Tag Archives: Technology

Sneaky Amps

IPNRight after we installed the satellite TV antenna, we spent several days metering what it meant to us in battery consumption. The antenna and receiver are both 12 volt DC. The number we got was a bit steeper than we hoped for, but not outrageous.

And it was wrong.

Day before yesterday, I noticed all the status lights on the navigation laptop were off, and I knew we hadn’t shut it down. This is a ten year old IBM x40 Pro*. Given the way it has been treated, 10 years seemed a bit soon for it to drop dead, but it’s tech, so there is always the random element. The light on its 12 volt DC transformer/charger was on.

Then I noticed the router, which is on the same bus as the laptop, was frozen in stand-by mode. I touched the laptop transformer…and immediately unplugged it. It wasn’t, “melt things hot,” but it was too warm. My first thought was the after market battery in the laptop had failed.

I fired up the laptop using the 110 v AC charger and the battery was at 2.5%! Yep, failed!

Nope, it immediately began accepting and holding a charge. (Well, at least as well as it had been. Not all after market batteries are created equal, and this one is five years old.)

Apparently, the DC charger failed the day we fired up the satellite TV for the first time. Prior to the satellite TV installation we would have an early morning dockside deficit of about -50 to -60 amp hours (aH) (starting from zero about an hour before sunset). With the new TV antenna-receiver in use this had increased to -80 to -90. Like I said, not great, but not impossible. I attributed it to boat movements driving antenna realignment.

What I know now is the the laptop DC transformer shorted internally. With the laptop now charging off AC, our morning aH deficit is back where we expected it to be, about -5aH more than it used to be.

Clearly at anchor it will be greater than that because more antenna realignment is required.

So once again a battery charger failed us, and I am reminded that once again I need to check current draw on an item by item basis more often than I have been.

We ordered a new charger and will evaluate it here at some point. The ordering process was certainly easy.

*Reading this old x40 review with the current state of the art for digital devices in mind leaves me wondering just how much will things change in the next ten years?

The Sandy Boater’s Guide

SandyOne reason we didn’t go up to Maine this year was the post-Sandy conditions in the ICW and offshore. Stories we have heard have left us feeling good about the decision. Now, BoatUS has reported an app has been developed to help people deal with the very fluid situation surrounding the restoration of services and waterways. The Sandy Boater’s Guide links are at:


Like all technology, it’s a tool, not a panacea.

Give Me Liberty (Ships)

From 1943-45 Brunswick built Liberty Ships. My Dad’s parents built them too — up in Washington State.

Below is an aerial shot from The War showing the yard. (linked)Liberty B&WThis is the current aerial of the same area,Modern Brunswick

This is the merge of the two, (1945 shot colorized, click for better resolution)Overylay

Out near where they hold the Farmer’s market ( a half mile walk) is a model of one of those ships that helped win The War.Liberty Ship Mon

The Digital Library of Georgia is part of the GALILEO Initiative
© 2005 Digital Library of Georgia

The Sands of Time or the Time of Sands (not the beer)

Moving SandRecently a sailor asked why he didn’t see any people anchored off the beautiful beach at Treasure Cay — the chart showed good water. We just responded go to Google Earth and see what the sand bores (not bars, here) look like. Just a few weeks later Google introduced Google Earth Engine. It’s a 1984 – 2012 time-lapse of planetary changes captured by Landsat.

To see what we mean, go to the link above and type “Green Turtle Cay” in the search box. Look in the regions we have highlighted with arrows, and you will see why charts are guidance, not flattened reality. Just go to full magnification, shift the image up and to the left and watch the sand off Treasure Cay writhe (yellow arrow area) and Green Turtle Cay grow to the SE (red arrow area). We would have provided a direct link to the imagery, but the Google Earth Engine doesn’t support that.

NMEA Pro Omnibus — $15U.S.

We have all our navigation equipment at the pedestal except for AIS (Vesper Marine)  and XM Satellite Weather. Both devices output data via USB. For about $300 we might be able to port the AIS data directly to our pedestal via our Ethernet backbone. However, we’d need an additional $500+ display as the chartplotter is nine years old, and is set up for MARPA. AIS was not broadly available then. There is no room at the pedestal for another display even if we could get the data there.

AIS Display


Another $300 might be required to multiplex this AIS NMEA 0183 data stream at 38400 baud with the NMEA 0183* data that already flows on the Ethernet backbone at 4800 baud. This might or might not work (The multiplexer device tech data says yes, users have told me sometimes.).

The XM data format is proprietary, and next I’ll be trying to figure out how to port it to multiple devices. It isn’t essential to do so since it is a long baseline planning tool — except when doppler radar loops are involved.

We were disinclined to spend ~$600 on a maybe solution.

As a result of our need, then desire, to stay connected, we have second backbone. It is wireless. We have a boosted antenna on the davits connected to a USB-powered router below — any wireless enabled device on the boat, laptop. reader, smartphone (cellular off) can connect from anywhere. So the challenge became to move the AIS data/information to the cockpit at low cost.

Wireless AISStep one was to move the USB delivered NMEA data to the wireless backbone (using TCP/IP). This requires a server — it’s what servers do. We already had one. It is part of the Rose Point Coastal Explorer software. But this software is a memory hog on the 12 year old IBM X-40 I use in the nav station. I didn’t want to have it running because it interferes with the weather software smoothly updating. So I found GPS Software for Google Earth — by Greg Heppenstall. $15 via PayPal later and I had a smoothly functioning server on the X-40 and a similar client on the environmentally protected laptop in the cockpit.**

Because I also use a piece of navigation software that can only accept NMEA 0183 via a COM port, we needed to find a software solution for binding a virtual comm port on the cockpit laptop to the wireless backbone. I found the HW-VSP3 software (free for single port, personal use).  While this must be reset each time it is used, it takes seconds, and free is a good price for something tested in a demanding market.



So now all our AIS data/information and anchor watch data is available anywhere on the boat*** as long as the router is functioning. So it’s time for a spare router ($19 when we bought the first one, now $27. Still a bargain).

Total tab with spare router = $42. Much better than $600.

*Yes we know, NMEA 2000 has arrived. But it is expensive to retrofit, requires special cabling and connectors, and is aimed at a segment of the market that needs its feature set — we don’t, and a huge number of boats never will, and NMEA 0183 will hang around for decades.

** We are not fans of smartphones or tablets in sailboat cockpits. For those who navigate from environmentally protected spaces and who have the time and navigation space to squint at tiny screens with sun dilution, they may be useful. Having said that, when in network coverage, we have benefited from these devices (mostly doppler radar displays). We just have no interest in relying on them or making them the centerpiece of our situation awareness. If others want to use them, fine, as long as they don’t contribute to accidents.

***Even the TV, as it can be connected to the laptop via HDMI or S-Video, and we are looking at how to port low data rate imagery (weather and nav) to the TV via wireless. Also, since we have the boosted antenna on the boat, it may be possible to get the AIS/Anchor watch data to a portable device when we leave the boat.

70 mph* at the End of the Dock

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We are at the right hand paddle. Times are GMT

At 0215 EDT (0615 GMT) this morning we got clobbered — lightning, thunder, wind, rain and hail (though not much of the latter). It was well predicted, but hard to track. U.S. Doppler radar coverage doesn’t quite reach here. But these systems arrive like big logs rolling down a hillside. When you see one coming, you duck. Sometimes they bounce your way, sometimes they don’t. However, satellite imagery can offer some help. In the graphic above, blue clouds are warm and near the surface. Orange ones are very cold and tend to represent the tops of major storm cells or clusters of them. You can see why at 2300 last night we were thinking about doubling the dock lines. The storm that did hit us (22 minutes after the red framed image) doesn’t even show up here. But still, we knew the big log was rolling down on us. For once, being surrounded by breeze killing walls of large powerboats seemed like a good thing.

*Unlike 70 mph winds in a hurricane, these downburst gusts lasted a few (very long) minutes. This is our fourth experience with squall winds of this speed or greater in two years. Last year, a line like this one (about this time of year) just missed us at Green Turtle Cay and clobbered Great Guana just to our SSE — 70+ mph were recorded at Fishers Bay. The lightning looked and sounded like a Russian artillery barrage.

In June, a derecho hit us off Altamaha Sound (Georgia) where we recorded two gusts of 69 knots (80 mph). The NWS data reflect gusts of 62 knots  inland, but these things speed up over water. Then barely a month later there was the Washington DC derecho that hit us at anchor in West River — and again NWS recorded gusts were between 80-100 mph within a quarter mile of our position, but we only saw 85 mph.

Before that it was 1975…

…when God’s refrigerator door opened on us in a club-level ocean race from Port Canaveral to Fort Pierce. The temp dropped 20 degrees in less than five minutes. Air that had been lifted over Florida for an entire day was pushed east by a front, and then it fell back to earth in a single massive waterfall of air — its velocity added to the front’s. That was at night, under a dome of absolute black, under full sail on a prototype racing boat with an inadequate rudder (we found out a few moments later). All we had for weather warnings were lightning flashes and the roar of wind which could be heard far enough ahead of its arrival we were able to get the sails down before it rolled us. Those gusts were only 65 mph according to the USAF.

Five episodes in 39 years of sailing around 25-35K  miles (who keeps count?) near sub-tropical land. Not too bad, but we’d be happy to let someone else have our turn next time.