Sunday, October 22, 2017

Best 100--Chapter 11

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Saltwater and electricity don't get along, or rather they get along too well, causing all manner of corrosion and non-conduction problems for the sailor. Keeping the electricity flowing between the lines is the problem.

One of my first published articles, in 2010, involved making up over 200 crimp connections and keeping them in a salt spray chamber for a year. I've also had boats in the water for 30 years and observed the result of factory, PO, and personal errors. What I have learned:

 Hopkins 47965 2-Pole Flat Extension66. Trailer Connectors and Grease. I've tried many brands of waterproof deck connectors. All of them seem to fail in 2-5 years, they are expensive, and pricey to replace. Recently the power conector on my Raymarine Autohelm 2000 failed, and a replacement set was $168.00!  Unbelievable. Flat trailer connectors (available in 2, 4, and 5 pin) are cheap, reliable if packed in grease, and a new one can be crimped on in minutes if you leave a loop of wire. They have been the standard for 75 years, so I'm not expecting change. It also proves they work. My choice for rotating masts, tiller pilots, and solar panels.

67. THHN Machine Wire Copper Wire vs. Tinned Wire. Heresy you say. In fact, both are approved by the US Coast Guard, and both survived my 1-year spray test for Practical Sailor Magazine with zero failures. There are differences in corrosion. Do no use finely stranded (like lamp cord) copper wire without tin plating; i will not hold up. Additionally, when it comes time to repair copper wire, the corrosion may well have traveled far up the wire. However, in dry areas of the boat, does the extra protection mean anything? If the breaker panel, for example, goes underwater your going to rip it all out anyway. Many quality boats use lots of non-tinned wire without complaint.

Do use tinned wire to all exterior lighting, around the engine, and in the bilge. You won't regret it.

Pitch the cheap crimpers in the trash. And I'm cheap!

An inexpensive pair like this works for me. Just make sure they are adjustable (star wheel near "Titan" label). I have a fancier one at home, but I'm not convinced it is better for occasional use.


68. Ratchet Crimpers. Remember how I said I did over 200 crimps for a PS test program with no failures? The key is to throw away any non-ratchet crimper. That's right, pick it up and pitch it before you do any damage with it. They just are not repeatable enough. Instead, get a ratchet crimper, adjust it to the brand of fitting you will be using (no Harbor Freigth stuff, but the Home Depot stuff is fine), and make a couple test fittings. Clamp the eye in a vice and try to pull it off the wire. The wire should not pull out. In fact, either the wire should break or the fitting should tear.




69.   Grease. Forget the sprays. They don't hold up in marine conditions. Forget conductive grease. Many can cause dissimilar metal corrosion and "conductive" in the sense you understand is pure myth. They are insulators except at extreme voltages, where they can bleed off minor charges (never use conductive grease on antenna connections or spark plug wires). Vaseline can work, but it melts easily and has inferior anti-corrosion properties. Dielectric grease is good for sensative electronics and antenna connectors, but in general, good old waterproof grease or Lanicote is the correct choice. Use this on all studs, terminal strips, batteries, and all mechanical contentions (not required inside the crimp).

My favorite for electrical applications is No-Ox-Id Special A. It has been top performer in all of the extreme exposure testing.

For mechanical (based on corrosion and wear testing), including winches, Green Grease (Omni Lubricants) from Advance Auto is the top pick. For antisieze on bolts, Tef Gel is very good. Also Locktite Marine Grade LB 8023 (not just any anti-seize--some of the non-marine formulas contain dissimilar metals and can make it worse).

70. Separate Heat Shrink. Not technically about equipment, but sort of. Instead of buying pre-insulated crimps with adhesive lined sleeves, buy the heat shrink separately. Not only is it much cheaper, the odds of the insulation sleeve being damaged by the extreme pressure of crimping are very high, perhaps over 50%.  So instead of buying the over prices all-in-one crimps, buy economical insulated crimps, use them as-is for most cabin applications, and then cover them with separate lined tubing only when used on deck or in the bilge. This also reduces the required inventory of crimps.

3 comments:

  1. Trailer connectors! Brilliant. I have the same opinion of through-deck or weather-proof connectors. That's why I did this: https://middlebaysailing.wordpress.com/2012/07/17/mast-wiring-connecting-with-the-boat-wiring-harness/
    Never thought to use them in lieu of 12-volt plugs, but I will now.

    Non-tinned wire below decks - now I don't feel guilty about using it!

    Ratchet crimpers - well, I use vice grips and never had a failure - I crimp each fitting twice, the second time with a tighter setting on the locking pliers. I'm cheap too, and could never justify buying expensive specialty crimpers when locking pliers seemed to work well.

    Lanicote may be the best, but so far vasaline has worked very well. Next time, I'll pick up some Lanicote, though.

    Crimping does seem to damage a lot of fittings, and I've always bought the less expensive insulated kind also, but it's nice to know that I'm not the only one who's had that experience.

    Good stuff- thx!

    ReplyDelete
  2. Trailer connectors! Brilliant. I have the same opinion of through-deck or weather-proof connectors. That's why I did this: https://middlebaysailing.wordpress.com/2012/07/17/mast-wiring-connecting-with-the-boat-wiring-harness/
    Never thought to use them in lieu of 12-volt plugs, but I will now.

    Non-tinned wire below decks - now I don't feel guilty about using it!

    Ratchet crimpers - well, I use vice grips and never had a failure - I crimp each fitting twice, the second time with a tighter setting on the locking pliers. I'm cheap too, and could never justify buying expensive specialty crimpers when locking pliers seemed to work well.

    Lanicote may be the best, but so far vasaline has worked very well. Next time, I'll pick up some Lanicote, though.

    Crimping does seem to damage a lot of fittings, and I've always bought the less expensive insulated kind also, but it's nice to know that I'm not the only one who's had that experience.

    Good stuff- thx!

    ReplyDelete
  3. You can get moderately priced ($25) crimpers at Advance Autoparts or Sears. The Ancor crimpers are nice, but not required. What is required is that you adjust the crimper to fit the fittings you use (there is a small dial on the side). Also, ratchet crimpers will do less damage to the insulation than vice grips.

    There is nothing wrong with less expensive but still name brand crimp fittings. I've tested thousands, on boats, in the lab, and in industry. The only way they fail is if they are under crimped. Just avoid Harbor Freight!

    It doesn't need to be Linicote. Actually, the best all-around grease for boats (I've done a lot of corrosion and wash-off testing) is Green Grease by Omni Lubricants, also available at Advance Autoparts. Better than expensive winch lubes.

    ReplyDelete