sailak

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About sailak

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  • Birthday 01/01/1980

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  1. sailak

    2 x 25A => 50A circuit?

    Look up the breaker "trip curve." If it is anything like the UL489 breakers you see in industrial environments (many Bluesea breakers under this standard) then 36 amps can be drawn for 120 seconds on a 25 amp breaker. In other words, you need two shits, at the same time, that are both 18 amp shits, that both take 2 minutes to flush to trip the breaker. The wiring will be fine since each is pulling an 18 amp shit.
  2. First time ever test nationwide... Did they think this one out? I am imagining bumper to bumper traffic when everyones cellphone goes apeshit and everyone goes to look at the same time. https://www.reuters.com/article/us-usa-trump-alerts/trump-administration-to-send-u-s-cellphones-a-test-alert-on-thursday-idUSKCN1LV0N6
  3. sailak

    2 x 25A => 50A circuit?

    I'll take that as sloppy wording and not technically correct, my apologies. The 80%/125% rules tend to apply to the wire, and since these are coordinated systems then require sizing the OCPD accordingly. These cases don't necessarily apply here but: NFPA 70 210.3 and 210.19 Could imply 125% (this also ends up in other sections of the code, 690 for example) NFPA 79 mentions 125% for the circuit conductors many times. This standard isn't very broad and is a little ambiguous, but it is in there. You could infer 80% from manufacturers derating factors: (diversity factors, more than 4 devices then you are less than 80% for an Eaton brand UL 489 breaker anyway) and at least the common Bluesea breakers are manufactured under the UL 489 standard. There is also temperature derating that could apply. UL Labeling standard: "Unless otherwise marked for continuous use at 100 percent of its current rating, a circuit breaker is intended for use at no more than 80 percent of its rated current where in normal operation the load will continue for three hours or more." (hope the head isn't on for more than 3 hours!) For the fun of it I tried the Bluesea circuit wizard, and for an 18 amp load at 20 feet, with 800CCA it recommends 10AWG and a 32 Amp breaker. Again, a lot of this is based on continuous loads and isn't the standard in the case of a boat head.. Honest question here: when would you select a breaker this close to the load current? I could see special cases where you are trying to protect the device but in my experience this ends up resulting in nuisance trips and eventually wearing out the breaker. The breaker in this case is generally there to protect the wire against overload and against short circuits. on a boat anyway 12AWG is good for around 30 amps according to ABYC, so a 25 or 30 amp breaker seems like the best fit. In this specific case would a 30 amp breaker not provide better service than a 20? I suppose if the 20's are working fine then go with them, and sure put both heads on 1 breaker. Its a rather pedantic topic but I'd be interested in a long term follow up. Edit: thinking about the breakers got me distracted. The "right" answer is to follow the instructions from the manufacture of the head, no? Here is an Example from Raritan, 18 Amps
  4. sailak

    2 x 25A => 50A circuit?

    By many standards 18 amps on a 20 amp breaker is already too much anyway, but for short time periods it won't cause a problem depending on the breaker. A load like that probably should be on a 25 or 30 (18A x 125%) depending on the wire used. Do the current ones ever trip?
  5. sailak

    Show your boat not sailing

    That reminds me of a scolding from my dad when I was about 17. "You know it is going to cost you a lot more if you keep driving like that." says dad. My response: "I know" Didn't know it could take that long for a boom... Money, sure, lots, but 4 months?
  6. sailak

    Bilge hoses

    Ok.. But I think it depends on the size. If you are talking 1/2 or 3/4" I'd recommend the clear reinforced vinyl just for that reason, it is clear and inspectable. It is nice to see low spots or crud building up inside the hose and relatively cheap. I do use exhaust hose for the scuppers (1.24-2"). It is generally the highest quality toughest hose you can buy. Ever run a blade accidentally across the marine head vinyl stuff? cuts better than butter... The exhaust stuff will hardly show a mark. The clear vinyl is actually pretty tough too. The cheap plastic bilge hoses are suitable for air ventilation maybe..
  7. Couldn't it just be sandblasted and sprayed with rhino liner?
  8. Used to live at Keehi. My slip would have been gone during the last tsunami episode there in 2011. Many set to sea during that event to save their boats. Can't imagine a hurricane as predicted here. Not many options. (looks like may not be all that bad for Oahu). Maybe things have changed over the last 10 years but most docks in most harbors seemed to be in a special state of disrepair. It was not uncommon for a slip finger to just roll over and give at least one of the boats tied up to it a barnacle buff job even in dead calm weather. Is storm surge as big an issue on the islands as it is on the east coast?
  9. sailak

    Sealing dyneema rope in a thru-hull

    I have one on my foredeck that I installed threaded side up and used heat shrink, although that was with threaded rod. 5200 may work but I would try G/Flex epoxy first. It is almost as flexible as 5200, I think sticks better, will certainly seal better and will be a lot less messy. That said I suppose I could envision it wicking into the fibres more and maybe making a hardspot? Removal would involve a little heat but nothing too extreme.
  10. Replacing some of my portslights.. some this fall and some next spring. I used Interlux epoxy Primekote on the areas I glassed in. Would it be okay to leave it over winter? I only used primekote because I had a little left and also used epoxy fairing compound. Next spring I plan on doing the rest of the cabin sides with regular pre-kote primer and single part polyurathane so I would end up likely going over the epoxy primer with the pre-kote anyway.
  11. sailak

    Keel fell off, accident report

    Yes.. This is the same thing that mostly keeps wheels on a car. slip critical or friction critical joints are very common, predictable, reliable, and do not use to large degree the tensile strength of the fastener. When a fastener tensile strength is part of the mechanical joint special care must be used. Generally somewhere around 3/4's of the tensile strength is used up when torquing the fastener so there is much less margin for error. What is a torque wrench for? torquing a bolt.. nope, not at all... stretching it.. yes. Torque is a proxy, and a pretty crappy one at best. Then hanging a mass of lead and imposing dynamic loads on what little of the elastic range remains.
  12. sailak

    Heat treating stainless

    It will be work hardened by the process described.... but heat, no. I would try again with maybe bronze, monel, titanium something like that or just a larger cross section for the SS wrench. Interesting problem.
  13. sailak

    State of the art boat wiring, 1959.

    I use the Brady heat shrink labels a lot... love em. Yeah, they are pretty nice on a boat panel but of course simple sharpie will do most of the time. I never liked just regular numbers even for industrial jobs unless the system is well devised. The best done industrial wiring labeling I have seen guides you to the precise grid coordinates of a particular wire and terminal in a thousand+ page wiring schematic. That was done by Hyundai. Most of the time it is just a vague idea. For a boat a simple description is best for sure. Don't forget to label the DC negatives!!!! At least half the time that is where the problem is (maybe more so since it is so often thought of last?). Thanks so much for the pictures too. Really great to share stuff like this.
  14. sailak

    State of the art boat wiring, 1959.

    I like the old bus bar.. Looks like a 10 AWG solid piece of wire. What kind of connectors are used on it? Rare to see wiring that old still working. Most of the boats I have worked on are on owner cobbled version 2 or 3. I worked on a early 1970's Hatteras that had OE wiring in fair shape, but the gremlins seem to have nested and no one could figure it out. Craftsmanship was pretty good. Those switches are pretty stout. They don't make em like that anymore, but I think our contact plates are better material and certainly have better plastics. I'd pass on those fuse holders...