Articles
Shadow Hull Building Photos
This photo sequence uses photos taken from two excellent builders blogs
http://www.flickr.com/photos/catamaran_tordo
and
http://pinoyboats.org/forum/viewtopic.php?f=2&t=1138
Although specifically for a Shadow/Strider Club, these pages will also be useful to those building a Strider, Gwahir, cold moulded Merlin and Skua
The bulkheads are marked and sawn out, note no lofting is required. It is best not to make the cutouts in the bulkheads (for bunk access etc) until after turning over. That way the bulkhead stays stiff and its easy to attach the legs
If you are building on a flat concrete floor, when you can use "Liquid Nails" or similar to hold the bulkhead braces in position, you will need to make a temporary building frame as shown. This keeps everything stable and so its easy to build a fair hull
Initial set up of the bulkheads, note temporary legs and, just visible, waterline string passing through each WL/CL intersect. Hull stringers are then added, epoxied in place and faired
The stem is very strong, after all, if you hit anything this is where damage will usually occur. The small knee helps hold the inner stem in position. The first bulkhead is always watertight
Once the stringers are faired planking is started. Two layers of 3mm (1/8in) ply laid in strips about 150mm (6in) wide at 45deg, first layer one way, as shown. The second layer is laid at 90deg to the first one.
The stem and keel stringer will need careful shaping to ensure the planking fits properly
Fitting the second planking layer. Note, because the boat has a knuckle the topsides are sheet ply. This makes it a much quicker build with less time spent finishing.
The double diagonal section is now finished, so the knuckle line is carefully cut to form a fair line.
Then the topside planking can be fitted
And the outer stem glued in place and planed to shape.
The hull is now sheathed with a light glass cloth and epoxy, at least as far as the knuckle but preferably the whole boat. Avoid overlaps where possible as they are hard to fair out
Use a "squeegee" to scrape epoxy through the glass until it turns clear
Fill and fair the hull and then you can fit the LAR keels. These are fitted on the outside so you can fit them at a later date. That keeps the hull nearer the ground so its easier to access when the right way up
Turning the hull over can be done singlehanded using rope purchases, but it is much easier and quicker to do it with a couple of friends. At this stage it will still be very light and also relatively delicate
Ready to deck!
And there is a great strip plank Shadow builders blog HERE http://saideira.net/