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Everything posted by jay

  1. Windy.com and their app have an ocean current model - how accurate is this for for NZ - in particular for timing of passages around capes? The current model appears to include macro tidal effects since it shows currents changing in sync with tidal oscillations, for example around North Cape or thru Cook Strait. However the model also shows currents passing thru land, so on a micro scale obviously not accurate. But for forecasting effect on currents of tidal changes around capes, seems like it would be useful if reasonably accurate at a macro level. https://www.windy.com/-Show---add-more-
  2. You might be able to line up one or more of the old holes with the new hole pattern, reducing the number of new holes needed. If you drill the new holes oversize 1st, then you can epoxy fill the old and new holes at the same time as described above, wait until cured, then re-drill the new holes to correct size taking care to only drill the epoxy fill. This way the new holes are epoxy sealed to stop water getting into the ply. Fairing might not be necessary if the holes are all covered by the new winch.
  3. jay

    Cold Front Today

    Here's a screenshot of the Predict Wind observation graph for the RNZYS station. Shows gust of just over 50 knots just before noon. I don't sail the area often, but gusts of this strength are not that unusual for the location?? Surprised there isn't a high wind warning system on the bridge to prevent this from occurring??
  4. jay

    Lithium v AGM

    I've used a 100ah lifopo4 on a 9m racer cruiser for about 5 years now for two reasons - significant weight savings and high charge efficiency. For me, these outweigh the increased cost. While I admittedly don't have expertise on this, I'm not aware of evidence to support the fire risk concern - there is plenty of guidance out there about how safe lifepo4 technology is, and by now I think we would be hearing more lifepo4 boat fire stories if it was a risk. Will probably get flak from some for saying this....
  5. MPS supplies carpet pads for the travel lift to protect the wrap so damage is not an issue for my light displacement boat. I think heavier boats should be ok as well, but suggest speaking with MPS on their experience here. The aggressive Bay of Islands barnacles are one of the reasons I went with Silikon. They are seasonal from approx Feb - April when water is warmest. Generally I swim to clean the bottom often enough that I don't get these barnacles with the Silikon, however when I cleaned the boat after lockdown, I did have some barnacles adhering to the silikon. They easily pop off wi
  6. Silikon wrap for a 9 meter yacht was approx $5k installed excluding prep 2 years ago. It is priced by the sq meter. Best to speak with MPS about recommended prep. Generally clean off all the old crap and put a nice sealing primer coat on for good adhesion, taking care to get good adhesion on this coating. Leave a few days before the silikon is applied. They did the application in one day.
  7. I've had Silikon from MPS for two years now and am happy with product keeping in mind there is no perfect solution. I do dive before races to give the boat a wipe-down which is relatively easy using a small 12v hookah. After lockdown and not cleaning for two months it had a fair amount of growth, which wiped off with bare hands. I did have some damage to the bow from a fergie buoy, my fault and since replaced with standard ball mooring, which was relatively easy to repair. Yes - it was expensive, but time it saves me in being easy to clean is worth it for me. Happy to answer questions if anyon
  8. I understand why a professional installer would use Hella from a reputation standpoint, but for the average boatie trying to keep costs reasonable, in my own experience LED technology is both cheap and reliable, and everything else is just marketing hype. If I ever did have a problem my spare emergency nav lights are easy to clip on. I was required by an inspector to move my gunwale mounted lights to the pulpit rail years ago even though other prominent boats in the area continue to have gunwale mounted lights and the forward angle of the new lights was checked and debated as to whether
  9. I also had tabs welded on similar to the above picture, but rounded at the front so no corner for kite to catch on. Keep in mind that the tabs should be angled out from the natural line of the pulpit so that when the lights are mounted they are parallel with each other as opposed to toe'd in, or the lights will need to be shimmed. The welder can also add holes where the pulpit attaches to the deck and tubing to run wiring.
  10. I had my bottom wrapped with Silikon this winter by NZMPS. Not cheap, but like trying new technologies. It's a foul release system, as opposed to antifouling. I don't go fast enough to self-clean, but it is easy to swim and wipe down before races. Takes about 25 minutes for 9m yacht using low pressure regulator and pump, and bare hands to wipe. Hoping I'll get several years out of it. I was previously using Ultra but the barnacles in BOI have been real aggressive over the summer season and seem to stick to about anything. Also biocides were spent after six months, so still had to clean regular
  11. If appearance is the main consideration, carbon fiber vinyl wrap works well too - get it on trade-me.
  12. This is what I use: https://www.burnsco.co.nz/shop/rv/hardware/latches-catches-hooks/flush-pull-latch Made specifically for the task. Mounts on washboard and locks hatch into place, can be opened from inside & out. Comes in plastic if weight is important or stainless if not. Never had issues with it and Cat 3 inspector was happy.
  13. Here's a picture of the hatch clasp I use. A number of the marine shops sell these. If you search google for "flush pull latch nz" you should find sources.
  14. To secure the washboards I have a small hole in top washboard with a cord passed through and knotted outside. Line then just stretches over a little hook inside that can be reached from either inside or outside when the top hatch is open. To secure the top sliding hatch, there is an inexpensive special purpose clasp fitting that can be operated from inside or outside that is sold by marine stores, in either plastic if you are weight obsessive, or metal. My cat 3 inspector a few years ago had never seen this fitting and thought it was pretty neat.
  15. These two websites have free ocean current models: https://www.windytv.com/?currents,2016-10-15-21,-35.299,174.375,8 https://windria.net/auckland-nz (click on the "currents" tab) Not sure how reliable they are?? particularly as one gets closer to east coast, but interesting to study. General NZ current diagram - http://calib.qub.ac.uk/marine/currents/NewZealand.html I have observed southerly current approaching 1/2 kt between brett and poor knights. I suspect Jon is right about east auckalnd current not being as strong this time of year.
  16. jay

    Navman gps

    For repairs you can try http://www.efrontier.co.nz - 09 835 2128. They repaired my navman a couple years ago and website still says they service navmans.
  17. Harken's calculator tells how to adjust for a square top. I believe this gives load under sail, as opposed to shock load? For example when doing an uncontrolled gybe, where loads would be much greater. Not sure how one would calculate the potential shock load, which would be more important for sizing gear? Also, can you use a winch for the main when it is under greater load?
  18. Advert says windward/leewards, but pictured boat is on a reach....
  19. Had one of these swim alongside my kayak once. Just looked down and there he was, about the same length as my kayak which is just over 5 meters. Could have touched him with my paddle....gave up kayak fishing after that.
  20. jay


    Per AA solar's website, their lifepo4 battery can be discharged by 50% 3000 times with almost no loss of capacity. This is consistent with other data available on current lifepo4 battery technology and plenty good for me. Too Tall - what you say about charging is generally not viewed to be true for lifepo4 charging. They are much more efficient to charge all the way up the charge curve than LA with no need for long absorption or float cycles. As a result, I don't need to charge from shore or solar, as it charges so quickly from my alternator.
  21. jay


    Thanks Wheels and Too Tall - the warranty was not a factor for me, other than as supporting evidence that provided I don't abuse the battery I should get a long life. I only raised it as I was concerned about the three-year life comment.
  22. jay


    I confirmed that my marine policy would still give me boat yard/haul out coverage even if I signed a liability waiver. The reasoning is that one can't contract out negligence, so the liability waiver only provides the yard with limited protection, and the insurance company would still be able to seek recovery.
  23. jay


    I think the cheaper inverters produce current spikes that confuse chargers. I ruined a couple lithium power tool batteries recharging them using a cheap inverter before I figured this out. Lifepo4 is very safe and not a fire risk.
  24. jay


    I went with an AA solar 100AH lifepo4 battery (13.2v system), Balmar 80AH alternator and MC614 regulator, and Victron dual battery monitor. This is for an elliott 9, so weight / performance were important to me. Hopefully long term economics will also materialize. Fast charge time when cruising is very nice. I have a switch so I only juice the alternator when I need to charge, and regulator is programmed to stop charging at 14.3v. Monitor tells me exact % charge remaining and current AH in/out, so real easy to keep tabs on charge state. I only bulk charge - no absorption or float. I kept my o
  25. jay


    Looks like carbon foam is even heavier than a comparable LA? I went with a 100AH Lithium house battery about a year ago and have been very pleased. Upgraded the alternator and regulator at the same time which needed replacing anyway, plus a good battery monitor. Big weight savings, plus so much quicker and more efficient to charge. Not the cheapest but hopefully better long term.
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