Thread: Eureka Canoe

Howdy.

Generally double bladed paddles require the boat to be not too wide nor too high off the water - so they are not the most efficient solution for a canoe - much better for a kayak.

But at the same time I often think that having two single paddles plus a double paddle on any canoe makes a pleasant change when just stooging up a backwater somewhere or on a leisurely downwind drift if one of the crew wants to laze a bit.

Yeah - have two nice single paddles and buy an el cheapo double just to have handy.

A two person canoe will be faster, more capable in wind and rough water than the two singles - and your wife won't have to hang around and wait for you to catch up all the time. Transport is also easier.

MIK

Free Paddle plans are at - http://www.storerboatplans.com/Paddles/FreePaddle.html

Another method is to learn how to efficiently do the "J-stroke". I learnt in scouts and still use it if I am the only one paddling in a canoe.

Originally Posted by Wood Butcher

Another method is to learn how to efficiently do the "J-stroke". I learnt in scouts and still use it if I am the only one paddling in a canoe.

Oh you smarty pants - I bet you do it with the boat heeled like the old trackers!

Works best with a hundredweight of beaver pelts in the middle of the boat!

But it is an essential skill - making the canoe go straight while paddling on one side only. Like learning to scull a dinghy with a single oar over the transom.

Very Cool!

MIK

Hallo Chaps,

Just found this forum yesterday, I finished building my Eureka155 "Miss Trish" and launched her on Sunday, June 11!
I was very proud of her and couldn't stop smiling on the day.

She felt quite twitchy, not as stable as I had expected! I stayed upright, but one of my friends tipped over into the freezing Derwent!

I haven't tried it with two aboard yet - the queue of people waiting for a paddle reduced drastically after the rollover!

I see that Deepdug had a similar experience. I measured the beam of my boat, and it is 770mm.

I've also put the seats in with the bottom supports on the chine, so they are 150mm off the bottom of the canoe.

I used 4mm gaboon, and coated the bottom with a layer of fibreglass, up to the chine. I used 6mm for the seats and the decks.
I started on Boxing day, so its been 6 months, but we moved house in there as well so construction was interrupted.

It took me about 110 hours and about $1100.

Cheers

Woodzzzy

There are some of the problems!

It is supposed to measure 856 at the centre spreader - a fact I was only told after I had tipped it over.

Also the seats turn out to be too high for a 90 k person if they are on the chine.

I have spread mine to achieve the correct width but I have not yet fitted any seats as I want to be sure that I feel as comfortable in the Eureka as I do in all of my other canoes.

I don't think that Mik or Bittingmidge like me to talk about this but really the plans should have covered both of these areas!

It was -0.9 this morning at my home near the beach in Adelaide so canoeing is on hold for the moment. When more temperate weather returns I will resume my sea trials.

By the way, Miss Trish looks very nice!

Nice one Woodzzzy, I'm hoping to have mine finished one day!!

As with Doug's boat, it is amazing how narrow yours looks relatively, mine turned out a good two inches wider but still below the design width. Mine's currently decorating the floor of my office, which isn't a great place to keep a boat!

Originally Posted by deepdug

Also the seats turn out to be too high for a 90 k person if they are on the chine.

After reading this comment, I dropped mine somewhat, but have since received more feedback from other experienced canoists, and will raise them back to the designed position.
After our test paddle, I don't think that will affect stability, which isn't a problem on our boat.

I have spread mine to achieve the correct width but I have not yet fitted any seats as I want to be sure that I feel as comfortable in the Eureka as I do in all of my other canoes.

I don't think that Mik or Bittingmidge like me to talk about this but really the plans should have covered both of these areas!

I don't know why you get that impression Doug? This whole thread is about sharing our experiences and assisting anyone else that comes along.

Mik solved the issue a long time ago https://www.woodworkforums.com/showpo...6&postcount=79 and as far as I know hasn't been backwards in coming forward!

The beam differences we have experienced is a function of the stitch and glue process, but as Mik was concerned about the wide range of dimension between your boat and mine, he's now amended the instructions to include a temporary centre spreader which will get rid of that one variable.

Please don't hold back because you think either of us "don't like you talking about it". If you hadn't posted originally, my boat is close to the designed tolerance and the issue wouldn't have been found.

cheers,

P

Aaarrr Me Hearties!

Took Miss Trish out for her second try today.

Falling over in water in the first 30 seconds is good, cos it gets it out of the way! I think I need a door in the side so I can slide in in the seated position!!!

I put in a temporary lower seat to see how much difference it made. She felt a bit better. Then I put in about 30kgs of weight in the front, That was a bit better also.


Also coming back into the beach, I had to time it right, so that I could spring out as the bottom touched the sand...that was the master plan...
the comment I got from the Real Miss Trish was ,"Um, zero points for the dismount!!!"

So it looks like I will be lowering the seats...So while I'm at it, I may as well cut out the centre spreader and push it wider.

Or would I be better working on an outrigger or stabilisers and leaving the seats etc where they are???

Whaddaya reckon, Shipmates?

I reckon if you are going to lower the seats, then you've only got to make a new centre spreader, so do it! Push it out. It seemed to make quite a difference for Doug. Check out Mik's post somewhere here about the theoretical stability difference, it's quite a lot.

I've been sanding mine today! woo hoo progress again. might even give it a poxy touch-up tomorrow! Then I look at the seats, and think how we felt quite comfortable with them low, and wonder if I'll ever get round to making them taller. Probably not!

Cheers,

P

Originally Posted by Woodzzzy

So it looks like I will be lowering the seats...So while I'm at it, I may as well cut out the centre spreader and push it wider.

Or would I be better working on an outrigger or stabilisers and leaving the seats etc where they are???

Whaddaya reckon, Shipmates?

Howdy Woodzzzy,

If you are pulling the seats out you may as well cut out the centre spreader and push the boat out closer to the proper width.

Even the gain of a couple of inches will make quite a bit of difference to the current sense of uncertainty.

Doug has gone through this process and might have an idea of how far you can go before something breaks - which he did and had to fix it up.

Outriggers will make the boat harder to paddle in general but can provide the basis for an awesome sailing machine (which they will also do for any canoe) You can have a set of my outrigger plans free if you like (and that goes for you Doug too if you want a set).

It is also possible to mount a small outboard to the aft outrigger to make a fishing/diving platform.

But as far as producing a good paddling boat I think outriggers will mean that the wind catches the boat too much making it hard to paddle.

(comment - mik's bolding not Deepdougs)

Originally Posted by deepdug

There are some of the problems!

It is supposed to measure 856 at the centre spreader - a fact I was only told after I had tipped it over.

Also the seats turn out to be too high for a 90 k person if they are on the chine.

I have spread mine to achieve the correct width but I have not yet fitted any seats as I want to be sure that I feel as comfortable in the Eureka as I do in all of my other canoes.

I don't think that Mik or Bittingmidge like me to talk about this but really the plans should have covered both of these areas!

It was -0.9 this morning at my home near the beach in Adelaide so canoeing is on hold for the moment. When more temperate weather returns I will resume my sea trials.

Hi Doug,

You are completely right about the beam of the boat - I should have put a centre measurement in there as a failsafe - but I thought that locating the width at two points like the smaller boat would work as well as it did there.

The original smaller boat was designed by me then the building process was proved out over several boats by Duck Flat. I did supply a centreline beam measurement to them but the plan that Duck Flat developed didn't include the centre measurement supplied by me - because it wasn't needed as the beam was located at two points closer to the ends of the boat. And those plans worked fine for that boat.

Then when I used their plans as the basis for the info for the bigger boat I just lifted their assembly method - and used all their lovely hand done drawings of the assemble stages.

So I wasn't witholding information about the centre width of the boat as you seem to be suggesting a little - waiting until after you had a problem...

... I just wasn't aware of the problem of the variability of the beam until you got back to me - and the information you gave me in way of photos and measurements was extremely helpful it working out just where to change both the drawings and order of procedure so it won't happen again.

I am not dodging responsibility on not having the measurement there, it was a mistake and I corrected the plans within a few days including substantial rewriting of some of the procedure to cover some of the other points you made in emails (the other important area was in resolving the problems you had with the deck (now has a centreline beam and the clamp on the bulkhead is sawn rather than bent to the curve) - there were some other good points that enabled me to make the procedure a bit easier.

As far as the seats go - we used lowered seats when we popped Midge's in the water and the boat didn't scare a number of different crews and weight combinations who took it for a bit of a blat - not even in the dismount (I'm really sorry Woodzzzy) - so I think the stability is OK with the original seat heights and the problem was in the beam.

Some very serious canoeing types in Melbourne are building one now and are going to do some experimenting with the seat height - they want to go a lot higher to increase paddling efficiency so it will be interesting to see what they can get away with.

They are building it really light to try and get the weight down close to 15kg using 4mm ply and Kiri/Paulownia for the trim (lighter than almost anything else other than Balsa).

So anyway Doug - though I might not LIKE that you talk about the problems that were there - I am REALLY GLAD that you did.

I'm in your debt.

Michael

Thanks Mik, I'll take you up on your offer of outrigger plans. I think I will try an outrigger before cutting anything out.

I weighed Miss Trish, she is 23kg. I used Oregon for the Gunnels etc. I did some quick calcs, and I reckon that every 10kg will put her about 10mm lower in the water. so water line is at the chine with ~ 100kgs. If I push the centre spreader wider, say 75 mm, Sheer is about 200 above chine, which is ~ 100 above the bottom - the extra width at waterline would only be about 25mm...would this make much difference ?

Cheers

Howdy Woodzzzy,

Got your email too - will reply thisevening.

The inch is only part of the story.

Initial stability - It is an important inch because the initial stability is from the beam cubed - so if the beam is increased 5% it will have 1.05 cubed as an effect on the stability through very small angles of heel. ie 1.158 - so stability through SMALL ANGLES will increase almost 16 percent.

Reserve stability - is as the boat rolls over more than a few degrees so that it starts leaning over further onto its side.

Again it is a cubic relation - so if you increase the beam at deck by 12% then the reserve stability will have a peak that is 1.404 higher - a massive 40%. So as it heels it will feel like it is gaining stablity rather than rolling like a barrel.

If you imagine two versions of the Eureka using the narrow bottom shape from the initial stability example above.

Version one has the narrower shape continuing above the waterline - it just doesn't get wider.

Version two flares out to a beam of 5 feet (1.5m) above the waterline.

So as version one heels the feeling of stability quickly drops away - meaning that if you go over a bit - you are pretty likely to go right over. the boat doesn't build stability but neatly and smoothly rolls over.

The second version will roll over so its full width contacts the water and has huge stability. But the beam will mean that it can't be paddled effectively and will be really slow in all conditions - and downright dangerous in wind and waves - totally uncontrolable.

So the trick is to balance the design - too much stability and it becomes a bugg*r to handle particularly in winds and waves. And it will be slow because of excessive wetted surface and an excessively blunt shape - this is the case with most fibreglass canoes. Too fine and it will move along nicely but require a really experienced paddler to keep it up - think of the ultra narrow, ultra twitchy Olympic K1 kayaks

There are other ways to get reserve stability:
Low centre of gravity (which doesn't affect initial stability much at all)
High topsides so water doesn't get into the boat as it heels
Side decks so water doesn't get into the boat as it heels
Using crew weight to keep the boat level.
Size - double the dimensions of a boat and it will be 16 times more stable - halve them and it will be 16 times less stable.
(These are the factors that are used in the plumbsided square boats like my Beth canoe and Bolger's many squareboats that give them good stability).

Rocker - if you push the middle of the boat out to increase beam that is not the only change. It pulls the ends of the boat higher relative to the middle. This means that more displacement will be carried on the mid section rather than the ends.

The ends are narrow - so don't contribute much in the way of stability - the mid body of the boat is wide so contributes most of the stability.

So more rocker increase the effect from the stable mid section of the boat.

Centre of Gravity - Moving the mid section of the boat lower also moves the centre of gravity lower. This is also a cubic relation - so even though it might only be a centimetre it might actually start figuring in the feeling of stability as well.

Experience - your and Dougs boats in their narrow version feel really tippy. Midge's doesn't. The difference in the beam is the only difference. So yes, increasing beam will solve the problem.

When Doug increased the beam closer to what it should be - the boat was a lot different in the water. As he has said he is not waiting for some warmer weather to see if he can get his confidence back in the boat.

So I changed the plans after Doug's contact to MAKE SURE that the same problem wouldn't occcur again.

MIK

Originally Posted by Boatmik

Rocker - if you push the middle of the boat out to increase beam that is not the only change. It pulls the ends of the boat higher relative to the middle. This means that more displacement will be carried on the mid section rather than the ends.

I remember now.

I kept temporary Gunwhales on the whole time and was a bit fussy about keeping them fair, which probably accounts for my beam being closer to plan, but even so it was remarkable to see the hull change shape when they were unclamped.

The bottom was just about dead flat for it's whole length. I did measure the rocker for various beam dimensions at one point, but I've got no idea where the numbers are. I'm thinking that pushing the beam out 75mm at the centre will give an extra 25mm or more rocker.

It would be good to record I think!

Cheers,

P