Tuesday 21 April 2015

Legs part 2

I decided to make the legs demountable, this involved a bit of quick maths regarding the diameter and wall thickness of the tubes. The general idea was to make the legs in two parts that fitted together neatly to make each leg. It was important to remain within Paul's over engineered specifications and I ordered a smaller piece of tube with the same wall thickness to make a joining piece or internal sleeve.
I got the maths just right! The internal diameter of the big tube was exactly the same as the external diameter of the smaller tube, consequently they didn't slide together easily or even at all! Oops......
I needed an engineer, one of the best local men for the job has to be Steve Trippier, Pete very kindly offered to give me and the tubes a lift to Steve's and asked him to turn about 10.000th of an inch off the smaller one and cut the long tubes in two. As a bonus we also got to look around Steves shed.

Steve on left and Peter Manning on right.

Along with several vintage motorbikes, stood alone in splendour, there is Steve's steam engine that he has built from scratch. It is intended to fit it in a steam launch.
Strangely Lynne has no interest in sheds, it must be a man thing.......Steves shed is in the elite class of such things, a magnificent shed.
A few days later the tubes were returned and now fitted together with surgical precision


No matter how I try Lynñe still finds shoes infinitely more interesting than engineering!
However a few more days work and Dark Tarn will be able to dry out supported only by these two tubes and sitting on her keel. We intend to do this as a first test in the river Fal in Cornwall.


We have also been busy fitting the liferaft on deck, this seemingly simple job involved us removing several deck fittings that held the kedge ( secondary ) anchor, filling the holes and fitting six retaining blocks. In order to accommodate the deck camber it was also necessary to fashion some iroko wedges to raise two of the blocks and keep everything level, these were sealed with epoxy and varnished. They can just be seen in the picture. However the major problem with jobs like this is inside the boat as every hole has to be measured carefully to avoid stringers and other structural parts, this requires the headlinings to to be removed, a job that Lynne is becoming expert at! It is also very disruptive especially when you are also living aboard.
While the headlinings were down we took the opportunity to renew the polystyrene foam insulation and refitted the light fittings. also everything needed to be primed and painted also bedded on sealant..
Hence the fitting of this raft took nearly a week.
It's fitted with an HRU or Hydrostatic release unit ( it's the cylindrical object near the mast ) hopefully never to be used it will fire and release the raft should the boat sink and the HRU senses it is between 1-3 metres underwater. The raft is released manually by means of a 'Senhouse Slip'. Yet more names for Lynne to remember! I'm sure she thinks I make these things up............

The liferaft in position.

No comments:

Post a Comment