37 replies to this topic

[Kudzu]

As of 1 PM my Long Shot has been decommissioned. My favoritie boat has developed a really bad habit, it now leaks! Not enough to be dangerous but enough I don't feel comfortable paddling it. I mean the water is cold on my legs and I REALLY don't feel comfortable!
 
This is a photo of her on her last voyage today.
 

 
Not 100% sure why the leak but there are a couple of possibilities. I painted this boat with latex paint (never again) and it has scrubbed off, down to fabric in a lot of spots on the bottom.  Found a really good scrap on the side about the water line, so any or all of those could be seeping water. Or it could be the mysterious small cut in the fabric under the keel. 
 
Regardless I have been thinking about modifying this boat yet again for a few months now. I think this will be third or fourth time I have modified her. It was the prototype for the Long Shot and has been a test bed for ideas ever since it was built. One thing I have never been happy with is, is the frame is too flexible. I used to stringers that were to small on it. I specified larger stringers on the plans which stiffened it up considerably. I have always wanted to fix that but it a pretty big job. I have something new I want to try and this is a good time to try it.
 
Plus I recently had a frame crack and it needs to be replaced. The coaming is looking really shabby from all the exposure it has had. So there are a lot of reasons to retire her. She has a lot of miles on her!
 
I have wanted a Baidarka and I have never built myself one. I have so many boats I really hate to build another one for melf. I have been thinking that I could convert Long Shot to a Baidarka. I have been working on the design for a while now. I am very close to finishing the design. so I think Long Shot is going to be a Baidarka this winter.
 
Long Shot is dead * Long live Long Shot!

[woodman]

So.. Jeff ....has this been the boat you have put more time in than all you're other designs?

[Kudzu]

Yes. It is my go-to boat. By far my favorite. There is just not much I don't like about that boat. It fits me really well and I find it more comfortable than any of the others for a long day or paddling. 

[Kudzu]

Proposed changes. Not quite happy with the stern shape but I am getting close.

 

[Chris Martin]

There are a lot of different baidarka bows but I have always been partial to the one in John Brand's book 1984.

 

I like the look and it seems it might be little stronger if you run into something.

 

[woodman]

How about this softer lines..more of an hour glass shape.....

 tn_100_3131.JPG   32.35K   11 downloads

[P Douglass (WA)]

There are a lot of different baidarka bows but I have always been partial to the one in John Brand's book 1984.

 

I like the look and it seems it might be little stronger if you run into something.

 

 

 

How would you stitch around that??

[Chris Martin]

Corey Freedman from the Skin Boat School

 

http://www.skinboats.org/

 

has 10 Youtube clips on the progression for sewing.

 

The whole series is about 18 min total.

 

The link below is for clip 1 in the series.

 

 

I am no expert but it is what I hope to follow.

[Kudzu]

NEVER start sewing on the top. NEVER! I learned that lesson the hard way. 

 

I am still playing around with ideas. I have so many boats there is not rush to start on this one.

[Chris Martin]

Jeff,

 

Was there something in the Youtube clips that stuck out that you would not do?

 

Not clear on your comment about do not start on top.

 

From what I can see the baidarka is upside down, they do part of the bow, mark for stern stretch, hook the stern and  then flip it over and work from top middle out to the ends.

[DURRETTD]

The Baidarka bow looks exotic and interesting and I'm sure the Aleuts developed it for a good reason. Does anyone have a clue what that reason was?

[Chris Martin]

Some of the early discussions of this appear in the following which has works by John Brandt and George Dyson

 

Contributions to Kayak Studies (Canadian Museum of Civilization Mercury Series), 1992

• Paperback: 347 pages
• Publisher: Canadian Museum Of Civilization (January 1992)
• Language: English
• ISBN-10: 0660129132
• ISBN-13: 978-0660129136

Some reasons that are discussed are:

 

1. The lower jaw inceases the actual waterline length of the kayak. Greenland Kayaks have long pointed ends but the legnth that actually counts is the amount of the kayak in the water.

 

2. The upper jaw if you look at the picture by John Brandt is triangular in cross section which adds to flare which helps the bow not get buried in waves.

[Kudzu]

Started dismantling the boat and seeing what I was up against. I removed all the hardware and fittings. Then I cut the skin open and peeled it open like a banana.

 

 

The frame looked just as I expected. (The white on the frame is not mold, it's paint that soaked through) It was in good shape with only one big surprise. One of the reasons for the reskin was I was seeing some flexing in the frame at the front of the coaming so I knew the frame was going to need to be replaced at some point. When I got skin off I was VERY surprised to see this.

 

 

 

Even though the frame was in two pieces,  the skin and the lashing were holding together quite well so and there was no way to see it was actually broken in two pieces  There was no danger because the skin wouldn’t allow it come part. My only hint there was a problem was it flexed when I tied it down on the car. 

 

What happened, why did it break? I don’t know but when I strap it the rack on my car, the straps fall right on top of this frame. On my trailer the straps are further toward the ends.Another thing is the frame was very thin under the deck stringer. It’s also likely the plywood was weak. This was Douglas Fir and not very good quality. I quit using this ply right after this boat was built because I was getting worse every time I bought it. The more I have looked at the boat the more I am leaning toward poor quality plywood is the biggest reason.

 

The frame design was changed after I paddled this one. The new ones are beefier so they would be stronger, especially if you use Baltic Birch plywood. This was my prototype and as I said, I this was one of several changes that have been made to improve it.

 

Oh yea, I found one other surprise inside the boat. There was the usual dirt, bugs and misc. trash that get trapped in the ends. But this one I was not expecting! Created some scary thoughts in my mind too.

 

 

 

[Hirilonde]

What happened, why did it break? I don’t know but when I strap it the rack on my car, the straps fall right on top of this frame. On my trailer the straps are further toward the ends.Another thing is the frame was very thin under the deck stringer. It’s also likely the plywood was weak. This was Douglas Fir and not very good quality. I quit using this ply right after this boat was built because I was getting worse every time I bought it. The more I have looked at the boat the more I am leaning toward poor quality plywood is the biggest reason.

 

I can't comment as to the design of the frame, or whether there was enough material around the notch, but that plywood sure looks like junk compared to Baltic Birch, BS 1088 or AS 2272.

[Kudzu]

I now have the frames cut out and wrestled into place on the boat. They are not that hard to replace but they sure don’t fall into place. It took some 'gentle' persuading with a wood mallet to convince them. But once you get them close they will then fall into place. I have started lashing but I just did enough joints to lock them in place.

 

 

Here is the bow sort of in place. I wanted to see what I had and what I needed to do to fit it in place. I want to build up the bow by gluing on some wood and then shaping it to get the proper look. This is going to take some time to get right.

 

 

The stern I am extremely happy with. I have been through a lot of ideas before I finally settled on this one. I wanted something fairly traditional but at the same time I didn't just want to copy what has always been done. I took ideas from two or three different boats and this is what I settled on. Now that I see it on the boat, I really like the way it looks. It looks better than it did on the drawings.

 

[James Miller]

As to the reason for the shape of the ends of the Baidarca, I'm no expert, but I've seen illustrations showing another paddler taking hold of the end of an inverted boat to assist in the recovery, so I thought that the end design provides an easier grip on the boat, remember, they were oiled for water proofing. Several other Alaskan kayaks are similar to this idea. I really like the simple grace of your origional profile. Also I am more of an empirical builder than a trained architect. I would have to sit in a floating hull to get the exact position of a cockpit rim. Hope to build a skin boat some day of my own design and mold off it for ultra light laminated boat.I've seen that a multi chine hull can be built very light in a mold as the chines act as stringers and the skin between can be one or two layers of the right material. How about a 12 foot, 40# dory for an example! If my white water building experience is any example (aprox. 90 boats) I could build two boats a week in about 40 hrs., or less with the simpler lam. schedule. But I'm retired sort of, I'm just sayin'.

[Kudzu]

Just a quick post. I spent a lot of time working on the bow but there is not a lot so see. I wanted more than just the flat bow stem. I wanted to add some shape to it so it didn’t just look like a piece of covered plywood.

 

 

My first step was fitting the bow in place.  Clamped  in place I decided how I wanted to install it and the details of how I was going to do this. Once everything was trimmed and fitted it was time to move to the bench.

 

Since I am not working with a big block of wood I need to add stock. I started with a lot of scraps of cedar on my bench. Left over pieces of stringer, cutoff of’s from paddles, etc. I tossed around a lot of ideas trying to decide how best to get the look I wanted. After a lot of different ideas I decided using plywood  was the simplest way. It is heavier but it is also stronger and simple to glue in place since it has smooth faces it ready to glue in place.

 

 

Tracing the outline of the bow on the scrap plywood, I cut the pieces on the bandsaw.

 

Holding them in place I stretch an old piece of t-shirt over the bow, this shows me how it will look once skinned. It also shows me where the skin will touch and where it doesn’t and how it transitions from one section to another.

 

I have to do a lot of trimming and shaping with the rasp to get the proper look and keep from  having a boat full of bumps and flaws.  It’s a slow process but if you don’t it’s very obvious and very ugly to my eye.

 

Once I was happy with the look, I applied the glue, clamped everything in place and called it night. This afternoon I still have a little fitting to do but I expect to finish the fitting the bow and start lashing it all in place.

[Kudzu]

I finished the bow and started lashing all the joints I had left loose. For some reason the stringer slot in this frame is deeper on the new design than on this one. If I lashed the joint it would pull the stringer out of line. If I had some wedge shape cutoffs from cutting scarfs lying around I could shim the slot to fit. But since I didn't and they are lashed to the near by frame I decided to just leave like this.
 

 
 
While I am lashing I look down and realize I am being watched. Then I realize 'I' am not being watched, it's the lashing that she is watching. She could care less about me, see the dangling sinew? She does.
 

 
I turn my back to cut another length of sinew and I hear wood banging around. I turn around to find Grace inspecting my lashing and knocking the floor stringers out of the boat. All this time she has shown no interest in the boat. Now she won't stay away.
 

 
Despite all of Grace's help I did manage to finish the frame. It is ready for to be oiled and skinned. Except I have some slightly different plans. I am going to order some red dye to color the frame. Then I will apply the oil finish over the dye.
Somewhere I read that many/most/all Baidarka frames were red. So, I am going to dye it red. I have always like the idea of the frame being a contrasting color but I have just never followed through on the idea. Maybe a black frame with a white skinned boat? Or a red frame with a ....... no,  you will have to wait to see what I have in mind for the paint job. It's a surprise.
 

 
I am going to try to do something to stiffen the frame too. As I have said, this frame was the prototype Long Shot and I made changes to the final design. One thing I was not happy with is that this frame has always been too flexible  All Fuselage frames flex some, but this one was very flexible.
 
Since it is apart, I want to try reinforcing this frame with Kevlar roving similar to what Plat did on his Geodesic boats and see if that will not stiffen it. If it works I could see it having applications on a fuselage frame race boat.
 
If you are serious into racing you do not want any flex in the boats hull. While it is probably slight, the energy spent flexing the boat is energy not moving the boat forward. Probably very minimal but races are often won by very small amounts.
 
I have to order supplies so it will be next week before I can do much else on the frame. So mean time I am going to try to get some work done on the Sea Skiff.

[Kudzu]

Today I was finally able to get back to work on Long Shot. First work got very busy and I was so tired that I just didn’t feel like working. I should have recognized that as a warning. I have been through this so many times!  I was coming down with a sinus infection and for almost 2 weeks  I barely felt like getting up and fixing something to eat, much less going to the shop to work.
 
As I mentioned, this boat was a prototype and the frame was very flexible.I have wanted to do something to stiffen the frame for a long time. I decided to try the Geodesic Boat method of using Kevlar roving wrapped around the frame. Platt’s boat frames were so extremely light he used the Kevlar to give them enough structural strength not to collapse. OK, I don’t know that they would have collapsed but I strongly suspect some of his designs would have failed without it.  He took light weight to the extreme!
 
This morning I started with the Heat n Bond tape and ironed it onto the frame along the gunwale and the keel. I tied off the Kevlar to the frame and started wrapping it around the boat and then clamped the end to the frame. Starting at the front I pulled the Kevlar tight working toward the cockpit. Once the roving was tight all the way down the boat I secured the end.
 

Using my heat gun to warm the tape where the Kevlar crossed I took a dowel with the end rounded over and pushed it into the tape to ensure a good bond.  Latter I found out that it was easier and quicker to just use the iron with some of the paper backing between the iron and roving. This kept glue from getting on the iron.
 
After giving the tape time to cool, I removed the clamp and was impressed with how well the tape held the Kevlar. I could lift it up without a lot of effort, but in tension the grip was strong that this where the stress is.
 

I started on the bow wrapping the roving around the boat.  I now realize I was spacing it way to close together. On the rear of the boat I used a much bigger spacing and it is just as stiff and it was much faster to apply. And it looks much better.

I kept testing the frame by flexing it and at first I was disappointed. There just didn’t seem to much improvement. But once I got everything in place I could tell that the frame was much stiffer than before. Not stiff like a plastic boat but miles ahead of where it was. 


When I put the skin on I am going to pull it tight and bond it to the tape with the iron before sewing. Once the skin is shrunk I am very confident that this boat will be at least as stiff as the rest of my designs and I will be a bit surprises if it is stiffer. Either way it will much improved over what it was.

[Ted]

Jeff, which flex are you trying to minimize: lateral or longitudinal (or both)? Your pictures seem to show the kevlar roving is almost vertical on the sides and angled on the deck and bottom portions. I believe that maximum reinforcement is when the kevlar is triangulated. In looking at the tech view of the Montford "Rob Roy 14", the kevlar seems to be attached at the keel and gunwales and is at an angle of about 60 degrees from horizontal. The last picture in their photos section seems to show this, also. I can not see how the roving is attached to the deck beam, but it would be easiest and best to continue a straight line from keel to deck beam.

 

All this is based on the triangle being the strongest two-dimensional shape, but there may be other considerations in actual constructions. Does this make sense?