Thursday, 8 July 2010
I wont say it but, .....I could get rather excited soon. Things are taking shape and im more optimistic now than ive been for 12 weeks. Took more pix today, showing the stern being built up to include the fuel tank which is the full 10' 5'' width, divided in two for dual fuel storage, and incorporating the rudder post box. My initial calculations of 108 gallons of fuel appear to be almost spot on. Approx 460 lts. Not the kind of tank you want to fill up every week when you do the shopping, although I would get a few loyalty points.
The square box in the centre is called a weed hatch. It enables cleaning and changing of the prop without the need to crane out or dry dock. A handy thing to have on the canals where there can be ropes, plastic bags, weed etc that can and do get tangled up in the prop.
Also in the frame is a shot of the stern tube gland. Water stays on the outside of a boat, if it comes in, you have a problem. But, we need to have the prop shaft going through the hull, and it needs to turn, so what stops the water coming in through the tube?
Answer is a gland. At the inboard end of the tube, inbetween the tube and the shaft is a graphite grease impregnated rope seal thats held in place by a collar which can be tightened by two nuts. There must be some gap between the two otherwise it would wear rapidly or get so hot it would melt or even catch fire. Having said all that, a minimal amount of water must be allowed to weep through, and this is controled by the nut tightness. If it didnt weep through, you would know the gland is too tight.
The whole assembly is only 12'' under water so the pressure is minimal, but water always wants to level its self, so this seal is essential.
Other examples of this type of gland can be found in all domestic taps, where the handle shaft goes into the body of the valve. The shaft can turn, but water cannot come out of the valve body.
Martin is in a better mood at last. He talking, engaging in eye contact and even smiling now. Two weeks ago he would hide from me when I dropped in at the yard and the atmosphere was frightful.
Apparantly, for some reason, I intimidate him. Cant imagain why though, im always nice, pleasant and smiley, except when im being lied to. Grrrrrr.