Sunday, 28 August 2016

Finishing the frame

Lashing the chine stringers
Grooves can be cut in the chine stringers to take the twine as any bump that ends up on the surface is much less likely to wear through as it is the keel that takes all of the wear from groundings etc.

The next two pictures shows the stringer being lashed to the frame. In the plywood frames such as this one the needle and thread is taken through one small hole. The second photo shows how the thread is secured through a series of half hitches. You can also see how I have rounded the stringer. This is to save a bit of weight and more importantly present a smooth surface fro the fabric to pull over.

I find it convenient to start the lashing of all the stringers from the stern and work forward.

This done the boat is turned over and the foredeck stringer pinned in place using the barbecue skewer pins again. The stringer is thickest near the cockpit to provide sufficient strength should a boat need to be hauled over the deck in a rescue.

 Similar principles apply to the stern deck stringers which also need to support the weight of the paddler behind the cockpit.
Then the seat goes in being lashed to the two central frames, positioned to take the ends of the seat slats, they are rounded off before being lashed and sewn in place as shown in the next three photographs.

The frame is shown awaiting adjustment of the masik, which needs to move back in line with the end of the bow deck stringer, and the footrest.


Saturday, 13 August 2016

Going back to go forward

Looking back at cutting, shaping and fitting the keel stringer
Suddenly realized that I had jumped ahead of myself in the last post and left out the keel stringer. This was cut to length and then planed fair as shown in the two photos below:



You can see in the picture above that the keelson was laminated from two pieces of 15mm square douglas fir as I wanted a strong keelson without a lot of depth to it. The taper at each end was cut from frame 1 to the end at the stern and frame 6 to the bow, marked on the keelson from the first trial fit. Because of its considerable width I did not drill through the keelson crosswise to take the lashings to the frames, and instead drilled four holes down from the base (the top in the picture) either side of each frame.

As a groove was cut to the outside of each hole (where you can see that a champher has been planed) the the thread should not project above the keelson. It is best to avoid any bumps on the keel where the fabric will wear through. This lashing was done after the keelson had been pinned and lashed to the bow and stern pieces.
Cutting, fairing and fitting the chine stringers
This largely follows the same sequence and methodology as for the keel stringer as shown below:

Trial fit to get the correct length and beginning points for the tapers, cutting the taper

Champher the stringers, accuracy coming from the use of a marking gauge in this case set at 3/16th inch.

After a second fit held with clamps the fit at the nose was cut with a handsaw in situ as shown below

After you have done a few you find that you can estimate the angle very accurately (I have pencilled in the angle for the photo but it is actually a distraction, my advice if you are doing this sort of work is to trust the eye and practice). Even if the fit is a bit off the is no structural weakness.

And the same at the stern
 Once the chine stringers are lashed in place the hull will be done and the boat turned the right way up for the deck stringers.

Friday, 12 August 2016

Bow & stern pieces

Fitting Stern piece
The outline was produced from a tracing onto cardboard from the plan, then trial fitted and adjustments made, and then used to make the ply piece shown below being given its trial fit against the stern frame:

As can be seen this needed a little taken off from the front of the piece abutting the frame and it fitted fine, this done the angle of the stringer was taken as it came across the stern frame:


And then transferred to the stern-piece so that the slot for the stringer could be cut: this was a retrospective photo to show how it was done after the slot had been cut. It is also possible to see a piece of cedar added to the piece to give a better curve after it had been faired.  
The whole thing fitted together as shown below:

You can also see the wooden pin that along with the lashing secures the keel stringer to the piece, the pegs that centre the stern piece into the end frame, and the lashing from the piece to the gunwales.



A similar process was applied to the bow piece. Next is how the stringers went on.

Thursday, 4 August 2016

Catching up with progress

Apologies for the delayed post due to my lap-top expiring.
All but one of the frames have been lashed in place alongside the deck beams, and the one in the centre (where there is no deck beam) simply lashed to the gunwales, as was the case with the masik, the curved deck beam which holds up the front of the cockpit.

Rather difficult to see in the photograph above, but the lashing to the deck beams is clearer in the ones below:










The keel line had a kink in it near the stern just discernible in the top photo. This was due to frame no 1 (numbered from the stern) being a little too high, this was confirmed by checking on the plan. Once this had been adjusted, the curve came out fine:

This naturally leads us on to the bow piece, shown temporarily fixed in the photo above. The previous post showed the hardboard templates which had been created from the offsets and the bow piece was glued up using cedar for the bulk of the piece, and oak for the nose area, so as not to snap on impact.

The three parts ready for glueing shown alongside the template, and then below ready for glueing, and then being glued. The nails form a framework against which the pieces, glued with epoxy can be wedged/pulled together. I coated the joints with clear freshly mixed epoxy to give good wood penetration before adding more thickened resin to ensure the joint had no gaps.

The finished piece came out like this:

And fitted against a small frame (lashed to the gunwale) to centre it and give it stability. The same process was repeated with the stern piece. The next post will show how they are all lashed and pegged into place.