Working drawings

These images are quite naff because they involved putting my working drawings [the ones I use down there on the clipboard to build the boat] on a box and me snapping them using the heavily distorting iPad camera.

What is skewed in these images I can assure is not skewed in reality but the shots do give you a rough idea of what I’m building.

The whole key, the one over which there’s been so much grief, is to do with the struts, the beams, known as the akas.  I can construct curved and complicated arches which are fine until storage on the canal comes in, with the hulls contracted.  Therefore, again looking at the contracted profile below, the beams need to sit flush on the lower deck of the main hull.

The hatch is in the raised section on the left. I had to look at how these are stored because it affects where the windows go in.

Now, the two shorter [cantilevered] struts are to hold the ship’s boat over the port side, ready to lower – [dinghy 10’10” x 4’8″] – but they also double as the beams holding the hulls together when contracted, as below.

Once the 18’10” beams are part-untied and the end-to-end rope on each beam pulls the hulls together, the long beams are removed one by one and the 6’10” dinghy struts are tied down in their place, the long struts then store above those lengthwise as previously indicated.

It took a long time to get these contracted to just two long and two short beams – you can still see in the diagram below the swing mechanism I had in the previous incarnation.

It took so long to get the volumes right and even now weight will have to be added or removed when the hulls come together.  That’s not difficult as I have 100 water carriers of 10 litres each.

I’ve left the side elevation till last because it’s not a daily working sheet, it’s the overall idea:

I could, if I wanted, change the rig to four full spritsails instead of two half spritsails at the stern but this seems the most workable arrangement.  It doesn’t need to be decided until it’s time to add blocks to the masts – there are four masts, that can’t alter.The first and fourth are 4″ solid, the middle two are 5″ solid, all on tabernacles [or swing mechanisms on deck].

Longest mast is 18’10”, by no means unmanageable for two.  Sails are tan canvas.  A new range has just come in so I’m glad I held off.  Better tensile strength now.

All beams are tied down to the deck, all running rigging and anything to be dismantled on the boat is tied, not screwed or bolted.  Those are nets [top pic] of 2’6″ connecting the various sections.

I’ve two rudders due to be built, with narrower blades but I could go one central rudder [main transom] and that would need to be curved and swing down and kick up – there is a mechanism to do that, quite simple but needs to be scalloped accurately into the rudder box.

There’ll be lee boards on the insides of hull and pontoon.  On a port tack, the main hull lee side is used, on a starboard tack, the pontoon’s in-side is used – always the lee side of the windward hull so that there’s less heeling moment, less fulcrum effect [tippy-over].  Leeboards are asymmetric. it is necessary to maintain the boat at 5-7 degrees to the horizontal crossways, doesn’t matter lengthways. Leeboard bolts are movable to four positions along gunwhales for fine trimming.

2 comments for “Working drawings

  1. August 27, 2018 at 17:24

    Looks a difficult labour of love.

    • August 27, 2018 at 17:36

      You should have seen the complicated version.

Comments are closed.