dinsdag 29 juni 2010

Pulpit, furler, tiller-tamer

Yes, this is yet another go at the diy furler: mk3. The all plastic cage on my furler mk2 didn't work as well as my furler mk1, because the furling line had a tendency to slip on the drum. Feeding the line in and out via one big eye works much better (actually it works perfect). For the rest the fuler is the same as my Mk2. From this weekend on I'll be sailing with my family for hopefully about three weeks, after that I can probably tell if this furler works in all conditions or not.
From a distance the boat still looks quite good, in my humble opinion. Here we are anchored in knee-deep water.
Below my 'tiller tamer'. Simply release the shockcord from the camcleat to release the tamer. With the tamer tensioned, there is enough friction to keep the tiller in one position.
I originally planned to put bownets on my boat but after having a good look decided it's probably not worth the effort, as the nets will be very small.
One thing I however DO recommend to install is a pulpit. Originally I thought a pulpit would just be for show, but after having been forced to go to the foredeck a few times with a bit of wind and waves to sort out the jib I know better. It's very uncomfortable and (in my opinion even) dangerous working on the tiny foredeck without anything to hold on to.
I thought making the pulpit myself would be a nice opportunity to learn something about working with metal tubes and a good excuse to finally buy my own MIG welder. I bought a 200A inverter MIG welder. It's about the max I can run on domestic power (even had to put heavier fuses in the fusebox, as it would blow the normal fuses by just turning the welder on).
Step (1): make a mdf mold to make the big bend at the front of the pulpit (here I'm using two 18 mm pieces of MDF).
Step (2): probably not necessary: make recess in the two halves of the mold with a router, after that I glued/screwd the halves on top of eachother.
Step 3: bend by hand. This bend was around a mold with the radius the bend should have in the end. Not a good idea, as the tube has a lot of 'spring back'.
So..... I made a mold with a smaller radius, and did the final bending on that. On the first try I was not careful enough and extended the bend too much. Couldn't rectify that and had to start all over again with a new tube. With the below 'design' for bending it's however easy to carefully bend bit by bit - bend - check - bend - check etc. This worked well, but to bend like this (with a lever) it's necessary to first make a part of the bend by hand on a lager mold (as above) as it's only suitable to do the finishing bending.
Maybe it's because I'm not a metalworker, but the dwawings of the pulpit weren't very helpful to me. In the end it was easiest to just set the pulpit up with some scrap wood and some lines on the floor and measure & cut & grind till all the pieces more ore less fitted the drawings.
For the tube notching I found this tip helpful.
Because I had to do a lot of tube-cutting I had a good excuse to buy yet another tool: an Evolution Rage 3S mitre saw, which is supposed to be able to saw metal, wood and plastic with one blade. That sounded just perfect for me - one machine fits all. Big mistake. This machine itself is pretty lousy build but the worst part is the blades. They wear down very fast. I ruined one blade half way building the pulpit, and the other is already starting to get blunt. I know stainless steel is a pain to saw, but a few cuts in thin walled pipe shouldn't be too much to ask, now should it? In short: I should have known it sounded too good to be true and should have just bought some extra metal-blades for my table saw.
Welding the tube: put all settings of the welder as low as possible, and just spot weld round (starting with 4 welds: top, bottom, sides). This seems to be the only way to weld the thin walled tube without burning through.
Below end result, with welds roughly ground. Total cost material: 35 euro for 4 meter tubing (type 304, 20 mm diameter, 1,5 mm wall) and 10 euro for the ss plate to cut the baseplates from.

Ian Farrier recommends to first test-fit the pulpit before welding. That's not a bad idea. I first welded the frame of the pulpit, and after that test-fitted on the boat. It didn't fit perfect, and I had to make some adjustments before welding the aft base plates. The front base plates should be just in front of the front bulkhead, but in my case this didn't work out. I managed to drill two of the four holes of those baseplates IN the front bulkhead, aaaaargh. I'm not going to correct this: I will just fill those holes with epoxy and tap a thread into the epoxy.