I noticed a comment on yesterday’s blog entry that just says “Why was this boat made so complicated?”
That seemed a good topic for today’s blog entry.
First, I should remind people. When posting comments, PLEASE give me a name to respond to, even if it is a made-up name. That particular message shows as having been posted by “unknown”.
Anyway, I’ll begin my response by a comment I hear frequently from Roberta that has nothing to do with boating: “Why is it that I can never figure out how to use the TV?” Our television at our house here in Cabo has multiple video sources; the security cameras, the satellite television, the Kaleidescape video jukebox system, the Lansonic Audio jukebox system, the DVD player, the ipod interface and a bunch more. We have remotes with color screens on them, and you have to begin by deciding what you want to watch, and then selecting the content you want to view. It feels natural to me, but VERY unnatural to Roberta. What she’d like to see is a television that just allows you to flip through the channels to decide what you want to watch. Whenever she wants to watch TV, I have to work the remote.
Even cell phones are getting complicated. I have an iphone and last night at dinner, I was explaining to Roberta that I was rebooting it, because it had hung while checking my email. She looked at me like I was from another planet. “Why can’t you just have a normal phone?”
Simple things are simple to operate and maintain. Complicated things are complicated to operate and maintain. If I wanted a television that would “just allow channel swapping” that would be simple. I wouldn’t have or need any of the other gadgetry. If I wanted a phone that “just calls people” I wouldn’t have one with built-in email, contact manager, web surfing and more.
In other words, it is I who control the level of complexity that I want, by deciding what I want to be able to do. If I want to do more, it comes at a price (purchase cost, effort to use and effort to maintain).
And, to return this discussion to boating…
It is possible to construct a very simple boat. I was on a Nordhavn a few months back where the owner ordered it with only a single engine, no thrusters, no wing (backup) engine, no sat tv, minimal electronics, and no opening windows. You can bet his operating manual is smaller than mine.
My boat is more complex than most, because I ordered it that way. There is very little on my boat that I couldn’t have lived without. Let’s pick one of the more obvious “extravagances” – the hot tub. Something that is nothing more than an “outdoor bathtub” added a layer of complexity to the boat. To have the hot tub, we had to figure out how to heat it. This means wiring for electric heat. In my case it also means a diesel furnace, plumbing and a heat exchanger, all of which have to be maintained.
There are a lot of Nordhavn owners who are on their second or third Nordhavn. One reason is that no matter what equipment you choose, an hour after taking delivery of the boat you start seeing things you would do differently if you “had it to do over again.” Fortunately, Nordhavns have had a good resale market, and have held their values well, so more than one owner has yielded to the temptation to start over with a blank sheet of paper.
Now that we are one year in, and have 10,000 miles on the boat, I am taking a hard look at the boat and asking myself what I would do differently. I absolutely agree with the person who said “Why was this boat made so complicated?” But, the only way to reduce complexity is to reduce features. Would the boat be simpler without the diesel furnace? Sure. Would it be simpler with only one engine? Sure. Would it be simpler without the six ways I have to get to the internet? Sure. Do I need inverters at all? Perhaps not. Could I survive just fine with one generator? Probably. I can play this game for a month, and there’s almost nothing on the boat I can’t eliminate and render the boat simpler. Heck, some boats don’t even have motors, they just hang up a sheet and go where the wind takes them!
So.. the bottom line is that the boat is complex, because when I designed the boat, I took about every optional feature Nordhavn offered, and then added a bunch more that weren’t on the price list. With respect to my particular boat, we had a rational reason for doing this. Over the next decade, we will be circumnavigating, and wanted to be as comfortable, and as safe, as possible.
“We wanted a boat capable of being run by two persons, that was as comfortable as a five star hotel, with full redundancy for every system, and we wanted it to feel at home on every continent.”
Hundreds of people have navigated in simpler boats. Row boats have crossed oceans, but then, so have mega yachts. Each person has to look at their own budget and tolerance for discomfort and decide what is right for them. I look at someone traveling around the world in a 200+ foot motor yacht, with a crew of 20, and raise my eyebrow, the exact same way many sail boaters raise an eyebrow when they see us come rambling into a marina.
And.. to return to the inverter topic… which dominated the last few days postings…
Although there is not 100% agreement, I have decided that I am positive that Mr. Jones was (and is) wrong, and I do in fact have 14kw of inverter capacity, at 240 volts. I’m currently in Cabo, and the boat is in Seattle, or I would do some testing to prove this. As a few of the comments on the message board said, my 240 volts is split into two 120 volt legs, which can be used independently, or combined, to get 240 volts. I have something called a “balancing transformer” that monitors the electricity on the two legs, and helps distribute the load between the two legs evenly.
There are still things about the inverters that confuse me, and my hope is that my recent education in electricity has given me the foundation for studying the plans and making sense of them. I operated my Nordhavn 62 for nine years with almost no understanding of any of this, so I’m hoping that people reading this aren’t saying to themselves “Owning a boat sounds complicated!” That’s not really true. I just made the decision that if we were going to circumnavigate, then I wanted to know how every system on the boat works, because calling a repairman, when anchored off an Indonesian island, isn’t always easy.
-Ken W
11 Responses
Ken:
A logical extension of the complexity/simplicity debate maybe to consider in a formal way what is essential to boat operation and safety (engine(s)and navigation) and what is nice (A/C, etc.) and then separate the operation of these systems as much as possible. Contingency planning, training, maintenance, spares would then be weighted towards the mission critical system(s). I cannot imagine you not having thought along these lines but having formal written procedures could save a lot of time in critical circunstances
N4061: Thanks for the referral. I downloaded the song on Amazon. I’m not a country fan.. but, I’m certainly a Cabo fan! Maybe he lives here somewhere… I do like the song, so maybe I’ll give his music a try.
A side-story about Cabo. We just had a Nordhavn owner here (Eric, Annie and Bear Bloomquist, N6409). They were headed for La Paz when I started lobbying that they should come to Cabo instead. I always think that Cabo has a bad, and undeserved, negative reputation amongst cruisers, so anytime I have a chance to show a cruiser that Cabo is much different than its’ reputation, I kick into high gear.
There are two cabos (Los Cabos); Cabo San Lucas, and San Jose Del Cabo. As a resident, I think of Cabo San Lucas as “the tourist town” and San Jose Del Cabo as “the real town.” Because the marina in San Jose is new, most cruisers don’t really know San Jose.
The Bloomquists were scheduled here for two days, and stayed a week. I’m not sure what perception they had of Cabo before, but I’d be surprised if they pass by in the future without stopping in.
One negative on San Jose though.. The marina, Puerto Los Cabos, is in the boondocks. It’s only a mile into San Jose, but it isn’t realistic to walk it. With a rental car, you are in a great place, and without, there is nothing to do.
-Ken W
Ken, this may be slightly off the subject but since you live part time in Cabo (a place we have visited many times) i thought you may apprecaite a song that was just released by Toby Keith called Cabo San Lucas. I’m not a country fan myself (Jimmy Buffet excluded) but it is a good song for Cabo.
JohnA is correct.
Kent, your electrical engineer is wrong.
Without a load balancer, Ken could support only 7kw on each 120v leg, and conceivably could trip a circuit breaker pulling 7.1kw if loads were not balanced across the two legs.
However, when running 240v appliances, all loads will be balanced across the two legs.
Ken, you have 14kw of power. You’ve been correct all along with;
Power = Current * Voltage (P=IV, Watts = Amps & Volts)
Circuits in parallel will add current, while keeping voltage constant.
Circuits in series will add voltage, while keeping current constant.
You can support a 14kw load.
You are also correct on horsepower. 1 Horsepower is defined at 745.7 watts.
-Bill
(has an engineering degree)
Sorry to get off topic. I posted a link for a product that controls intake strainer growth a week or so ago and read that someone was unable to find the products on the http://www.rgf.com (http://www.rgf.com) website. Here is the .pdf of products they make for marine use.
http://rgf.com/documents/Ma… (http://rgf.com/documents/Marine_product_list.pdf)
Some are mega yacht stuff but others I believe I would want in my house. I sell these products that they make for indoor environments, not marine. I just happen to have the catalog for all. The technology is rigorously tested. China bought hundreds of thousands of this tech after the SARS outbreak. The idea of controlling growth in a strainer or piping system is no different (well some differences) than a air/surface space. I ranted for long enough, the website explains the details precisely. Love the website Ken, missed you in Alaska but what a beautiful place. Good luck on your Japanese adventure.
Again I agree with JohnA and would remind doubters that we are dealing with alternating voltages and currents. The voltage on line L1 goes from +120 volts to -120 volts 60 times a second. The two pairs of inverters are arranged so that when L1 is +120 volts, L2 is -120 volts. The voltage difference between L1 and L2 is thus
(+120) – (-120) = 240 volts.
Moving on and looking at your inverter wiring diagram it would seem to me that the balancing auto transformer is the Achilles heel of the system. When the system is supplying very little current only the master inverter will be on. Small loads on L2 and across L1 and L2 will be feed by the balancing transformer.
When a large startup load of 50+ amps occurs the balancing transformer will try to accommodate the load until the other inverters switch in. The transformer is protected by 25amp circuit breakers, whether they would trip on 50+ amps is any ones guess, but if they do then that would delay the startups progress leading to failure.
I think your soft start chiller will a move in the right direction.
Wow, simply amazing that alledged electricians and electrical engineers have no understanding of electrical circuits!
They keep talking about legs as if they were seperate things. Guys, you need two legs to complete a circuit (one may be a neutral, I’ll get to that later). Using Ken’s correct calculations and his supplied diagrams – between outputs L1 and L2 we have 240 volts. At full power draw that gives us about 58 amps current. Now surely, all you electrical experts must know that in a complete AC circuit (or DC for that matter) both legs must be carrying that 58 amps.
So, if we put a 14KW motor in that circuit between L1 and L2, it will use all 14kw of supplied power, no more no less.
Now let’s introduce the neutral leg which divides the voltage. L1 to neutral we have 120 volts and L2 to neutral we have 120 volts. Are you with me?
Okay, let’s put a 7KW motor on the L1 side and see what we have. Surprise, we’re drawing 58 amps, but at only 120 volts so we’re only using 7KW. Forgetting Ken’s balance transformer, the neutral leg also carries 58 amps since the L2 side is not loaded in this example. Again, a complete circuit with each leg carrying the same current.
Now, if you also load up the L2 side with a 7KW motor, then both L1 and L2 will carry 58 amps and the neutral 0 amps. A complete and balanced circuit, baby! This is absolutely no different in power draw than in my first example of a 14KW motor connected between L1 and L2 with no neutral.
Load up the 120 and 240 volt circuits as you wish, you still have 14KW total available power. No amount of faulty logic will change that.
Kent: I don’t know that I understand what you are saying… If I have 14kw of total capacity, at 240 volts, then I should be able to power a 14kw motor. It would naturally pull 7kw from each leg. That said, electric motors have special needs. They normally have materially higher starting currents. A 14kw motor might very likely take 25kw or more to get rolling, then the ongoing demand might only be 14kw.
As a side note: there is a correlation between kilowatts and horsepower. A 14kw motor can also be described as an 18 horsepower motor. It takes around 750 watts to produce one horsepower from an electric motor. Notice that voltage is not mentioned… The formula for determining wattage is: volts times amperage. So.. a 1hp motor could be powered by 24 volts, at around 35 amps, or by a 240 volt motor at 3.5 amps.
-Ken W
I was talking with one of the electrical engineers at work about your question. He said that you have 14 kw of total capacity but cautioned that you can only support 7kw per leg. He explained that 240 volt equipment is rated to draw the full load from both legs. So a 14kw motor will draw 14kw from each leg. Based on his explaination you can only support a 7kw 240 volt piece of equipment.
Thank you Ben! And… don’t give up on buying a Nordhavn. With some hard work, and a couple lottery tickets, who knows?
As to the appearance of the N68… One of the interesting side stories is the begging that we had to do with Nordhavn over the extended upper decks. Our favorite place on the N62 was always the little deck behind the pilot house. We found that it was a great place to hang out, and stable even in rough seas. We felt that by extending the deck it would give more square footage, plus provide shade to the cockpit, and the extended fly bridge deck would give a lot more space to the fly bridge (that we’re using for the hot tub). I agreed with Jeff Leishman that it “hurt the boat’s lines.” I’m jealous when I see how clean the look is for the 76 and the 86, but there’s no way I’d give up all the great exterior decks we have.
As to my former company: Sierra… I can’t take credit for Diablo. That was a competitor of ours. We did have our own online games network, called The Sierra Network (TSN), that we later renamed as “The Imagination Network.” We sold a lot of different games, but are probably best remembered for games like: Kings Quest, Phantasmagoria, Leisure Suit Larry, and Half-life. Roberta and I had Sierra for over 17 years, including seven or so as a public company. I hated the non-stop pressure of running a public company, and was more than happy to retire when the time came. Cruising the Bering Sea might be risky, but it’s unlikely to be nearly as tense as those quarterly investor conference calls!
Thank you for the support! – Ken W
Dear Ken,
I am sorry I don’t have an answer or even remote suggestion as to an answer to your electrical issue. I just wanted to thank you for writing your Blog and maintaining your website. As someone who yearns to own a boat and see the world, but also realizes I can never afford it, I very much enjoy reading all the information you post.
Your yacht is perfect in my opinion as far as size and appearance as to what I would want in a yacht. It is the best looking Nordhavn I have seen. Even the 86’ in my opinion is not as desirable as yours, mainly because I would want to be able to cruise the world with my wife by ourselves as you and your wife do. The physical appearance of the 68’ is quite an improvement over the Nordhavn 72’ & 76’ models. I definitely like your choice to allow access to both sides of the boat for docking.
With even the Nordhavn 47’ being a pipe dream, I enjoy imagining what it is like to own such a vessel through your writings. I can’t believe how you find the time for everything you do.
I must mention I believe I read you were the founder of Sierra Online gaming. I believe I played a game on that network back in the late 90’s early 2000’s, possibly Diablo? I don’t remember much about it, but I enjoyed it, probably why you are where you are and I am dreaming of doing what you are.
Best of luck on your trip to Japan. My hopes and prayers go with you and your wife on your journey.