Friday, 21 February 2014

Board Building Project - HD Creeper 48 - Stage 2 - Bottom Sandwich

Well I am a few steps ahead of this post so I thought I had catch up otherwise I will never find the time...

Well our recent heatwave has stretched the timeline a little, 40 degrees in the shed over the weekend and the high risk of blackouts meant bagging the bottom was too risky. Last night we had gale force winds and blackouts in adjacent suburbs so I thought I would do what Forest Gumps mate did on the shrimpin boat and try my luck with taunting the weather gods otherwise the board will never get finished. With the howling wind it was pretty hard to find bag leaks and my first run with the new vacuum system highlighted a few issues:
  •  I need a much bigger vacuum reservoir for the bigger bags which always seem to have a few leaks. I like FormulaNova's idea in the Seabreeze vacuum system thread of the pipes down the shed wall... 
  •  I won’t try sealing the vacuum tube in a mastic "zip" in the bag opening again! Get it sealed and it opens 15 minutes later. 
  • I need to cut the bloody corner off of my rocker stick so I can feed the bag on more easily. 
  • I need to tape the FULL length of the rocker stick to the Dcell. 
The power was on when I woke up and the digital alarm clock wasn't blinking so I was relieved. I went out to the shed to find only -4kPa on the gauge but the bag had good clamping force, looks like the base went on well. The stupid mastic wad worked itself free from around the suction tube so I think I will go back to the old through bag fitting. I will also try out some clip lock seal on the ends of the bag as I use really heavy 200um LDPE for durability. The mastic/tacky tape used was purchased in 2007 and may have lost some of its sealing and leak filling properties as the folded tape in the corner folds of the bag were creating slight leaks at the end of the tape and not staying sealed.

I tried placing the rail and outline templates on the deck to equalise the forces on the foam, looks like it worked pretty well combined with the low clamping force of -25kPa with 5kPa hysteresis kicking it up to 30. I still have the stringer 9mm proud on the deck so the templates butted up nicely to the side rather than overlapping and pushing on the stringer. If the templates were to overlap they might fight against the clamping pressure of the rocker stick holding the hull d/cell onto the underside of the stringer.

 I made some changes to the tail by adding some winglets behind the front foot, widening the tail under the back foot and then adding some bigger wingers behind the back foot for a pinnier tail.

Last night I finished hotwiring the plan, and marked out the rails for shaping. I ended up squaring off the nose to match the tail and I have always liked them anyway... 

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