Exprnc Bldgng Baidarka

Thoughts on Building the Baidarka




  1. Thoughts on Building the Baidarka
    1. Plans
    2. Transfer of Plans
    3. Building Jig
    4. Cutting Out/Drilling Pieces
    5. Assembling Pieces
    6. Assembling Stringers/Frames
    7. Attaching the Skin


Subj: Exprnc Bldgng Baidarka...part 1 of
Date: Sat, Feb 11, 1995 6:01 PM EST
From: MRPK81A@prodigy.com
X-From: MRPK81A@prodigy.com (MR TOM L CLARKE)
To: baidarka@imagelan.com

Thoughts on Building the Baidarka

Following are a bunch of thoughts about building the 5.28 m Baidarka from the bluprints and kit materials supplied by Geo. Dyson... they are given in the order of building... they reflect what I learned... what worked, what didnt, as well as some suggestions for making it easier for the next person... I hope this material will be useful....Tom Clarke... January 31, 1995

Plans

For the frame support molds, I drew in two 1/2 inch holes for each support, to replace the single alignment hole in the plans... I made them 6 inches apart and at the same height as the given alignment hole... for frame supports 1 and 9, I made the hole 1/4 inch (half the hole diameter) higher... (See Building Jig below for how these were used).

I spent a lot of time aligning the three sections of the cockpit coaming on the aluminum sheet... It would be really helpful if there were a straight line on the plans which intersected the two joints... This would enable the three pieces to be aligned perfectly when laying them out on the aluminum...

I used a single knee for attaching each deck beam to the frame... I picked these off of the blueprints... They worked well...Didnt do it for any other reason than it seemed like a good idea at the time...

I have not had the boat out yet, so this is from a purely cognitive view, as opposed from a experience view... I am concerned that the rudder (the new version, in which the depth is to the bottom of the keel) will stall at a very slight angle of attack... very low aspect ratio, similar to the barn door rudders on cat boats... such low aspect rudders are helped significantly if a foot (spoiler plate) in placed on the bottom... Phil Bolger has had a lot of positive experience with these... Im going to try it as designed, but will build another with a foot, probably 1.5 inches wide and running the full length of the rudder, if this one stalls at the angles needed....

I am 62... My knee caps are just aft of frame 5, with my back within an inch of the aft end of the coaming... Bottom line, I fit, but just barely... If I were to build another, Id move that frame forward an inch and also raise the forward end of the cockpit a half inch...

Transfer of Plans

To transfer the frame supports to plywood (I used 1/4 inch plywood and it worked fine), I placed the plywood under the blue prints and used an awl to transfer the center point of all holes and the base line... marked the size of each hole on the plywood... I also drew in vertical and horizontal line (each about an inch long) centered on each alignment hole (see above) Drilled the holes, drew in the baseline on the plywood, then cut each frame support, running down the middle of the line of holes for the stringers, and about two inches below the base line... I also ran a saw cut from the center of each alignment hole (see above) at a perpendicular to the bottom of the support down to the bottom...

For all aluminum parts, I cut out the blue prints and wall paper pasted (vinyl paste... left over from doing the nursery for our grand-daughter) the blue prints directly to the aluminum sheet... This worked well, and the blueprints washed off with water after all the sawing and drilling...

Building Jig

I built the jig using 4 ten foot 2X4s...two for each side of the ladder, with a two foot overlap, giving me 18 feet. After nailing the two sides up, I clamped them together and drew in a line for each station across the two sides. I then separated the two sides and nailed in 9 2X4 (X15 inch) braces across the top of the two sides... aligning the edge of the cross brace 1/8 of an inch from the line (I used 1/4 inch plywood frame supports)... The sides of the ladder frame were on edge (i.e., 4 inches high), while the cross braces were nailed flat... I then squared up the ladder frame and nailed in two pieces of plywood, about 12 inches by 15 inches at each end of the ladder frame to lock it so that it would not rack out of alignment...

I then nailed number 1 and number 9 frame support to the corresponding cross brace, making sure that the base line from the blueprint was aligned to the top of the cross brace, and centered on the cross piece... I then ran two pieces of line (squid line, pulled very tight) through the horizontal center of the alignment holes and resting on the bottom of the holes... I tied them off to some nails in the plywood braces at the end of the ladder frame to prevent the 1/4 inch frame supports from bending...

Then I took each frame support, slid it over the two lines and nailed it to the ladder cross brace such that the line bisected the alignment hole vertically and horizontally... note that the alignment holes for support 1 and 9 are a half-hole higher that all others...

This system worked very well... I didnt have to build a rigid bench... I could always check alignment, even after tripping over the partially completed frame and knocking it out of alignment... all I had to do was kick it back in place to make sure all frames were centered on the two lines...

I kept the frame on the floor the whole time... (I was really cramped for space and couldnt have built it at normal height even if I wanted to...) Worked fine... no problems...

Cutting Out/Drilling Pieces

I used a band saw for most cutting of the aluminum sheet... I bought an 18 tooth 1/4 inch blade, but found that a standard 10 tooth 1/4 inch blade worked just as well...

For cutting the lightening holes in the stem and stern, I drilled a 3/8 hole and used a saber saw... the saber saw would not turn in a tight enough radius (used a Skil saber saw with a 1/4 inch hack saw blade)... so I ended up making radial (straight) cuts from my original hole out to the edge, about every 1/4 inch or so, then cutting off each little pie piece as close to the edge as possible... I then used the two rat tail files (3/4 inch and 1/2 inch) to go out to the edge... a very noisy but quick process...



I used a drill press for drilling all holes, then again for countersinking... Used a larger drill bit (not a counter sink bit) to counter sink, carefully setting the depth of cut with the drill press... no problems other than boredom.

The deburring tool is wonderful...I also made heavy use of a couple of flat mill files to take off all of the band saw blade marks on the edge of the pieces... (I know that no one will ever see them, but I know they are nice and smooth)...

Assembling Pieces

I used doubled squid line (what you supplied) for all lashings... I experimented with a number of knots and bends and came up with the following, which worked:

Started every lashing with a Packers Knot...Tie a loose figure eight knot in the end of the doubled line. (The other end of the doubled line is the middle of the single line with the needle threaded on it). Pass the needle end around the piece which will be the anchor piece, then up through the loop of the figure eight knot which has the bitter ends coming out... and parallel to those bitter ends.... tighten up the figure eight knot, cut off the bitter ends within an eighth, seal them with flame, then draw the knot up tight against the anchor piece... It wont slip. Now continue with the normal Scout lashing (or sewing... I used the same starting point for all sewing and lashing)

Ended each lashing with a round turn, then three clove hitches... cut off the end, sealed with flame...

The only bend (for tying two lines together) I found which did not slip was the Fishermens Bend... I ended up only using it once... Rather than bend one line to the last (for example, when doing long sewing runs on the bow or stern) I just tied off the end of the line with the clove hitch and started the next set of holes with the Packers Knot...

As noted above, I used single knees for deck to frame joints... Pain to cut the groves in the tubes for the single knee to fit into... I used a hand hack saw as far as I could cut, then the edge of a 4 inch mill file... Held the tubing with two wood blocks with a deep V grove in each block... I could hold it tight in the vice without collapsing the tubes...about half way through the frames, I started doubting the sanity of using single knees rather than the double knees you show...

As noted above in plans, if I were to do it again, I would have held off on finishing (i.e., not cutting to length according to the blueprints) frame number 4.5 and 5 until after all other frames, the cockpit rim (not coaming), foot braces and stringers had been put in... Then I would have been able to adjust the height of the front of the coaming and moved 5 forward a little to adjust to my body...

Another it seemed like a good idea at the time item... although this one worked out very well... (but again tried my patience) Since the inside of the coaming is exposed, I thought it would look nice if it were machined (Im not sure that is the right term). After a lot of experimenting, a glued a piece of closed cell foam, a 1/4 inch thick, to the end of a 5/8 dowel (used rubber cement)... then in turn glued a small (5/8 inch diameter) piece of 600 wet/dry sandpaper to the foam (again, with rubber cement)... put the dowel in the drill press. Took a piece of plank (6 X 8 inches) and put two 4 penny nails in the flat of the plank close to the top edge, exactly 3 centimeters apart (all holes in the edge of the coaming are 1 centimeter apart)... I clipped the top of the nails so there were two spikes sticking up about an eighth of an inch... clamped the plank on the drill press so that the center of the abrasive was lined up with the line between the two spikes and equal distance from them... I now had a jig in which I could put a swirl every centimeter, parallel to the top edge of the coaming... after each row, I re-clamped the board 1 centimeter further away from me...The wet/dry paper was used dry and lasted for the whole coaming, as did the rubber cement!...end result is a beautifully machined coaming...


Assembling Stringers/Frames

Had some trouble at first joining the three sections of tubing for each stringer, but finally found the following worked well... filed smooth the splicing sleeves and the inside edge of the two stringers to be joined... Vice Gripped the sleeve tight so that the saw kerf you put in was squeezed tight, then drove it into one stringer with a wooden mallet... Vice Gripped the other end of the sleeve and started it, with hand pressure into the joining stringer... I then picked up the whole assembly and drove it into a nice handy 2X8 as if I were throwing a spear... This drove the two pieces together without bashing up the next end.



I attached each stringer to the frame supports with a single piece of squid line... line comes from forward, through the hole (under where the stringer sets), up over the stringer, back through the hole, up over the stringer a second time, back through the hole to the next frame support... tightening up as I went... This held the stringers in place, but kept the line out of the way of the frames and lashings that would come later... (When I did the lashing, some times Id catch the line holding the stringer down... not a problem, the line came out, when I pulled the frame from the building jig, without any problems)...

I put in the keel, stringer I and II, then attached the bow and stern assemblies, then all the frames, then the rest of the stringers...

The gunwales did not fair to frames 4, 4.5 or 5 (I think there were three places out of the six that did not hit right)... I made spacers out of spare tubing (about a centimeter long and 1/3 circumference) and lashed these in to have a fair curve on the gunwales...

While assembling framework, I continually checked the alignment holes on the frame supports and that each frame was vertical, etc. etc... a lot of minor sliding of lashings to get this all aligned perfectly...

I used a plate of aluminum for the base of the Henderson pump, placed on the starboard side, about 12 inches aft of the cockpit... plate lashed to the top of the gunwale and the deck stringer....



I screwed each 13 inch Yakima foot brace to a pair of bridges... each bridge is aluminum, about 4 inches long, and is a flattened U shape in cross section... the bridges are lashed to stringers II and III, one forward of frame 6, and one aft... the height of the U is such that the foot brace just clears the inside of frame 6... This set-up was required because of leg length... an inch shorter and I would not have had to bridge over frame 6...

Epoxy coating on all lashings and sewn assemblies was no problem... any drips that would hit the cloth covering were filed off smooth... Did the top of every lashing/sewn assembly while the frame was still in the building jig... then, after it dried, released it from the jig, turned it upside down, and did the bottom...

I used 1/4 inch varnished mahogany planks for the floor boards... they run from frame 5 to 6 only, lashed to the bottom of the frames... I did this to give me more foot room on the braces (Ive got size 12 feet)...The floor boards are only from the keel up to stringer I.... I also made a platform of cross planks, lashed to the top of stringer I, side to side, running from station 4 back to station 3... for junk... These planks made from 3/16 varnished mahogany, 3 inches side... a third lashing down the keel line holds the planks together...

The coaming is lashed to the cockpit rim with doubled line spiraling around the rim and through every hole... then a second time, but in reverse... this way there is a zig-zag pattern of doubled lines running between the bottom row of holes and the bottom edge of the coaming... I found the coaming was not the right length the first time... the holes did not match up in the overlap aft... I marked the overlap, pulled the whole thing off, cut it off at the overlap, drilled some new holes and resewed it with a butt joint... extra work, but looks good...

Attaching the Skin

Skin is the 15 oz. nylon... nice stuff... With frame upside down on two horses, I laid the cloth out and basted it to the two gunwales whole length... I placed it with about an inch overhang to the end of the keel... not enough. I found out the hard way when I was sewing up the stern... the last of the sewing... because the stern tucks in, the cloth was not long enough to reach the top of the transom... short by about a 1/4 inch after all the stretching I could do... ended up fishing a piece in... key is, leave about 3 inches at the end of the keel when first laying it on..

I started in the middle of the side of the cockpit, alternating sides about every 6 inches... with a lot of patience and pulling stitches out and redoing, got it around the cockpit without any wrinkles...I then went around a second time (all with single line, not doubled) so that on the inside of the coaming, there is a continuous line of stitches connecting the bottom row of holes...for aesthetic purposes only... it certainly did not need the second row for strength...

Since this nylon does not heat shrink like the other skin... at least that is my understanding... I wanted to set this up tight the first time... This is the technique I used...temporarily sew one edge to the deck beam firmly... mark the center line of the deck beam on the skin with a pencil... pull the other edge as tight as I can, marking the center of the deck beam on it... cut off on both pencil lines, plus an extra 1/8 inch or more, depending upon the humidity (if dry, use a scant 1/8 inch... if high humidity, use a very full 1/8... even a 1/4 inch... I had to play it by ear)... I then put a tick mark every centimeter...

I used a 40 watt Weller soldering iron to cut the cloth...filed the tip with two hollows on each side... worked great.

Sewed up through edge A at centimeter 1, down through the seam and up edge B at centimeter 2, down through the seam and up edge A at centimeter 3, etc... go for a foot or so... pulling the skin toward the bow (or stern) at the gunwales and at the keel...then do the other side....Up through edge B at centimeter 1, down through the seam and up edge A at centimeter 2, down through the seam and up edge B at centimeter 3, etc...

I should have been more careful doing my rough cuts at the bow... I cut a tad too much off and as a result, the crotch in the bow is not at deep (as far aft) as it should be... If I were to do it again, Id sew the deck to about station 9... then Id do the bottom of the crotch... then the top of the crotch at the same time as the deck, then finish off the horn... I probably spent more time on the forward 18 inches then the whole rest of the sewing...The end result, except for some patches noted below, is beautiful... on dry days, the whole skin is drum tight without a wrinkle... on damp days, it tends to sag some (note, this is without Hypalon)...

There were a few places were the 2 halves did not meet tight enough to be waterproof... for example, on the aft side of the horn... What I did was to cut out some strips of nylon, about 1.5 inches wide and glue them over the offending areas with rubber cement... I also sewed an additional reinforcement cloth over the top of the deck beam just aft of the cockpit were the paddle hits when getting in and out... This was the only time I used the curved needles, the flat stitch requires it... elsewhere I used only the straight needles, and only broke one...(Sewing it seemed like a good idea at the time, vs. gluing... It is more aesthetically pleasing when sewn) After I got the cloth all on, I found it a little difficult (but eventually OK) to get the cloth tight around the aft end of the keel.. I realized, too late, that one more hole in the vertical plate of the keel, located right were the aft end of the keel and the plate intersect would have made the job easier... I could have wrapped some line around the keel, through the hole and made it tight...

Nylon Belt Rubbing Strip I used two (4 oz.) cans of rubber cement to do this... with some other handy uses for the cement, Id recommend 3 cans per kayak... Rubber cement works at below freezing temperature... No change in working properties... To make the belt lie flat around the horn of the bow, I burned in cuts, about 3/8 deep, perpendicular to the edge, every 2 centimeters, on both sides of the belt, starting forward of station 9 when the bow starts to turn up... These cuts allowed the belt to lie flat on the curve... worked well... after it was glued on, I just took the soldering iron and smoothed out the edges...

Coaming Edge I sewed the nylon rope to the coaming with blind stitches...single threaded needle out through the coaming and through the rope, then back through the rope using the same hole(this way, the line is buried inside the rope and doesnt show except on the inside of the coaming)...Went around once, then a second time through the other set of holes... thus leaving a continuous line of stitches on the inside of the coaming... the second row is definitely needed... the rope is absolutely solid against the coaming and does not move at all... This technique did flatten the rope slightly, but did not affect the security of the spray skirt.

Bottom Line The end result is beautiful... exceeding my expectations in every way...highly recommended...


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