This project has the advantage that it is great fun to use when finished but it requires very good lashings and secure guying to remain stable during enthusiastic use.
- 6 x spars 3.6 metre (12 ft) long
- 6 x spars 3.0 metre (10 ft) long
- 1 x scaffold board 2.5 metre (8 ft) long
- 22 lashings
- 4 x ropes 8.0 metre long for guys
- Large pegs or pickets
2 x A frames are constructed using 2 x 3.6 metre and 1 x 3.0 metre spar.
The top of the sheer lashing needs to be approximately 1 metre below the top of the long spars. The horizontal spar needs to be approximately 450 mm above the butts (a).
Join the A frames together using the remaining 3.6 metre spars (b). The lower spars need to be as low as possible, otherwise they may prove to be a hazard to the swing boat.
Lay the structure on its side. Join the tops of the A frames by lashing 3 metre spars to them and then, at right angles, lash the last 3 metre spar as a fulcrum across the centre ( c).
Hint: Lean the A frames in slightly at the top to make the structure more stable.
Tie two of the lashings to each end of the spar between the crutches of the A frames using a round turn and two half hitches. These will support the swing boat.
Tie a rope to each end of the fulcrum spar.
Stand the structure on its feet.
Suspend the plank from the four hanging ropes. It may be necessary to notch the plank, or nail blocks onto it to prevent the ropes slipping.
Peg out main guys. Drive in pegs near the feet of the A frame and lash to the structure for stability.
Useful Hint: Whilst the structure is laid on its side it is a good idea to tie on four main guys.
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