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PostPosted: Wed Nov 18, 2009 1:47 am 
The Dyson Baidarkas like a lot of aluminum frame SOF boats is made out of

0.75in OD x 0.049in wall 6061 T6 aluminium tube and
0.50in OD x 0.049in wall 6061 T6 aluminum tube.

The most common length seems to be 12 foot so obviously at some point
the tubing will have to be joined to build a 5.28m or a 7.3m Baidarka.

From my search of the Net is would appear that an insert of 4-6 inches of
0.625 OD x 0.0.49in wall 6061 T6 for the 0.75in OD tube and
an insert 0.375OD x 0.049wall for the 0.50 OD is what is required.

From the Dyson book Baidarka and from the Baidarka Mailing list archive
is would appear that this is held in place with an epoxy (West Systems?)
or by crimping the tube with a hole punch or modified tube cutter.
(Rivets or screws are another method).

I have been warned that the variations in the manufacture of the tubes may be
enough that I would have to physically check that the inserts will fit inside the large tube.

Am I on the right track or barking up the wrong tree?
Has anyone done this or similar?

Thanks.

Tim W


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PostPosted: Sat Nov 21, 2009 3:54 pm 
Tim,

Looks like you're stuck with me again :lol:

Quote:
The most common length seems to be 12 foot so obviously at some point
the tubing will have to be joined to build a 5.28m or a 7.3m Baidarka.


Do you have access to Imperial sized tubing in Oz ? Read the following aluminum tubing link ( several pages ) by clicking
on the "Next Page" key at each page. http://yostwerks.com/Frame4.html. I'm assuming you haven't read my manual based
on your questions ? 6061-T6 may be harder to find in Australia, with 6063 being more common as I recall.

In the US 12' or even 20' (locally) would be a common size, though for shipping , there is a much greater cost associated
with shipping 12 footers vs 6 footers. I have mine shipped as 6 footers by standard ground transport from "Texas Towers". In Oz, length
and shipping costs would likely vary from the above. If you are purchasing locally, then transport may not be an issue. There is no advantage
building with 12 footers vs 6 footers... just a few more inserts to cut.

Quote:
From my search of the Net is would appear that an insert of 4-6 inches of
0.625 OD x 0.0.49in wall 6061 T6 for the 0.75in OD tube and
an insert 0.375OD x 0.049wall for the 0.50 OD is what is required.


6" inserts are my standard size. Using imperial measurements, .049 wall tubes will telescope together
in standard 1/8" increments ... 1", 7/8", 3/4", 5/8", 1/2", etc. up and down the scale. I'll let you do the decimal feet conversions.
Of course, the wall thickness of the insert is irrelevant, only OD. If you will be using metric ?... that would mean a different fit
vs imperial inserts.

This works also for .055 wall tubing, but the tolerances will be tighter. In the link above, the .049, .055, and
metric wall tubes are covered. Metric tends to be a very tight fit ( or very loose as the case may be) , and for a folder this is a
problem that often requires turning down the insert to a looser tolerance. For a non folder, a tight fit is ok as long as you don't plan
to take the frame apart at a later date.

Quote:
From the Dyson book Baidarka and from the Baidarka Mailing list archive
is would appear that this is held in place with an epoxy (West Systems?)
or by crimping the tube with a hole punch or modified tube cutter.
(Rivets or screws are another method).


Epoxy will work ok, as will rivets. I prefer rivets , even for a non folder, as it allows the tubes to be disassembled later if need be.
This will apply in the event of a bent tube replacement, or if you decide to reuse the tubes on a new boat.... I've done this many times.

[quote]I have been warned that the variations in the manufacture of the tubes may be
enough that I would have to physically check that the inserts will fit inside the large tube.[quote]

I've never encountered this as the various manufacturer's tubing I've used over the years have always met exacting standards.

Regards, Tom

PS - Rita and I had the Sonnet Double out yesterday in 37F water (See pic). Very cold !! On this boat the keel is 1" tubing that
tapers to 7/8" and 3/4" at the stems. The chine stringers are 3/4" with 6"X 5/8" inserts.

For the assistance, you owe me a couple pots of VB :D

Regards, Tom

A cold evening on the water....
Image

You can't make them simple enough or light enough to please me :)
Image

Just add water.... 37lbs of fun !
Image


Last edited by Yostwerks on Sun Nov 22, 2009 3:03 am, edited 2 times in total.

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PostPosted: Sat Nov 21, 2009 5:39 pm 
Little to add to Tom's reply - he is an expert.
Quote:
I have been warned that the variations in the manufacture of the tubes may be
enough that I would have to physically check that the inserts will fit inside the large tube.

Again, Tom is right - this happens very seldom, if at all. I recall now when building a kayak "trolley", tubes with 1/8" OD increments fit well into one another, provided wall thickness was the same (don't remember now if it was 0.049 or 0.055 - it was one of common imperial specs here). Only once I've encountered a problem when 1/8" smaller OD insert was going very tight into larger tube - not totally impossible, but too tight if you want to to take it apart often; I attribute this to imperfections of the seam of the larger tube, and possibly - bend.

Epoxy works so perfect that you won't be able to take tubes apart later. Especially if you also have some rivets or tapping screws through both tubes - even when you remove the screw, the burr on the hole of the outer tube gets pulled a little into the inner tube, making it difficult to separate them (in combination with epoxy I would say - impossible).


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PostPosted: Sat Nov 21, 2009 8:17 pm 
Hello Tom, thanks for the reply.

I can get access to imperial sized 6061 T6 is Oz but mainly from aircraft suppliers
with aircraft type prices. They are charging $4.00 per foot for 0.75 and 0.50 tube,
I did find one supplier that was about $3.25 per foot but since they are 2,000km away
most of that would be eaten up with transport costs.

Currently it appears it would be cheaper to ship from the States than buy it here.

Thanks for the link to the manual, I will have to have a re-read as it might answer alot of my questions.

6063 T6 is a lot more common here but it is all metric as far as I can see but it is cheaper.
It would appear to be more corrosion resistant but not as strong and somewhat heavier
than 6061 T6 in the sizes we have here. I got the impression there is not huge difference
is building your design in either 6061 T6 or 6063 T6?

Happy to buy you a pot or two of VB Tom, any plans to be in Oz?

That's one lovely Lake you have there , a bit envious.
Our little duckpond/swamp has been dry for nearly 5 years, although we had 2 inches i nthe last three hours which will go some way to filling it.

Thanks again for your help.

Tim W


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PostPosted: Sun Nov 22, 2009 2:24 am 
Tim,

6061 or 6063... Imperial or Metric... whatever is readily available and less expensive will meet your needs just fine. You won't be able to tell
any difference between 35,000 psi or 40,000 psi tensile strength. I once made a non folder from 6061 T6 with .035 wall and it was plenty
strong while saving 6 pounds in frame weight vs .049 wall.

Unless you are set on aluminum, good old wood will be readily available, plenty strong, corrosion proof, less expensive and generally lighter
weight.... A combination that's hard to beat :wink:

A motorcycle / kayak tour of New Zealand is planned for 2010, but the additional flight across the Tasman Sea is unlikely.
I'll have to take a rain check on the VB.... Tom

An all wood frame Dyson 5.28 with sewn nylon skin coated with Neoprene and Hypalon ( Lake Dillon, Colorado )
Image


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PostPosted: Mon Nov 23, 2009 9:13 pm 
Hello Tom, thanks for the re assurance re: 6061 T6 versus 6063 T6 tensile strength.
It will be certainly cheaper to build in 6063 here. I hadn't thought that much about
substituting wood for the aluminum, being my first boat I'm just rather slavishly following
the plans etc. (it is in the back of my mind that I would be better off build a Nikumi 19
as a first boat, we will see how my hunt for materials goes.)

I can see by the picture you have attached a timber framed Dyson 5.28 is still a very nice boat.
I see you modified the bow? It looks like quite a small boat looking at the plans.

New Zealand is a wonderful destination, if I could only visit one country it would be the one.

Had a nice paddle at Milford Sound, despite the clatter of aircraft and big tourist boats.
The other sounds (Dusky, Doubtful etc) are more secluded but a bit of a problem to get to.

A trip across the South Island from Christchurch to Greymouth would be fantastic by bike or train
as would from Christchurch to Kaikoura.

Have a great time.

Tim.

PS. VB on hold


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PostPosted: Tue Nov 24, 2009 10:07 am 
Quote:
I hadn't thought that much about
substituting wood for the aluminum, being my first boat I'm just rather slavishly following
the plans etc. (it is in the back of my mind that I would be better off build a Nikumi 19
as a first boat, we will see how my hunt for materials goes.)


There's nothing wrong with just following the plans.... Being essentially a lazy builder, I opted to build my first
Dyson with aluminum stringers and plywood cross sections as I didn't want to work with sheet metal at the stems nor did I
want to spend the money for a Holsclaw tube bender to form the aluminum cross sections.

Quote:
I can see by the picture you have attached a timber framed Dyson 5.28 is still a very nice boat.
I see you modified the bow? It looks like quite a small boat looking at the plans.


The Dyson 5.28 single is a fairly high volume hull design, though fairly shallow at the deck . I had some redwood left over from a
woodstrip build, so I used it to build this particular Dyson. I made a few changes to increase storage capacity. To do so, I raised the
gunwales 1" and then added an additional 1" to the deckridge height. At the front, I omitted the bifid bow shape in favor of a much simpler
closed / rounded shape. None the less, it's still a Dyson , and a very good design.

Quote:
New Zealand is a wonderful destination, if I could only visit one country it would be the one.


Agreed.... though , If I could change but one New Zealand feature, it would be the total extermination of those pesky sand flies in
Fiordland :lol: I don't know if VB is exported to NZ, so we'll likely make do with some Speight's Old Dark. I can almost taste the mince pie.

Cheers, Tom


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PostPosted: Wed Jan 20, 2010 6:19 am 
Hello Tom, I can understand why you added extra height to the front deck as it is pretty shallow.
I doubt my big feet would fit under the deck comfortably.

Did you increase the profile of the bow and stern sections to make up for the increase in gunwales height
or did you just taper them into the sections as per the plan?

I was thinking of raising the front lip of the cockpit and tapering the deck ridge up to it.

Most Baidarka's seem to suit 6 foot paddlers weighing around 82 kilos whereas I'm 6 foot 2 inches
and 91 kilos which makes it a bit of a squeeze.

Tim


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PostPosted: Wed Jan 20, 2010 11:50 am 
Quote:
Did you increase the profile of the bow and stern sections to make up for the increase in gunwales height
or did you just taper them into the sections as per the plan?


It's been so long ago, that I don't recall how I handled this. Most likely, I retained the same width / profile as the plans dictate
to insure a clean gunwale line. I've done it both ways on my own designs as I have the benefit of CAD to view the results of
any changes.

On a multi-chine, the angle from chine 3 to the gunwale is already farly steep, the distance between the two is fairly short, and generally
above waterline. Retaining the original gunwale width / profile results in little change, as does going wider for that matter.... Now you see
why I can't recall what I did :lol:

On my Greenland single-chine kayaks which have a greater chine to gunwale angle, a greater distance between the two, and some of it
below waterline , changing the angle has a greater effect on stability / handling. if I feel the need to increase the height for greater
volume / larger paddlers , why not then increase the width as well rather than steepen the angle ( same width as before) , which might
result in somewhat less stability and other handling differences.

An inch increase in gunwale height, usually equates to about an inch increase in width on a narrow / shallow single-chine design.

Could you repeat the question :roll:

Tom


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PostPosted: Wed Jan 20, 2010 7:19 pm 
Hello Tom, thanks for the reply.

The same question, asked slightly differently.

To get the extra height at the gunwales I understand that you simply added and extra inch of height to each "frame"
which at this point is close to vertical and well above the water line?

This would move the bow and stern blocks and inch "away" from the keel, did you make the blocks deeper or just
taper the keel up to the "higher" position.

Tim


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PostPosted: Thu Jan 21, 2010 10:27 am 
Quote:
To get the extra height at the gunwales I understand that you simply added and extra inch of height to each "frame"
which at this point is close to vertical and well above the water line?


You are correct sir !

Quote:
This would move the bow and stern blocks and inch "away" from the keel, did you make the blocks deeper or just
taper the keel up to the "higher" position.


I'm not sure what you are asking ... What do you mean by blocks ?

Tom


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PostPosted: Sun Jan 24, 2010 4:06 am 
Hello Tom, as per email.

Sorry for the slow response, laided low by an extremely high temperature.

Poor terminology on my part, I should have said stem plate and tern plate.

Thanks for your help.

Tim.

PS. On your Dyson single the rudder does not appear to be the same as the plans, did you fabricate one or is it an off the shelf item?


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PostPosted: Sun Jan 24, 2010 11:53 am 
Quote:
... On your Dyson single the rudder does not appear to be the same as the plans, did you fabricate one or is it an off the shelf item?


Regarding stem plates, just make them to match the gunwales and / or the taper of the deckridge... whichever is taller.

Below are several pics showing the rudder attachment on my boat's. The Dyson's rudder is a "Feathercraft", with the rudder post slipping
into the stern tube. This technique will work for many other commercial rudders as well. The frame pics show a simple way to build / bend
a Baidarka stern. This is a single chine, but a multi-chine is done the same way. Note the stern tube opening for the rudder post.

Rudder attacment... FAP 16 folder. ( non-feathercraft rudder)
Image

Feathercraft Rudder.... Dyson Single
Image

Feathercraft Rudder.... Dyson Single
Image

Tiller bar .... Dyson Single ( bolt goes through the deckridge)
Image

Bent stern / gunwale .... FAP 15 folder
Image

Bent stern / gunwale .... FAP 15 folder
Image

Sewing the polyester skin .... FAP 15 folder... Later coated with neoprene and hypalon.
Image


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PostPosted: Wed Jan 27, 2010 6:43 pm 
Thanks for the pictures Tom.

Make things alot clearer.

I had come up with a fairly complicated rudder peddle arrangement but I'm tempted
to copy what you've done. Simple is best.

Tim W


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