thread!!! keep up the good work
    --
    Andy

  5. #125
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Thank you Sonar

    Thank you Andy Lincs

  6. #126
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Next stupid question...

    If having a wide gentle curve from back to front helps the canoe go faster, why are the ends often very narrow?

    Simple answer - Tracking.

    With a row boat, you have a couple of oars and shove them both in the water at the same time and pull them. The row boat ends up getting propelled between the two flat surfaces of the oars in the water in a pretty straight line.

    With a canoe, you often have only one paddle, oar and pull it on just one side, or a double ended paddle, which you pull on one side and then on the other. Either way, the pull on just one side tries to turn the boat. Having two sharp ends in the water acts as skegs and keeps the boat tracking fairly straight.

    Wind is also a factor with canoes. The wind pushes one end or the other away from the wind. If you have the sharp ends in the water, the boat still tracks reasonably straight. Sometimes, if the canoe will not track straight in a side wind, the paddler will stop and put a large rock in one end of the canoe to get the end in the water as this makes it track.

    Another stupid question...

    Can you have too much end in the water?

    Short answer - Yes.

    If tracks too straight, you can have a serious problem trying to turn the boat. Not too much of a problem on a large open body of water, but can be a serious pain when you need to turn fast in white water when you are heading for a large rock.

    Three ways to fix this;

    More rocker,

    Round the undersides of the ends, so the water can flow under it allowing the boat to turn.

    Roll a wide canoe on its side so that the keel comes out of the water. This shortens its waterline length and makes the boat turn rapidly. If you are going to try this, you really need to design the boat to suit this style of paddling.

  7. #127
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    When you paddle the canoe in a straight line, it pushes the water out of the way to both sides.

    This push on the sides is balanced in one side gets the same push as the other side.

    The water gets pulled into the trough behind the boat from both sides. This uses power too, but is also balanced from side to side.

    When you turn, one side stops pushing water away, and the other side pushes twice as much.

    Behind the canoe, one side has to pull the water back, and can even end up pulling from the wrong side as its closer.

    As you turn, one side has to push the water and pull it back, while the other side does nothing. It takes more power to overcome the waters efforts to keep the boat going straight.

    This drawing is exadurated, but gives some idea of what happens if the water does not pass under the boat...


  8. #128
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Stupid Question time...

    How can I check that all that er....stuff is right.

    Lol.

    Easily. Easily as talking to yourself.

    You will need a puddle or sink, a couple of desert bowls, a few elastic bands, a long pencil and somme duct tape, or pvc tape if you havent got any.

    Oh, and a couple of teaspoons.

    Sombody must have been very drunk when they designed the coracle.

    Its a completely round boat.

    It hasnt got pointy ends and so it spins round in circles - unless you are a genius and have learned how to paddle one.

    Gotta go.

    We will fix a coracle later so it tracks straight.

    This will let you test that this er... stuff is right.

  9. #129
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Just waiting for the tide to come in on Lake Sink....



    The Coracle - complete with paddle...



    If the hull of a boat does not force the water out of the way when it turns, it can turn fast.

    The less resistance, the faster it turns.

    So, if I put it in the water and spin it, it will settle to a speed fixed by its resistance.

    The paddle will show us its spin as its pretty uniform...

    Last edited by No Idea; 13th-March-2012 at 08:50 PM.

  10. #130
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    If you give it some resistance - like an upright end, it will not be able to spin so fast as it must then push water out of its way like the canoe ends do.

    You will need a piece of tape, a pencil and an elastic band...



    Stick the pencil on the tape in the middle, but not quite square...



    Fold the tape over like a flag...



    Get your bowl and pull the elastic bands over the top and push the pencil through the ends under it...



    Ready to be launched again...



    We are looking at the speed they turn at - if I can manage it without spinning them into the side of the sink....


  11. #131
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    The modified one really doesnt want to spin any more.

    Going to try it now with just the pencil...



    Again, you can easily see just how much difference this amount of resistance makes....



    On a 13 ft+ canoe, it will make considerably more.

  12. #132
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Dont take my word for this.

    Get hold of a couple of bowls, elastic bands, pencils and some tape and try it yourself.

    The more you try this stuff, and get to actually understand it, rather than believing its probably correct in theory, the easier it will be to make the descisions you will need to make to successfully design and build your own craft.

  13. #133
    Join Date
    May 2011
    Location
    Lincs
    Posts
    735

    Default

    excellent. The coracle I am building is rectangular. Coracles come in all different shapes, round, squarish, rectangle and almost triangle.

    I think the general idea of the coracle is not just to get from a to b (because I think you start from a and let the current take you to b and then you carry it back to a) but to be quick and easy to build, and manoeuvrable. When I've seen them in use (on TV/DVD) they seem to just drift with the river flow (as many were holding nets across the river). A keel simply isn't / wasn't necessary.

    ...however, since I'm building one for fun before getting more adventurous with a wood canvas canoe build I may well need to put a keel on it because the rivers near me don't have enough flow to get from a to b and also I don't fancy walking back up stream to get to the car My coracle may well end up being more of a rounded rectangular small canoe

    Keep up the good work, some of us are watching and paying attention!
    --
    Andy

  14. #134
    Join Date
    May 2011
    Location
    Lincs
    Posts
    735

    Default

    .....is there an exam at the end of this?

  15. #135
    Join Date
    Nov 2007
    Location
    cambs
    Posts
    852

    Default

    Quote Originally Posted by andylincs View Post
    excellent. The coracle I am building is rectangular. Coracles come in all different shapes, round, squarish, rectangle and almost triangle.

    I think the general idea of the coracle is not just to get from a to b (because I think you start from a and let the current take you to b and then you carry it back to a) but to be quick and easy to build, and manoeuvrable. When I've seen them in use (on TV/DVD) they seem to just drift with the river flow (as many were holding nets across the river). A keel simply isn't / wasn't necessary.

    ...however, since I'm building one for fun before getting more adventurous with a wood canvas canoe build I may well need to put a keel on it because the rivers near me don't have enough flow to get from a to b and also I don't fancy walking back up stream to get to the car My coracle may well end up being more of a rounded rectangular small canoe

    Keep up the good work, some of us are watching and paying attention!
    Andy
    I presume you know about this website?
    Coracles are good fun ad quickly improve your sculling strokes.
    Each year there are usually a couple paddle the Sudbury to sea tour.

  16. #136
    Join Date
    May 2011
    Location
    Lincs
    Posts
    735

    Default

    Quote Originally Posted by samB View Post
    Andy
    I presume you know about this website?
    Coracles are good fun ad quickly improve your sculling strokes.
    Each year there are usually a couple paddle the Sudbury to sea tour.
    I'm sure they are good fun, and I will find out...as I will make one (I have all the bits now, wood, canvas, enthusiasm, including space). But the real purpose of making one is to find out how, (bending wood etc), and how light it can be made and how durable the canvas turns out to be....a learning process for making a wood canvas canoe...or not. I felt it was a smaller project that I could manage before running head first into a canoe project that turned out to be a disaster.

    It's why I'm enjoying this thread as I want to make a canoe and understand why things are the shape they are rather than just rely on someone else's plans.

    I have no doubt that a coracle will teach me a lot, including how to scull, and how to capsize
    --
    Andy

  17. #137
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Quote Originally Posted by andylincs View Post
    excellent. The coracle I am building is rectangular. Coracles come in all different shapes, round, squarish, rectangle and almost triangle.

    I think the general idea of the coracle is not just to get from a to b (because I think you start from a and let the current take you to b and then you carry it back to a) but to be quick and easy to build, and manoeuvrable. When I've seen them in use (on TV/DVD) they seem to just drift with the river flow (as many were holding nets across the river). A keel simply isn't / wasn't necessary.

    ...however, since I'm building one for fun before getting more adventurous with a wood canvas canoe build I may well need to put a keel on it because the rivers near me don't have enough flow to get from a to b and also I don't fancy walking back up stream to get to the car My coracle may well end up being more of a rounded rectangular small canoe

    Keep up the good work, some of us are watching and paying attention!
    Thank you Andy Lincs

    The bottom of the coracle needs to be designed in exactly the same way as the canoe. They are both displacement hulls and obey the same basic rules. The only real difference is that the coracle is a lot wider and shorter.

    The coracle is more than capable of being propelled against the current. They can even be sailed., although I understand that mastering the technique of tipping it to get the hull to act as a keel is almost impossible. Sometime, Im going to have to build one and try it just for the hell of it lol.

    A coracle can be sculled or paddled with a sort of J stroke and even rowed with no keel. My intention was simply to highlight the effect of a keel, not to suggest that a coracle actually needs one. I cant see you having much problem getting it back upstream - so long as its no flowing fast.

    Im really enjoying writing this thread as its making me actually articulate the stuff I know and sort it into some sort of order. Thats improving my knowledge and understanding too.

  18. #138
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Exam at the end?

    Of course!

    Obviously, you do not have to take the exam.

    If you do, you will be expected to work through designing a canoe to meet a set of exacting requirements, source the materials you need and build the design to a suitable standard ready for the examiner to test, while documenting your progress with photographs.

    The examiner is a bit of an unknown quantity, as we have No Idea how critical he will be, or even how long he will take to evaluate your work. He could possibly take months to reach a result.

    Once completed, hopefully, all candidates, while not under any obligation, would be prepared to share the photos and their thoughts, and the results of the Exam here on this site.

  19. #139
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Hi Sam B

    I like the look of the coracles.

    Sculling is something I havent actually tried as I havent a long enough paddle.

    I think Im going to have to bite the bullet and make some oars and paddles.

  20. #140
    Join Date
    Nov 2007
    Location
    cambs
    Posts
    852

    Default

    Quote Originally Posted by No Idea View Post
    Hi Sam B

    I like the look of the coracles.

    Sculling is something I havent actually tried as I havent a long enough paddle.

    I think Im going to have to bite the bullet and make some oars and paddles.
    Sculling as in moving your canoe sideways - a sculling draw stroke - not sculling as in going far too fast backwards with a pair of oars.
    (Hope I'm not stating the obvious)
    Sam

  21. #141
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Nope. No worries about stating the obvious as I often miss it lol.

    I said paddles and oars as I want to experiment with a few things, but forgot that I hadnt said what I was talking about.

    Sorry

    My biggest brat has rebuilt a Mirror dinghy, which he rows.

    I would like to see if I can row the Osprey.

    I would need some long oars for it, probably 10 or 11 foot long.

    I would also like to see if I could scull it by using one oar in a rowlock mounted on the transom.

    My understanding is that you lay the blade of the oar flat in the water and tilt it so the leading edge pushes water away from the boat as you move the handle sideways. You then rotate the oar a few degrees to get the other edge to the angle needed to push water away on the return. The oar moves the water by slicing through it in a Z pattern.

    I would like to try it with the Osprey first as its big enough I cant tip it over if I mess up.

    I often paddle my canoe with a double ended paddle. I cant stroke as fast as the kids, but Im stronger. Im interested to see whether building a paddle with larger ends would help me keep up with them. I also want one with a longer centre bar as I think putting the blades deeper into the water might stop the vortex behind the blades as they are pulled through the water. It would not be able to pull down air, which, I think would result in more power transfer.

    I also want to have a go at building an otter and a beaver tail paddle. Im curious as to what they are like to slice as all my paddles have a lump from the handle on the back.

    I also think they would make better rudders when Im sailing my canoe, but until Ive tried it, I wont know for sure.

  22. #142
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Tea stirrers...

    I suppose too many people stole teaspoons from the cafe/resturant chains.

    As a result, they now have resorted to supplying little wooden lollypop sticks to stir tea with.

    This includes Mc Donalds, Tescos and Asdas.

    Not Burgar King as they supply rubbish plastic ones.

    Obviously, I wouldnt suggest nicking a fist full of these wooden sticks, or we could end up having to stir tea with a plastic thing thats chained to the counter....

    Anyhow, as you could do with some in about a week or so for some more experiments...

    Each time you go get a cup of tea while SHMBO is shopping for the next few weeks, please keep the wooden stirrer so that we can er....recycle them.

    ...or get her to get some.

    A few dozen would be good.

    I suppose you could just eat a few dozen ice lollies, although those sticks are a bit too thick.

  23. #143
    Join Date
    Nov 2007
    Location
    cambs
    Posts
    852

    Default

    We're not starting mixing epoxy already are we? - I thought that's what those sticks were for!
    (.....and then there's the free pencils you get in Ikea........)
    Sam

  24. #144
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Lol no.

    We will be working out what wood is and how to get it to do what we want it to do.

    Free pencils? Havent been to Ikea.

    Looks like Ive some education to get lol.

  25. #145
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    We need to look at heeling a canoe.

    If your boat sits in the water, level from side to side, as it moves forward, it will push an equal amount of water away from each side.

    However, if you move across to one side, the boat tips.

    As the boat tips, one side comes up out of the water, leaving a straighter waterline, and the other side gets more rounded as more of the side in the middle goes into the water....



    As one side of the boat gets straighter, and the other curves more, only one side pushes water away, so the boat turns.

  26. #146
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    If you lean a bike to the left, it turns left.

    If you lean a boat to the left, it turns right.

    If you are running with wind on the side of a canoe, making manageable waves, you can tip the boat away from the windand use the hull form to help counter the boats natural tendancy to turn downwind.

    Also heeling it away from the wind increases the amount of the side out of the water on the windward wave side.

    This technique is likely to end up with the boat upside down the first few times you try it, so make sure you perfect it in the shallows - or on capsize drill day lol.

  27. #147
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Heeling some more can lift the ends of the keel out of the water.

    This effectively shortens the waterline length making the boat much easier to turn in its own length.

    However....

    If the bottom panel is flat, rather than V shaped towards the ends of the boat, its possible to get the front of the panel in the water in front of the keel, which can make the boat turn sharply in the direction the boat is heeled.

    When you design your boat, you will need to look at this and decide if you want the boat to turn this way or just turn the other way progressively.

    The control is the amount of twist you put in the ends of the bottom panel

  28. #148
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    This is the last animated pic, with the bigger heel at the end.

    Not sure the angle is exactly right, as Ive not managed to see the waterline - other than when I managed to run myself over one day, but then I wasnt heeled.


  29. #149
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    So.....

    Its time to have a look at what we have covered.

    A boat can be pretty much any shape you like, but as far as cutting through water, some are better than others.

    A boat has a bottom to stop ours getting wet and to stop our stuff falling out....




    Pointing the ends makes clear water from its way more efficiently...



    Lengthening it helps to point it....



    Making the bottom narrower makes it more efficient...



    Lifting the ends to give it rocker smooths the waterflow under the hull, making it more streamlined...



    Cutting the ends and creating a V shape while leaving the middle flat helps the boat track in side winds and one sided paddling and helps the hull resist reversing its heel steering as heeling is increased...



    One or more angled sides can be added one above the other to widen the hull to resist heeling turning to uncontrolled rolling...



  30. #150
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    We now have a perfect displacement area...


    ....Well, that is until someone shoves a huge dog or the wife in the bow and it all changes shape or just sinks.

    Er.....

    Perhaps we should talk about sides, freeboard, displacement weights and the effect of adding cargo, lol.

  31. #151
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Sides....

    Pretty obvious that they are there to keep the water out.

    They must also increase the width of the boat as it heels. This is done by making sure that the distance from the boast centre of gravity to the edge were the side comes up out of the water keeps getting bigger as the heeling angle is increased.

    The top of the sides - on a canoe, must be low enough that the paddler, while sitting on the seat, or on the floor, does not bash his elbows.

    Havent tried to paddle round something in a hurry with a thumped funny bone, and Im hoping to avoid it.

  32. #152
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Sides.....

    Freeboard.

    Er....I thought this was something to do with cheap guesthouses, or staying at the parents place.

    Turns out its the sides of the boat stuck out of the water when the water is flat and the boat is sat normally.

    I also thought that if the waves were 5 foot tall, I would need 5 foot tall sides.

    Turns out I was right.

    Although only if the waves are the same sort of length as the boat.

    Mothers day... Looks like Im not going to be able to draw these pics until tonight.


    Grrr...

  33. #153
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Hmm...

    These pics took longer to make than I expected.

    I still havent got the words on them right. Sorry.

    Im going to post them 'as is', as I havent enough time to fix them at the mo and dont want to hold off any longer.

  34. #154
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Little boat in long tall waves, rides them without problems - despite being considerably shorter than the waves are high....



    Now one half the height


  35. #155
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    As the wave length gets shorter, the boat struggles to change direction at the bottom and keep its bow out.

    When the wave length is slightly shorter, no real problem...




    ...and shorter again....



    The bow is getting lower in the turn now.

  36. #156
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    The corner is getting too sharp for the length and height of the nose of the boat...



    ...now its near its limit (please ignore the wave lenths)


  37. #157
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Eventually, when the wave length gets too short, this happens....



    ..Thats not really where you want to end up.

  38. #158
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Obviously, 10 foot tall waves...

    Not in my harbour.

    Max there is only 2 ft, so Im safe.

  39. #159
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    The shorter the distance the wind has to run over the water before it gets to your boat, the shorter the length of the waves are.

    2 ft waves hitting a 2 ft boat arnt expected to be anything like as bad at the 10 ft waves earlier...



    However, as the boat crests a little wave, the bow drops into the next trough with inertia and goes down deeper than it would if the wave dropped it slower...

    The shorter the length of the wave, the faster it drops the boat....


    This boat is getting close to its limit despite having plenty of boat out of the water when at rest.

  40. #160
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    These numbers are correct.

    This boat is taking on water every wave, not because of the height of the wave, but due to the waves short length dropping the bow...


  41. #161
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    A boat thats going to be used exclusively on canals, where any traffic will be paddled, or out in ditches, minimum freeboard isnt a problem.

    However, anywhere near motorboats, where wind gets 3 or four football pitches after running off a mountain, or off a sea....

    You can need as much freeboard as at sea - or more.

  42. #162
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Another stupid question....

    Why havent Kayaks got 3 ft of freeboard?

    Kayaks and some specialised canoes are designed to be constantly flooded. They have big air bags in the ends to stop water filling them up, and they just bob back to the surface like a held down football when its released.

    Ok....Why dont I want 5 ft of freeboard on my 14 ft long canoe as Im going to use it in wind on the lake?

    Windage.

    The wind isnt very smart. It hasnt sussed that we only want it to blow us along in the direction we want to go, or to fill our sails with just the right amount to make us go at the speed we want.

    The stupid stuff keeps blowing all over the place.

    It hits the sides of boats, and especially canoes and blows them sideways, or turns the lightest end away from where its blowing from.

    This can be nearly as much of a pain as the boat sinking.

    Well.....Nearly.

    Thats why canoes are usually around one to one and a half ft tall. 30cm - 45cm.

    The bows, and often the sterns are higher to stop them sinking in short length waves - or chop (choppy waves).

  43. #163
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    THe sides of the canoe are the pieces of canoe, from the bottom up to the top of the tumblehome.

    On the ends, this is tipped forwards to make the boat climb over waves.

    Canoes are traditionally very pointy, which encourages them to pierce through waves initially, before the wider area a foot back lifts the canoes bow up.

    I believe this is why many canoes are traditionally built with very high noses.

  44. #164
    Join Date
    Jan 2011
    Location
    S-o-T, U.K.
    Posts
    3,339

    Default

    Phew ... I'm glad I made it past all those waves, they were making my eyes go funny and I was feeling a bit queasy for a min there.
    Now I know why my bailer and sponges are such essential pieces of kit, the gunwales on my MRE16TT are just about flat with no high noses at all

    Brilliant stuff.
    DCUK
    Can't ytpe or roopf read

  45. #165
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Sponges.....?

    Bailers?....

    Er....

    I use sponges to wash the car.

    Bailers dont work under 3 mph, which is usually where I live when my boat takes on a little water....

    I simply sorted mine so it will still float if it gets a bit wet, so I can just paddle to the nearest beach and tip it over.



    I want higher ends on my next one though.

  46. #166
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Displacement....

    Need to have a closer look at displacement.

    Our Armless paddler.....Fred, has just made a nice new boat.

    Hes very proud of it....

  47. #167
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    He thinks it is perfect.

    When he sits in it, the bottom and a small part of the sides go into the water.

    If he heels it, the shape makes the water push back, making it very stable.

    He is happy.


  48. #168
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Unfortunately, he has a cousin - who goes everywhere with him.

    His cousin is called Duh. Hes also green as he is usually seasick.

    Fred is still happy. The water is still part way up the first sides. The boat will still cause the water to push back when it leans.


  49. #169
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Seems Duh has heard that when some people go camping, they whittle spoons.

    Duh doesnt like wooden spoons. He likes metal spoons.

    He wants to feel a part of it all.

    So hes bought a big box full of tent, sleeping bags, food, cooker.



    Ooops...Nearly forgot....

    He also bought his hammers and his anvil.

  50. #170
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Fred is pretty sure that he has a problem.

    He thinks about it for a bit.

    AHA!

    Fred built a bigger boat.


  51. #171
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Er.....

    I think he misjudged Duh.

    Seems Duh likes to hug his anvil while he vomits over the side....


  52. #172
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Fred could save himself a whole lot of trouble by simply shooting Duh.

    However, there might be some reason why he shouldnt.

    If Fred works out exactly what the poor boat has to put up with, and designs accordingly, puking Duh and his anvil do not have to be a problem.

  53. #173
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    When it comes to displacement, you need to know how much cargo the canoe has to carry. You need a maximum weight, and a minimum weight.

    Maximum cargo includes you, your clothes, your emergency kit, your camping kit, your food, your water, your maps, your kids, your partner, your dog, and even the anvil, if you intend to put it in the boat.

    At maximum load, you must design your boat to still float properly for what you wish to do with it.

    The boat must also still function when its unloaded and just you in it - if you intend to use it like that.

    At maximum load, the sides must still slope out at the waterline.

    At minimum load, the ends must be far enough down in the water to allow you to be able to paddle in a straight line - if thats what you need it to do.

    The trick is to actually achieve this.

  54. #174
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    If you look at pretty much any of the plan sets available, they all have maximum and minimum load limits.

    This is to make sure the finished boat will actually perform as required.

  55. #175
    Join Date
    Jan 2011
    Location
    S-o-T, U.K.
    Posts
    3,339

    Default

    Quote Originally Posted by No Idea View Post
    Sponges.....? Bailers?.... Er....

    I use sponges to wash the car.

    Bailers don't work under 3 mph, which is usually where I live when my boat takes on a little water....
    My bailer is low tech and works at any speed

    The sponge just mops up the dregs ... or is saturated & thrown at others in games
    DCUK
    Can't ytpe or roopf read

  56. #176
    Join Date
    Sep 2008
    Location
    Nailsworth
    Posts
    456

    Default

    1. Shoot Duh!

    2. Tie the anvil to his lifeless body.

    3. Throw them both overboard!!

    Problem solved
    Keltoi and associates - The sick and the wrong!

  57. #177
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Hi Friend Potty

    Sawn off Fuel can! Excellent!

    Lol Keltoi

    If only life was always that simple!

    Trouble is that if Little Idea shoots this Doh....



    He will end up in bed with no tea and grounded lol.

    Sometimes, its better just to build a bigger boat and then shove stabilisers on it.

  58. #178
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Another stupid question....

    How do you work out how much weight you are going to carry?

    If you havent been canoeing already, its going to be a bit hit and miss.

    If you have and know what you need to carry, its a lot easier.

    The software will work out the weight of the boat, so you needent worry about that.

    You will need to calculate the weight for anything you add to it though.

    Paint, epoxy and tape, varnish, rubrails, keel...

    Mast, Sails, Rigging, cleats...

    Anchor, anchor warp, ground trolley, paddles...

    Buoyancy devices - tanks, bags, polystyrene...

    Seats, painter, ropes, D rings, bailing devices - buckets, self bailers....

    Emergency equipement - coat, dry clothes, fire, food, shelter, first aid kit, water, storage bags, tape, fibreglass kit, cable ties...

    Comms - Mobiles, cameras, GPS, Vhs radios, maps, pens compasses, lights....

    Worn kit - wetsuit, dry suit, pfd, whistle, compass, walkie talkie, boots, hat sunglasses...

    Fishing kit...

    Camping kit - tent, tarp, hammock, maggot, etc...

    Wife, Husband, Kids, Dog - all their kit...

    Even the anvil and hammers.

    We didnt have individual weights for our kit, etc...

    So....

    We packed our kit in its bags, with our wearing kit and PFD's

    and simply got on the bathroom scales...



    We used this to work out how much buoyancy we needed, but it will work the same for this.

    You need two weight sessions. One with the max you will carry, and one with the striped down kit.

    This will give you the weight range you need to cover.

  59. #179
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Er...

    I am too fat. Me and my kit make the scales cry.

    So now all I need to do is weigh me, then the kit, then the boat materials.

    Er....

    me was easy....



    Its the paddles and anchor thats tipping it off.

    Going to do the paddles with the boat parts.



    We will sort out the weight of the boat later.

  60. #180
    Join Date
    Apr 2011
    Location
    Poole Dorset UK
    Posts
    2,151
    Journal Entries
    622

    Default

    Ok.

    Its probably about time we have a good look at boat construction.

    Im not going to talk about kevlar, carbon and moulded fibreglass.

    Its not that easy to work in and we are looking at a first-ish, from scratch boat build project. That lots a fair bit more advanced.

    Three main methods are readily suitable:-

    Cloth over a frame, waterproofed - canvas.

    Stitch and glue.

    Lapstrake, or clinker.

Page 3 of 5 FirstFirst 12345 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •