Jump to content

FORTUNATA

Member
 View Profile  See their activity

  • Posts

    1,985

  • Joined

  • Last visited

 Content Type 

Blog Entries posted by FORTUNATA

  1. FORTUNATA

    Curse Of The Pram Covers

    By FORTUNATA,

    Have you ever noticed how people who own old boats suffer due to boat covers? Not that boat covers don't serve a purpose or that they're not well crafted or even attractive. I'm sure some companies make really great pram covers and I know many people who love the idea of having one (you can shelter from the rain while driving your boat, after all).
     
    Even so, I confess to being totally puzzled why boat builders used to make boats with widely exposed areas of the stern at the mercy of torrential rain and snow. Lift up the deck-boards and you'll find a bilge swimming with water. If the boat is old, paint will have flaked off the bilge and you may find trapped air and pitting. Those who can't afford a boat cover or simply haven't had time to get one fitted, will spend hours draping building- site sheets over the stern. They will many times risk a fall into the canal as they struggle to find something to knot a chord onto so the sheet will stay on. I've even seen people make temporary planks under the sheet to try and persuade the water not to sink in, but to roll off the sheet. 90 per cent of these efforts wind up in failure. You can see many a boat with a collapsed sheet where the water has formed an ever bigger puddle, finally ripping the sheet and unleashing gallons of water into the bilge.
     
    Who builds a house with no roof on the kitchen, expecting the occupants to wrestle with sheets so they can sometimes go and make a cup of coffee without getting soaked? Madness isn't it?
     
    Having suffered all of this for too long, I've decided to try and convert my knackered cruiser into a sort of semi traditional with a self-draining deck. The plan is to repair my deck support girders where they've rusted, try and seal any gaps between the girders and the sides of the hull and later attempt to fit decking that's cut precisely so any rain will go between the gaps. Drill holes or channels will need to be placed so the excess water can drain overboard. As the boat is very old, the girders were only put in as supports for the decking and there seems to be no drain system.
     
    I'm not a boat-builder so I'm aware my chances of success are open to debate. For now I'll try and break it down into stages. It may be fair to say that even the designed self-draining decks will struggle if the rain becomes torrential or if it snows so the water melts all in one go.
     
    At least it's an attempt to fight back and a refusal to be yet another victim of the soaked bilge syndrome.
     
     
     
     
  2. FORTUNATA
    Ever wondered what the difference is between a valve or electron tube and a semiconductor? Which is better? What about sound?
     
    The simple difference is the electron tube needs much more voltage to work than does a transistor. Another huge difference is the electron tube diode conducts through free electrons within the tube. That is, whereas in semiconductors the electrons orbit a nucleus of an atom (silicon atoms, for example), with tubes the electrons are free.
     
    Tubes are actually quite simple and are far more robust. First the filament is heated by about 5 volts or less till it gets very hot. That releases a cloud of electrons around the filament. Another electrode (plate or anode) is in the tube and connects to positive (say a battery + terminal. If you connect the battery negative to the filament, you then have a diode. Current flows from the cathode (filament), through the tube to the anode and to the battery. Current will flow only one way.
     
    It's exactly the same as an alternator diode except conduction is free electrons in a tube and the voltage is far higher.
     
    Enough theory. It's hard to say why tubes were dumped to the degree they are today. Some are actually quite small. The audio quality is really good. One of my sets gives 280 volts of audio output and gives a rich, deep sound.
     
    They more or less became obsolete in about 1965 or around but have always had some role to play in music recording and Rock bands like The Stones swear by audio tubes.
     
     
     
     
  3. FORTUNATA
    If this publishes O.K., a few words of introduction: I thought it would be a good idea to do a blog on vintage radio and vintage marine engineering as well. However, with respect to boat engineering it will be less "vintage" and more "eighties" when boaters were keeping it simple with prop-generators, TWC regulators, split-charge battery banks and, yes, large and noisy engines.
     
    As to the radio side, I repair radio equipment from the Thirties, Forties, Fifties and Sixties. I'm not an expert but I've managed to fix a few sets and have a tendency to listen to my Forties era radios on the boat.
     
    Seeing as many people afloat tend to have plenty of knowledge of electronics, I'd be happy to help get you started with radio.
     
     
     
     
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.