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Everything posted by too_tall

  1. Is that number large enough to seriously hurt Garmin? They are a very large company.
  2. Checking to make sure there are no parasitic loads on the house bank is always a good move if your finding they are not lasting as long as they should. Sometimes a few owner installed devices may have bypassed the shunt for the battery monitor. If one of those has a constant draw ( either due to failure or simply thats how it operates but you cant easily measure it ) then you will get erroneous readings on your battery monitor. Another thing I have found to be a useful method of maintaining your batteries is to do a big charge early morning, get those batteries up to the absorption state (
  3. Interesting take with a knowledge of the big ships thanks Rigger. It certainly can explain quite few things. Leaves me asking one thing though - how did the naval ship not detect the merchant ship? I would have thought that there would be automated systems that would detect "threats" - which is exactly what the merchant ship was, albeit unintentionally. Our AIS and radar will alert us of collision or near collision course threats - and surely we don't get to enjoy the same level of tech as the US navy do?!? Surely??? Anyone with knowledge of systems on naval vessels?
  4. With regard to the relative thrust of same sized internal combustion vrs electric motors, the electric at say, 20hp will have a more consistant ability do deliver 20hp. A 20hp internal combustion motor requires correct propping ( as that 20hp only occurs at a narrow band of the rev range, wereas the electric will be over a wider range ) and to operate at 20hp its operating at full load - and probably will get heating issues if its really at its power output limit. The electric motor at 20hp is operating at its rated power output, and will do so until it runs out of joules to chew on. So whilst
  5. As with many things, this is very much the best truth regarding electric propulsion ( cars and boats )
  6. Is the overall concept of electric drive not really something that should be looked at on a new build as opposed to a retrofit? Imagine some form of azimuthing, fully retractable drive system, potentially a pair ( one in bow, one stern to give full control when docking ). Being retractable you get no drag when not requiring thrust. The entire design of the vessel would not have to be compromised by siting, and access, to an engine, fuel tank etc. No stern gland to leak. Sailing optimized rudder and keel etc. The benefits are large. The cost, well, I don't know. I still think that the only way
  7. I am not going to weigh in on the electric vrs diesel debate here - different people have different wishes and therefore different systems will suit. All I want to add is that in some situations, a well maintained, carefully managed diesel motor can very comfortably run past 20,000 hours, whereas in the exact same installation with poor maintenance, short run times, harder use etc, that same motor could be a very tired motor after 4000 hours. Remember that an average yacht motor does not do that many hours per year, and as a result, maintenance can be casual at best. We have a policy of annual
  8. We may do, we have the screen one, rechargeable. I will check on the plans for it. They do have a 160 character limit for messages, which is frustrating, and you really want to pair them to a cell phone or tablet to use them for messages as typing on the unit itself is a PITA.
  9. Hamilton chemicals will carry everything listed in this thread. Unfortunately couriering some of those chemicals is not so easy as they require certain safety measures to be met. The guys at hamchem are pretty good to deal with and the prices are astonishingly low compared to what you get from most other places. The guys at Hamchem will also advise on what safety gear and precautions you realistically need to take when handling the stuff. Remember that some of this stuff is fairly dangerous on its own, and having an accident with it and mixing, say, a bleach with an acid can be very much fatal
  10. too_tall

    DIY autopilot

    Fully agree, although they are comparatively low volume products which means everyone wants a larger clip of the ticket. Also, there are R&D, support, warranty, distribution, marketing, administration and many other costs you have to figure in too. I once spent quite a while discussing true cost vrs per item cost manufacturing cost with the owner of a company who design, build and sell globally, hifi products. His take was that for every dollar spent at a manufacturing level to produce a product, that their company, as a low volume manufacturer of higher end goods, would have spent
  11. too_tall

    DIY autopilot

    Awesomely simple and cost effective innovation. 3D printing opens so many opportunities for innovation at a DIY level. Edit. Or did I misread that as to be you used parts from a 3D printer, not made on a 3d printer?
  12. too_tall

    DIY autopilot

    Have you used a rudder position sensor to make this work for you? Or have you managed to get a position signal from the linear actuator? ( I guess with a LA you can have it do a full sweep of the range and it can then make a guess at rudder angle based on prior movements of the actuator? ). It all sounds like a fun project, although the software and tuning could be the part which would make me pull my hair out. I have quite a number of Arduinos running various things on the farms such as monitoring water systems, fencing, etc, We have moved more toward using a Raspberry Pi for most thing
  13. too_tall

    DIY autopilot

    Awesome work. Do you find that the tuning is the difficult part? Making it respond in an orderly fashion would be where I would have thought the problems could arise. damping the motion of the vessel so the actuator is not constantly operating.....
  14. One thing to point out - with a watermaker, stored water is still essential. Keep your tanks topped up as opposed to only carrying what you need till you next plan on running the engine. 100L of water might sound like a lot, till your method of topping it up fails. Specially if you are weeks away from getting fresh water or being able to implement repairs.
  15. Do you have access to an IR thermometer? Might be a good way to see if the temps are jumping around or not.
  16. Yes, I think that they may well have had other issues going on too - who knows what other damage was done? But a quick calculation of travel time, should the conditions be reasonable enough to be able to motor in a direction that is going to lead to a 1300Km trip. 700nm. Maybe a travel speed of 3.5kn? Or with no mast and stability, would that be unreasonably high? Of course, a lot less windage now... But thats 200 hours motoring. 8.3 days. at, lets guess around 2.5 - 3 lph? 500 - 700 liters fuel. On a 13m yacht which has already travelled from South Africa. Very, very unlikely to have suff
  17. too_tall


    The reality is that batteries contain a lot of energy, and when that becomes uncontrolled, it ends poorly.
  18. Go for the thickest wall section you can afford. The weight penalty is small. The strength benefit is significant.
  19. too_tall

    Solar setup

    Even better than freezing down simple water to create ice, make salted ice. For every 58g of salt added to a liter of water, your going to drop its freezing point around 1.8 degrees centigrade. Use your domestic freezer to freeze this down in a few old coke bottles or similar ( I put in 100g as its easy to mix ). Being that little bit colder, things stay more frozen for longer.
  20. I would not be wanting to potentially compromise the structure of your hull. The bulkhead is most likely considered vital ( although I am no engineer ). I would consult with an engineer or at least a well regarded boat builder before considering anything dramatic.
  21. It looks only half irresponsible. Moderately calm and obviously someone else on the vessel to rescue the monkey when his grip proves ineffectual. And its not night time... Surely the comment should be "whatever could possibly go wrong?" No doubt NZL1 is looking in taking notes on all the threads that will require the all knowledgeable one's comment.
  22. My reason for asking was because if you had tried using an electric heater and found it sufficient, then a 2.4Kw unit would suffice, if not, a 4Kw unit might be more the requirement. I have on occasion seen the state of the power demand on marinas when people are tinkering on their vessels in the winter - 300 amps per phase is nothing when people turn on heaters. And that is not in a large marina. Scary stuff!.
  23. BP, have you ever had your yacht on a marina and used domestic heaters to keep warm whilst on board in the winter? A large domestic fan heater maxes out at 2.4KW. As a guide, on a 45' we find that an electric fan heater on high for about 10 minutes brings the cabin well up to temperature, then we turn it onto low which at worst maintains the temperature even with 3 or 4 degree outside temperature. Translate a moderately roomy 45' cabin into what you have, and I strongly suspect that whilst you would get a moderate amount of warmth out of a 2KW unit you will be unable to warm the entire vo
  24. too_tall

    Kaikoura Wharf.

    My 3 year old can act more maturely than some around here!. Shane is free to do as he pleases. Hopefully he has listened to those who have told him not to try going into Kaikoura. Specially with more recent events effectively turning that area into an uncharted area. He has to learn somewhere. As Wheels said, its not the unforgiving coast that some can be ( and hopefully Shane realizes that the coasts anywhere, at any time, can be totally unforgiving and treacherous ). He pottered around the Hauraki Gulf and the Coromandel Peninsula by the looks of his prior posts, probably time t
  25. Shane, don't assume that a marina with berths that have no vessel in them means spare berths. If those berths are owned by someone, or, leased to someone, they can't just put another vessel into those berths as if the rightful owner or lessee returns to find it full, they will be more than a little unhappy. There are also other protocols which must be followed - I know that most marinas I have been into require significant public liability insurance cover for vessels, in case you run into one or a number of other vessels, or, if your vessel sinks or in some other manner causes a significant po
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