Thread: questions

Ramps and Michael,
Frankly, you guys can bounce questions and answers as much as you like - believe me I am finding it very informative.
You are raising issues that I would not know to ask about.... I've been off to look at the Redbird and Bear Mountain sites, a Canadian wood canoe forum and searched Wik for a few terms. Its all good, and I've been content to 'sit back, listen and learn'.
I have not been able to speak with, and listen to, someone that has made a stripper, or a boat designer - until now! BM and WD contributed a lot, so are you guys.
Thanks, can you stop worrying that you are "wrecking my thread"? KEEP GOING!

Jack,
My initial questions are based in my complete lack of knowledge. That has changed just a tiny bit, but I'm still happy to call myself ignorant!

My 1st stem question was mostly based on an inability to understand the function of having 2 stems, i.e. wouldn't one be sufficient, why the need for an outer? I was imagining the work to shape the inner, fair and match the strips, then form the outer. I was thinking that 1 inner, fair and match the strips, then glass and epoxy and add a brass rub strip seemed 'easier'. This led me to think of doing a rebate on the inner. i was thinking of the economy of effort - basically looking for a lazy way.

The mould board question: I was thinking "why not put the 1st mould board up very close to the 1st stem. Do away with an inner stem (& outer), use an 'outer moulding pattern' and fill the area between the mould board and 'outer moulding pattern' to hold a expoxy and reinforcing cloth (what I call a 'composite material') to create a solid piece that acts as inner and outer stem. When the composite sets, remove the 'outer moulding pattern'. Basically 'cast' a piece of solid plastic. It was mentioned that there would be a trade off for weight, and that perhaps I shouldn't experiment on a first build, rather stick to a tried and true design and get some experience first.

An example of what I call a 'composite material' is the process of using layers of veneer/cloth/carbon fibre/canvas with a good epoxy that affords some small amount of flexibility. Veer, epoxy, veneer, epoxy and continue putting down layers, then clamp and let set.
If you do this with plane shavings, and use the right amount of epoxy, you get a really stable material that almost looks like wood, with the strength of epoxy. I learnt about this from Bridge City Tool Works "Juara" wood. Basically it takes advantage of the superior strength of epoxy, with the grain of wood. This ties in well with your comment on laminations - think of it as lots of really thin laminations.
Cameron Potter on this site does the same thing, but uses cloth instead of veneer/shavings - and turns stunning, strong, lathe tool abusing, pens out of it. The first denim/epoxy block I made has been sanded, drilled, sawn, filed, rasped and had threads tapped in it and bolts fitted. Tough stuff.

I've got an inquisitive mind.

Keel: I accept that it is a bad idea, and that the form/design of the front and rear (prow and bow?) actually achieves what I was thinking of.

The "Adirondack Guide Boat" on your website looks good. In the top piccy it seems to be hardly sitting in the water. I guess it can carry a fair load?
Are there any other pics that you can post into this thread? I could not enlarge any of the pics on the website. Its a bit big for me, but looks good!

Thanks for your input - it is much appreciated.

Clinton,
In fact you don't need an inner or outer stem at all for a wood strip canoe. If you pick up a copy of Gil Gilpatricks book you will see that he built boats without using stem pieces at all.
He simply shaped the stem form and worked the strips together at the ends. Then he sanded, faired and glassed them. There are a number of people who build like this. For me I don't see the bennifit to doing this. You have to spend a lot more time fitting the strips and in general they do not come out looking as good.
Where the inner stem is actually a structural member of the boat that helps to hold the boat together and gives a good landing for the strips, the outer stem of the boat serves no purpose other than to protect the stem and to add a bit of class. Before you attach an outer stem piece, you glass over the stems. You could simply double up on the glass and eliminate the outer stem piece if you wanted, but I don't think the boat would look finished.
Experimenting is good, I do it all the time, but be carful how you use epoxy on a real project as it has very different properties than poly resin. Epoxy is very brittle by its nature. When used in conjustion with glass it gains a bit of flexibility becasue the glass holds it together but by itself it will crack fairly easily under flex stress. Tony Delima , the inventor of MAS Epoxy is a friend of mine. If you ever have questions about epoxy and you want an answer that you know is right he is always willing to talk to you. You can find his number on his web site Masepoxies.com Great guy and way smart.
Laminating the stems is as simple as can be if you have a tea kettle. In fact the first time I did it was in my bath tub with hot water 25 years ago. Worked well but took days for the wood to dry enough to actually laminate.
I love the Adirondack guide boat. It has been a favorite of mine for 20 years. It just took until now for me to get around to making up a set of plans for it. The boat is decieving from the above water view. I posted a pic on the web site so that you could see the lines below the water.


The boat is about the same size as a canoe. It is only 16 foot but the beam is about 10 inches wider than a typical canoe. I have another boat plan and video which is built similarly but is smaller and lighter, it is called the little rob. A very traditional Rob Roy style canoe. You sit on the bottom and paddle like a kayak. This is the go to boat for me becasue it only weighs about 30 LBs and I can throw it in the truck and be on the water in minutes.


If you want to see some building pictures, including the stem lamination you can find them here at http://www.sandypointboatworks.com/P...mtheshop2.html
I have a couple dozen pictures of the Adirondack Guide Boat if you are interested becasue a customer just sent me a bunch from one he built. Give me an idea of what you would like to see and I am happy to post them.

jack

Jack,
Any pics are good - how about you put up whatever you think you can use to educate me? Mik said that "Eyes are really important in understanding boats", I guess that I'm asking if you can use a pic to tell me how the boat lines make it "fast straight and stable". If you could do that it would help me.

Also, what was the use that the boat was designed for? Was it a day tripper for getting up and down a waterway, for extended trips, a workboat? What sort of weight does it carry?

You are in North America - the Ma in your contact address is Massachusetts?
I'm a bit envious of you guys and your access to the waterways and rivers that are in North America. 80% of Australia is desert, and the only river that I've seen that compares to anything you have is the Ord River in Western Australia. I haven't seen them all, but most of our rivers are muddy and short.

Thanks,

Howdy Clinton,

Originally Posted by Jackbat

Straight

The tendancy for the boat to go straight comes from three places

One is the same as the Classic canoes. Have a look at the Body Plan - the line drawing in Jackbat's post immediately above. Note how the sections are convex curves (looking from the outside of the boat!) but down near the bottom they become concave. This has the same effect as the keel.

The other reason is because the width of the boat at the waterline is quite narrow - even though the boat is quite wide above the water. Something long and thin is much harder to turn than something short and fat.

Note how there is not much difference in depth between the bottoms of each section - this shows the bottom doesn't curve up much. This is called rocker. This boat and Redbird canoe have relatively rocker so are good straight line machines, the Prospector has a bit more rocker so has a balance between turning and going straight.

Fast

Narrow usually means fast - this boat is narrow at the waterline.

Also the low rocker makes the boat faster.

The reason for both is that the water is pushed down and out the minimum amount so the water can move through. Saves energy.

Stable

The guideboat is quite narrow on the waterline so it might have a feeling of being a little bit unstable at small angles of heel. But it is much wider than a canoe at deck level - so as it heels a bit more the stability will pick up very quickly.

The beam affects the stability of a boat proportional to the cube.

So if a boat is twice as wide then the stability goes up 2 cubed ie 8 times.

In this case the beam of the Guideboat is around 4ft (from memory - Jackbat - correction?) so it has about 33% more beam than the canoes that we have been talking about. So cube that to get the change in stability - 1.33 cubed = 2.35. So the guideboat has *around* 2.3 times the stability.

the *around* is because this proportional rule depends on the hulshapes being identical apart from beam - but the guideboat shape is different of course - so the analysis is only approximate.

Hope I have explained the jargon well enough.

MIK

Originally Posted by Clinton1

You are in North America - the Ma in your contact address is Massachusetts?
I'm a bit envious of you guys and your access to the waterways and rivers that are in North America. 80% of Australia is desert, and the only river that I've seen that compares to anything you have is the Ord River in Western Australia. I haven't seen them all, but most of our rivers are muddy and short.

Thanks,

Dont be envious Clinton... get the hell out and have a look around!! MAN Aussie has some of the best waterways in the world excluding NONE!

The Ords good for sure but then the Swans excellent as well long and with everything from fast water (Avon Decent anyone?) to slow shallow water to deep water... Canning River, Murray River, (to name but a few) Estuarys: Lauschinalt and Mandurah (and others) along with many Lakes Dams and offshutes... muddy shallow? Not to many that Ive seen over here... theres all the waterways you could ever want over east... some shallow and muddy most not... how fars the Murrumbridgy go? The big Murray River how fars that? in all their lengths there must be some good waters... Im unfamiliar with Queenslands rivers and such but Im bloody sure theres some brilliant places on them!! gotta get out and on the water to find them maybe but theyre there mate

As for much of Aussie being dry well the Gascoyne River is dry for 7 years generally then they have a cyclone and it floods for weeks after its bloody fantastic!... If your game and stick to some basic guidelines the Mary River is an awesome sight to paddle as is the Kathrine River... basic guidelines? Such things as being aware that Crocs live there and Crocs just plain dont care about you one iota other than as tucker is the best bit of guideline advice anyone can give or get up there but still if you game (Barramundi anyone!!) and careful its bloody brilliant!!

I think such things as the intercontinental waterway is something we here in Aussie should hound our polititians for... imagine a canal large enough for a couple of sailboats or powerboats to pass each other without disturbing their wakes going right around Aussie?!! MAN!!! HECK even one straight across the damned Nallabor would be most excellent!! Id rather take several weeks transversing Aussie in a boat than in a ruddy car

To my mind there is NOTHING to be envious about the US waterways over our own!

Originally Posted by Wild Dingo

I think such things as the intercontinental waterway is something we here in Aussie should hound our polititians for... imagine a canal large enough for a couple of sailboats or powerboats to pass each other without disturbing their wakes going right around Aussie?!! MAN!!! HECK

That means I could take my canoe down to somewhere near Deepdugs house drop it in, head left and hit Midges house in about 6 months.

Howdy - just dropping in for a quck cuppa.

MIK

I like my rivers clear.
Only seen it three times, the Snowy up in the Snowy's foothills (dodge the rocks due to the level tho), the NQ rivers in the wet season (they flow a bit fast then!) and the Ord above the dam.
Every other river has just been thin mud!

I'm yet to go to the southern part of WA, and Tassy.

The Ord is bloody fantastic, under rated, remote, hot, humid - which is good cause it keeps the population down.
North America seems to have a lot of wild rivers that flow clean and clear... benefits of two big mountain ranges running either side of the country I guess.

Hi, I'm new here, hope you can help me out. Could anyone give me their opinion on whether paulownia would be strong enough for a sea kayak used in the surf? When I get round to it I intend building a low volume day kayak, possibly a Black Pearl. http://www.thomassondesign.com/edoc/eblackpearl.php

Clinton, not sure if you're aware of these sites but there's some good info on sailing canoes at http://dragonflycanoe.com/ and http://freepages.genealogy.rootsweb....e_sailing.html

If you are looking for clear, large volume rivers to paddle on there are quite a few in New Zealand.

Kelvin

G'day Kevin, welcome to the forum.

I'm sure the guys will have an answer for you shortly.
I'll have to check out those links - thanks!

Hi Kelvin,

Paulownia won't be a problem, but depending on what you mean by "used in the surf" the black pearl could be!

If you are paddling out to go for a bit of an open sea jaunt, no problems, although you'd need to take a bit of care coming in.

Those loooong skinny bows may be great for paddling through waves, but you don't want them to dig in be coming down the face of a short wave!

For surfing, usually kayaks are quite short, with a relatively flat bottom and hardish chines that can be used to dig into the side of the wave for tracking on the way in. Or has all that changed in the last few years?

Cheers,

P

"Used in the surf" includes both the getting in and out and surfing. I have short kayaks for whitewater/surf but a lot of guys take there seakayaks surfing as well. I currently have an NDK Explorer sea kayak which I've only pitchpoled once but would like something lighter and sportier for day paddles and playing. Glad you think paulownia will be up to it, now I just need to get organised enough to build my new shed so I can start working on a kayak. Any suggestions on thickness for the wood and what weight of glass would be best?

thanks
Kelvin

Hi Kelvin,

For a surf landing that goes OK there is no difference in timbers of course!

But if something goes wrong and you wrap the boat around a rock there will probably be little difference between timbers - if it is hard enough to damage one of them it will be hard and heavy enough to do significant damage to all.

I haven't got enough time at the moment to dig out an old spreadsheet I wrote as part of my engineering course to get a quantitative answer about strength and impact absorbtion, but I can suggest a ballpark solution.

Normally strip boats use 6mm Cedar. If you go to 7mm Paulownia the strips will have pretty much the same impact absorbtion and tensile strength.

But because of the added thickness the glass will be more effective in stiffening the skin.

And because Paulownia is lighter than WRC you won't have added any weight.

I don't know what the sea kayaking hotshots are using for glass. For normal use 6oz (200gsm) is fine, but there might be some info about boats that are going to be surf landed on some specialist sites on the net.

Or in the plans!? The info should be there.
______________________________

Just did a fair bit of fishing through Nick Schade's site. It looks like the general run of kayaks are glassed with either 6oz or 4oz.

If you are likely to be wrapping it around rocks I would take the heavier!

MIK


MIK

Thanks Mik, from what I've seen of long composite kayaks wrapping in whitewater I don't think it's feasable to build a kayak to withstand it. I'll see what the plans say and decide from there.