Hi Made in the USSR,
Looks like a Struer manufactured C1 (or is it a C2). The older boats are too wide (too much beam).
Basically what is needed
1/ Narrower beam at the widest point
2/ Minimum distortion of bottom shape.
From the top the boat is diamond shaped - this is so the maximum width is the same as the old rule.
The rule has changed. Now the boats can be narrower.
It is not necessary to use water to change the shape of the boat. The boat skin is very flexible.
This is what I would suggest to match items 1 and 2 above.
IT IS A RISKY PROCEDURE AND THE BOAT MAY NOT HAVE ANY VALUE AFTER
a/ Prepare
Attach a carefully shaped piece of timber along the middle of the bottom as shown in the top drawing attached below - this is so the rocker doesn't change. Rocker is the curve along the bottom of the boat.
The timber needs only be 20mm wide and probably 120mm deep.
Cut a curve along one edge of the timber that is the same as the curve of the rocker. It must be a very smooth curve with no bumps.
If you are working on the boat that has been soaked with water - use one of the other old boats to create the curve in the piece of timber.
Drill holes through the bottom of the boat along the centre about 400 mm apart.
Screw through the boat using 5mm diameter round headed screws with flat washers underneath their heads.
NOW THE ROCKER CANNOT CHANGE.
b/ Change width
To change the width of the boat you will need to cut a "V" shape out of the side like the top picture. I don't know what shape or length the cut will be. Go slowly. The two sides of the cut will have to meet perfectly when the side of the boat is pushed in.
To get the length of the cut have a careful look at the apex of the side of the boat. At deck level it is very sharp. As you move down the side of the boat it becomes softer. See where it disappears. The bottom end of the V will be near that point.
You will have to remove the timber at the top of the cut that holds the side skin of the boat in its original place. It is best to remove it then make new parts later. To allow enough flexibility it should be removed
To make sure the sides of the boat remain in a smooth curve you will have to use a batten which will curve evenly. A batten to suit this purpose will probably have to be approximately 20mm x 15mm by 2.5 metres long. you will need two - one for each side and one more to cut into smaller pieces.
Cut the "V slowly and carefully.
when you have it to the correct beam screw the battens in place. Screws must be more than 60mm away from the V. Perhaps you will have to use 6 screws for each batten. If the batten is too stiff you may have to reduce its cross section.
Put a string down the middle of the boat (on the top) to make sure it is the same on both sides.
Carefully check the V.
At the top it should be a smooth curve. Lower down it might not have a smooth curve from one side of the join to the other. If this happens cut the 3rd piece of batten into pieces about 600mm long. Screw them in place across the V. Screws must be a minimum of 60 mm away from the V.
As the screws get tighter and push the sides of the V together you may have to remove more timber from the V.
c/ Joining across the V on the inside
You will use fibreglass tape on the inside and outside of the boat to make the join permanent.
Remove all paint and varnish from near the V. The bare timber should be exposed for 50mm either side of the V and for 50mm below.
Put two layers of fiberglass tape on the inside the full length of the V plus about 25mm. First layer can be 50mm wide fiberglass tape. Second layer is to be 75mm wide glass tape. USE EPOXY TO SATURATE THE TAPE SO IT GOES CLEAR. The surface will look rough - wait for the epoxy to go tacky (NOT FULLY CURED) and put on a thin second coat. When that second is tacky put on a third coat. Now the roughness of the fabric should be less.
d/ Remake the inside structure that was removed
Decks and ends and structure across the VEE has to go back in the boat or be remade. DONT REMOVE ANY OF THE BATTENS FROM THE OUTSIDE - THE REPAIR IS NOT STRONG UNTIL THE OUTSIDE IS GLASSED.
You can remove the two top battens once the inside structure is back
e/ Fibreglass the outside of the hull
First all the battens on the outside of the hull need to be moved inside.
Remove one and screw it inside the hull. - use the existing screw holes that are in the hull.
Remove another and screw it inside the hull.
Remove the varnish or paint from outside of the hull. Same method as inside. Use sandpaper wrapped around a block to make the outside very smooth across the V.
Apply one layer of 75mm wide fibreglass tape on the outside. Apply additional coats until the weave of the glass is full.
f/ sanding the fibreglass ready for painting/varnish.
Remove the battens from the inside of the boat.
Fill the screw holes with a paste made from epoxy and wood dust.
The fibreglass need to be made smooth and flat.
It is important not to damage the fibreglass on the outside of the boat where it is over the V. Sand it lightly and carefully by hand. Then you can use a vibrating sander to smooth down the edges of the fibreglass.
The wood will be damaged easily. Keep the sander over the fibreglass and use the edge of the sander on the edge of the fibreglass.
When smooth enough paint or varnish according to the paint manufacturer's directions.
Remove the timber along the bottom of the boat and fill the screw holes.
g/ See how the boat works
This is where my advice leaves you. All the changes might result in a good boat - or they might not.
I would be grateful to hear news of the procedure and result.
[email protected]
Good Luck
Michael Storer
Michael Storer Boat Design