Questions About Sailboat Electronics & Software
Index
Keeping Time
Radar Scanner Position
Forward Scan Sonar
Navtex Receiver
GSM Phone
Keeping Time (10/2009)
Question: What do you use for time keeping at sea? If you use a wristwatch then which one?
Answer: When this question first appeared in our In-box, I wrote it off as too basic to answer in a post; however, upon reflection (actually, John pointed it out!) I realized that there really is more to our choice of time keepers than first meets the eye.
There are a number of features that we won’t do without:
- A large enough digital readout that we can see the time with our middle-aged eyes, even when we are tired and/or in dim light.
- Really good back-lighting, so that we don’t have to turn on a light or use a flashlight to see the time during night watches.
- An alarm that is loud enough for us to hear with our middle-aged ears, especially when we are dressed for cold weather with a watch cap and hood on (actually, this is becoming more of a problem all the time as we both get deafer).
- A timer that is easy to set, start and stop for use in tracking radar targets (we set the timer for 6 minutes, mark a target's position at the start and again when the timer goes off, and multiply the distance by 10, giving us our relative speed in knots).
- Two time settings so that we can keep one on GMT and change the other depending on our location.
- Easy to manipulate buttons, for when it’s cold and we have gloves on.
- Water resistance, for reasons that should be obvious!
Looking at that lengthy list of requirements, I wouldn’t
blame you for expecting our time keeper of choice to be an extremely
expensive watch advertised in glossy magazines by the likes of André
Agassiz; however, we (and our banker) are happy to report that it’s a
lowly Timex
Ironman 30 Lap that retails for a whopping $35.00
(at discount),
costing us a total of $105.00 when we buy one for each of us, along with
a spare.
I don’t mind being particular as long as it only costs us $105.00, but don’t get me started on how much our pickiness regarding foul weather gear costs!
Reader Comment:
I would add to your requirements: Analog hands with
glow in the dark feature so it's easy to read the time at a glance. My
IronMan is 4 years old and has hands as well as digital feaures.
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Radar Scanner Position (04/2008)
Question [edited for brevity]: What is your preference regarding the best place to mount a radar antenna? As far as we can tell from the pictures of Morgan’s Cloud you have mounted yours on a pole aft.
Our previous experience with radars tells us that the antenna should be as high and free as possible. Wouldn't a radar antenna mounted on the mast just above the first spreaders give better range and a more detailed radar picture than if it were mounted lower?
It also appears from the pictures that your antenna isn't mounted in a way that makes it able to tilt so that it can compensate for heel of the boat when sailing.
Answer: First off, we should say that we view radar as the most important piece of electronic equipment on Morgan’s Cloud—yes, more important than GPS, since we can find our way with a compass and sextant but we can’t see unlit objects at night or through fog—so we have given a lot of thought to the position and installation of our radar scanner.
We prefer a pole mounted aft for the scanner over mast mounting for the following reasons:
- The scanner is much less vulnerable to damage from an errant halyard or sail.
- We do not agree that a higher position for the scanner is a significant benefit. Small targets, like buoys, don’t show much over a mile regardless of scanner height and large targets, like ships, show at 10 miles—plenty of room to plot and take avoiding action—with our current scanner height. In fact I think that putting the scanner substantially higher than ours can be a disadvantage since it will be subjected to more motion in a seaway.
- A scanner on the mast is more difficult to service than one on a pole and heaven help you if the cable needs replacing.
- Mast mounted radars are very vulnerable to damage when the mast is un-stepped.
- We don’t like the added weight aloft. Sure it’s not that much, but with the lever arm, every pound counts.
About the only advantage I can think of for a mast mount would be a theoretically less impeded view forward. However, in the real world we have never found that there was any appreciable radar shadow cast by the mast and rigging.
Our radar scanner can be inclined to compensate for heel using a clever system based on a speedboat hydraulic trim tab pump and actuator. We got ours from Edson, although a reasonably handy owner could duplicate our system, by buying the gear directly, for a fraction of what Edson charges.
We would not be without this tilt feature since it is just plain dangerous to sail around with a huge radar blind spot on either side of the boat when heeled. This was graphically brought home to me the second year I owned Morgan’s Cloud (before we installed our incline system) when we were nearly run down in thick fog by a trawler that we only saw at 100 yards and that visually, not on radar, approaching from our port beam. Yes, I know we had the right of way, but with huge steel trawlers traveling at 10 knots that is scant comfort!
Incidentally,
we far prefer our manually controlled (using a switch in the cockpit) inclining
system to gimbled backstay systems like the Questus.
Our thinking is that no matter how well damped the latter is, there are
just too many bend cycles being put on the cable. Also, back stays are
prone to vibration, surely not a good thing for sensitive electronics.
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Forward Scan Sonar (2006)
Question: We are looking at sonar options for use in areas with poor charts and low visibility. Our interest is primarily for checking anchorages and narrow passages, looking for obstructions. We have a small plotter/sounder in the dinghy, but nobody wants to go out in the dink when it is cold and rainy (and warm and dry on the big boat!).
I have heard a rumor that you guys have an EchoPilot unit:
- How do you like it and how does it work?
- What do you do in a tight anchorage for checking what is around you?
- Is there a problem crossing your own wake at dead slow speeds?
- Where have you mounted the transducer and is it vulnerable to ice and debris? In our case, it would be on center, 16' aft of the bow (in our forward watertight compartment) or centered fore and aft, offset to one side about 5' and alongside one of the stabilizer fins (which reside in sealed coffer dams).
- Have you used it in the tropics with coral? I assume it would work well with the abrupt shape of the coral heads.
- Can you tell anything about bottom composition, i.e. mud vs. rock or kelp?
- Is it any good in ice?
- What do you do for a depth sounder? Use this, or something more specialized?
Answer:
- We have EchoPilot's first model, the FLS II. See Stuff That Works for our experience with it.
- We scan most anchorages for obstructions with the FLS II prior to anchoring and frequently explore totally uncharted narrow passages using it. You do need to keep in mind that although it will look out 200 meters in deep water, the forward distance that you can practically resolve an obstruction at is limited to about three to five times the depth of the water. Therefore in water 5 meters deep you are only really looking out 25 meters, at best. So in shallow water you need to move very slowly with someone glued to the FLS screen juggling the range to make sure you will be able to stop before hitting something.
- Yes, you will get interference from your own wake, although we have never found it to be a big problem. A larger issue is that if you reverse hard your prop wash will shut the system down completely until the wash clears. I suspect this would happen with almost any system.
- Ours is further aft than yours, almost amidships (an EchoPilot recommendation, to keep it away from bow wave turbulence), and next to the keel. We have had no problems, even in ice. I’m no expert, but I would worry about having it on the center line without keel protection. I would guess that the aft position next to the fins might work better from the protection point of view. The only thing that I would worry about here would be turbulence from the fins, but you would know better than I what the situation is there. Our transducer is quite close to the keel root and we have no turbulence problems. You may want to talk to EchoPilot about the forward position and see what they think. The good thing is that the transducers are built to sheer off at the hull if hit, so there is no potential damage problem, and a spare is easy enough to fit. You should carry a spare anyway as the transducers tend to lose sensitivity over time. They seem to last us about two years.
- No, we haven't used it in the tropics but it resolves boulders on the bottom of arctic anchorages well, so coral heads should be no problem. Vertical face obstructions like boulders and coral heads are what it does best.
- No, it does not tell anything about bottom composition.
- No, it is of no use in ice. Some years ago EchoPilot announced a high end unit with gyro stabilization capable of detecting a container at sea, but quietly withdrew it after several years of development. I spoke to the owner of EchoPilot and he said it was just too difficult to get stable and would have been hugely expensive. Bottom line, this technology is hard to do well. I think I’m right in saying that most other products are based on fish finder technology and that EchoPilot are the only ones to start with a blank sheet of paper and design a forward scan sonar. Bottom line, they are the product to beat.
- We also have a depth sounder since the
FLS II numbers are hard to read, it has no surface offset function
(fixed, on later models) and we don’t trust it to read accurately down
to a few centimeters as we sometimes need to do when calculating whether
we will bottom out on a low tide. The challenge is that you need to
get a depth sounder that does not operate at 200 KHz, or it will interfere
with the EchoPilot and vice versa. We solved this by getting a smart
depth sensor from Airmar that works on 175 KHz, designed for fishing
boats with fish finders. Also, B&G sounders operate at 175 KHz.
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Navtex Receiver (2006)
Question: I'm planning to purchase a navtex receiver (NASA model, made in UK), so your comments about your experiences with navtex [see Stuff That Works and Gear Failures & Fixes] captured my attention. I wouldn't want to purchase something that didn't have a good track record where it counts. We considered the Furuno, but based on [magazine] reviews, the NASA model would suit us OK for size, power consumption, dual frequency, etc. Of course, if this is the brand that proved unsatisfactory for you, then I'd sure like to figure that experience into my purchase plans.
Answer: You are safe! It was not a NASA model navtex, but an ICS. We don't have any information on the NASA, positive or negative, but would be interested in hearing your experience with it since we are often asked about navtex equipment.
While we are not sure of this, it is our guess that part of the secret of good navtex reception is in having an active (preamplifier in the antenna) antenna rather than passive, although the ICS did not work well with either for us
A potential drawback of magazine
reviews is that the authors very rarely have real experience with the units
offshore and so they tend to concentrate on features like where the buttons
are and what they do, rather than actual functionality, as in does it get
the information you need.
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GSM Phone (2005)
Question: I recently purchased a GSM phone for when I travel on business and pleasure to Europe and Asia. I am in the importing business and I am tired of renting GSM phones. What interests me is how do I arrange in advance the software and Sim cards for say Hong Kong, so that when I am there, I can get my e-mail as well as use the phone for calling etc? For your reference I have the cable to connect the phone to the laptop, and the software I believe is subject to the provider I will use. Since I do not have GSM service here in the US, I do not have software for the GSM phone. Anyway, I am interested in how you go about arranging for the particulars regarding the service and software.
Answer:
- The software to drive the phone needs to come from the phone manufacturer; in the GSM world it has nothing to do with the network you use. I suggest you check the manufacturer's web site.
- A GSM phone bought in the USA may or may not be compatible with GSM networks in the rest of the world. (The USA uses a different frequency.) Unfortunately, just another time when a 'standard' isn't.
- The best way for you
to get up and running, at least initially, is to buy a 'pay as you
go' kit in a GSM country.
This will include a SIM card for the network that will plug into the
phone and a card good for a number of minutes. You can get them at
any phone store in most European countries; I don't know about Hong
Kong.
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