Trawler

April 3rd.  Trawlers have arrived, no problems.  Stuart sent the revised file and I have compared it to my final file, five errors but also some of the bridges are just too short in my original.

March 30th.  Email from Stuart, several problems: firstly late delivery of plywood, secondly, the file I sent did not translate well to Stuart’s laser cutter (again) and thirdly the file still had errors.  Stuart kindly corrected the errors and redrew the whole file then added a layer with the engraved 2mm bridges.  Neither of us understands why the file will cut at UWE but throws up errors on Stuarts machine. Stuart also had problems holding the plywood flat.  In the end I have 10 trawlers on the way.

March 18th.  Sent the file to Stuart at Cut & Burn to get 10 trawlers cut.

February 22nd.  Much better cutting session, both the trawler and the roro ferry came out quite well.  Still a few changes but I think I am nearly at the limits of design for the material – 3mm plywood.  The tenon tabs which are 15mm wide now have tapered sides to aid assembly, mortice tabs are increased to 25mm wide to improve strength.

Toy Trawler, 18cm x 10cm x 10cm, demountable, with moving parts

February 8th.  Arrgh!  Nothing went right with this session, other than lots of assistance from Lisa (technician).  But while not successful the session proved to be very useful, in highlighting the design error and  the cutting difficulties.  The errors are firstly, the mortice deck joints are too weak, they need to be bigger and therefore the tenon slots in the boat sides must be enlarged.  Secondly, the bridges – engravings which stop the cut pieces from falling out rather than being press-out – are too short and in some instances too long, they need to be around 2mm and correctly joined to the gaps created for them.  Thirdly, the stern door needs a re-design as does the winch.  Finally the whole drawing must be again checked in detail in Illustrator, looking for unwanted lines (usually found lying on top of wanted ones), unnecessary ‘anchor’ points, scale errors and so on.

Exploded view
Exploded view

The other issue which came to light was the difficulty of 3mm plywood, it is usually warped, has variable thickness and will not lie flat on the laser cutter bed.  My collaborator Stuart at Cut & Burn tells me he uses magnets to hold the ply down.

January 27th  Finally completed the changes  – including reducing the curve of the deck edge, by abut 1mm – to the trawler and have arranged a cutting session Wednesday next at Bower Ashton, using both plywood and, for the first time perspex.  I don’t foresee any further changes but…

January 11th   Made further cuts at Bower Ashton last Monday, not really successful.  The main issue was the press-out bridges, these are too strong and need to be reduced.  But the ease of assembly is not correct – too hard.  This is due to the curvature of the decks, which gives stability but at a price.  The ratio between material thickness and size of the design is highly critical.

January 4th  This is a design for a laser-cut plywood trawler toy, demountable, similar in design to the RoRo Ferry.

The basic design was completed at the end of 2016 and sent for prototype cutting today.