zondag 31 januari 2010

diy endless line furler (25 - 30 dollar)

For some time I have been toying with the idea to make a endless-line furler from standard automotive parts. Below is my fist try. It's made of an aluminium pulley (10 euro = 14 dollar), a standard skf double row ball bearing - type 3200 if I remember correctly - (10 euro), some stainless steel bolts and eyes and some plastic parts made of cutting board.

Since I have a backup forestay I can take some risks: even if the furler will fail nothing serious will happen.

The drum is a standard aluminium v-belt pulley (type Z). This pulley is 8 cm diameter. I would rather have a bit bigger pulley, but couldn't because my lathe is not big enough to handle bigger diameters.
I drilled 8 holes through the pulley (hope the photo shows the idea) to make sure the furling line won't slip. Big succes - the line locks in the pulley beyond my expectations.

Below the furler before assembly. From right to left: tang to mount the jib, cap made of cutting board to seal bearing, M10 bolt, bearing, the pulley with a recess for the bearing (made that with the lathe, of course), 3 rings to form a spacer, line-retaining drum made of cutting board (also on the lathe), piece of cutting board with an eye to feed the line, ring, nut with a hole and shakle.
I put the bearing in a liberal amount of grease, and sealed the bearing-recess with a plastic cap. I think this should be watertight enough.
The eye for feeding the furling line is held in place with a small recess in the furling drum (below).
Below a part I'm not too happy with yet: I used a 10 mm bolt to mount the shackle of the furler. Because it's threaded it's effecively less than 10 mm diameter, and with a 6,5 mm hole drilled through there is not much steel to hang on to. To fix this I drilled through the bolt and the nut, hoping this will be somewhat stronger. Added benefit: the nut is locked in place. I will probably replace this bolt by a unthreaded 10 mm rod.
Other part I'm not too happy with is the tang on the topside of the furler. there was not enough space above the bearing to just 'bolt through', soI fixed the tang with two short M6 bolts. Because the shape of the tang (wide, v-shaped), the forces on it will be quite high. I will probably think of another solution, but not before I have done some tests to see if the furler works.
Movie to show the furler: as you can see it can turn and swiffle in all directions, and it's not much work to put the line on the drum.(PS the movie is often down, I'm sorry)


video

1 opmerking:

Andrew zei

Great ingenuity! Looks like it works great. Also liked seeing your family enjoying the boat. Thanks for continuing to make updates.