Wiring & Radar Installation on Deck-stepped Masts

George B., s/v Freya · Mar 9, 2006

Great Fun

I understand the use of hyperbole to drive home a point, but really. Let me get this scenario straight. Somehow, I find myself sailing Freya in a sea state higher than my LOA, in a full gale, dodging freighter traffic that is using only 1 – 2 NM separation? Am I sailing in the Straits of Malacca during a building typhoon? And if so, am I also fending off pirates? Any wave strong enough to snap a SS pole or rip out through bolts will be strong enough to break the coax antenna cables and the 14 AWA wires attached to the antenna. Any wave strong enough to carry away a radar pole will probably carry away the helmsman too. So far, this discussion has been focused on the general physics and perhaps we can move on to specifics, like power, accuracy of the receiver etc? What type of transmitter are we talking about? The power of a 2KW transmitter is pretty dispersed and weak by the time it hits a target 40 miles out and chances are the return signal won’t be strong enough for the receiver to recognize it. I’ve been told by several sales reps that the effective range of the unit is much shorter and you should be using the 20NM range as your max setting. For me, that means there isn’t much difference between the mast or pole mounts. To get longer effective range, you need to step up in power (4KW) and/or go to the external beam type antenna (greater efficiency). IMHO, neither is a practical solution for one simple reason. Whereas you may be using radar a few times a year (I sail foggy San Francisco/ N. Cal), the mounting is up there all the time. A pound aloft is equal to ten (or more) pounds on deck, so you loose some of your boat’s stiffness mounting the unit high. That antenna and it’s guard really fills in the fore triangle. My genoa used to get hung up on it all the time. That especially bugged me, and my next radar will be a pole mount.In high sea states, the boat is obviously going to pitch and roll a lot and you will be getting a lot of radar reflection off of wave tops which will inhibit your ability to see targets of interest. The sea state control will filter this out, along with those targets of interest. Patrick is right, when sailing in high sea states and full gales, the effectiveness of our little 2KW sets is going to be greatly diminished.

patrick · Mar 9, 2006

Thanks, George

Your points are right on except the conditions do happen to exist right in my back yard. Yours too if you go offshore a few miles. I have personally seen them a few yrs ago. The weather went from nice and sunny to horrible in a matter of hours, we were 60 or so miles offshore and there was nothing we could do to escape that. It was not my choice to go on but it was not my boat eitherOur radar was mast mounted and I am very glad it was for all of the reasons I stated. I remember looking up from the helm and as we topped the crest of a wave, there was a freighter just a few hundred yards away. It was only possible to see it when both vessels were at or near the top of a wave and that was not often. I called them on the radio and they answered in Portuguese or something but at least they knew we were there.I say we but the fact is that the owner of the boat went below and would not get out of his bunk for over 30 hours of this storm.The radar had given an intermittent indication of the freighter but it was very rough and it was not possible to watch the screen for long. I found that anything which required me to focus on close up data would make me sick.I have seen radar poles which were knocked down or bent by the wind. They get installed by idiots in fair weather and so no one thinks about it until it breaks and that may be when you need it most and it becomes a huge danger to the boat and crew. The scanner cable is pretty strong so my guess is that it would not snap easily.Read the article and note the use of radar to assist with navigation even in good weather. If it can see 15-20 miles, that is a lot of help at times. You said "The power of a 2KW transmitter is pretty dispersed and weak by the time it hits a target 40 miles out and chances are the return signal won’t be strong enough for the receiver to recognize it. " My experience says that targets of interest at that distance are fairly big - freighters, water towers, small mountains, and even fairly small targets will give a useable echo. Fred has jumpered the rep rate generator in his 2kw unit and he claims to see targets at 40 miles if I remember correctly and his is on a pole. Is that right Fred? I think we had that discussion long ago.The main factor for absolute range is the antenna design, gain, size, etc. and the sensitivity of the receiver not the transmitter power. The power output is usually increased for longer range designs but is not really as important as the antenna.Altitude is the biggest friend you will find in a radar installation. It will give you significantly increased range and target discrimination and does not reduce close in sensitivity as has been asserted. My experience says the close in sensitivity is better on my mast than on a pole. Gimbals help a little but add another thing to fail for not that much benefit and they are costly.

patrick · Mar 9, 2006

Barry, as to connections

I have had good luck with some units by disassembling the molex connector, fishing the cable, and then reassembling the connector. It is not too mechanically difficult but you will need to very very very carefully label the wires as you take it apart and make absolutely sure to put them back into the proper locations. You need to be careful not to damage the metal contacts of the connector when you fish it, too.I do not know if you have a section in your mast for wiring but if you do, you should be able to install the radar ok with the mast up. I have done that and it was most successful when we pulled the cable into the top of the mounting location and out through the bottom of the mast. How you route the cable is something you will have to decide but be careful not to bend the wire too tightly. That may damage the coax inside.

Moody Buccaneer · Mar 9, 2006

Thanks Acoustic

Nice to hear a comparison of the same unit in two positions. I was wondering what it would be like to sail off the coast of Maine when I was on the Fast Cat. It was the slop 24 hours after Frances passed by in '04, at night, and foggy. The only word I could come up with for being on a sailboat that night was ... scary ... I'd want the damn radar on the masthead!The Ocean Navigator link made what seemed to be good points. The stability of the antenna is important. A 30 foot boat does not provide a very stable platform in rough conditions.Patrick, what do you think of the current crop of pleasure marine radars? Are the little 2kW units a good value or should 4kW be considered entry level?Is the quality of Raymarine, JRC, and Garmin about the same?Edit:An external, permanent conduit is available from Scanstrut

Maine Sail · Mar 9, 2006

Quality is about the same

JRC makes very sturdy units but the user interface is not user friendly and they are very bare bones. If all you need is radar than it's decent stuff. Most of the lobster guys up here use them because of price. In terms of quality I think Furuno is the most durable but not until you get into the bigger commercial fishing systems. In the 2KW range I chose Raymarine. Feature for feature it has everyone else beat including price. On my old C-30 I had an older Furuno but the Raymarine technology is far ahead of the "small Furuno stuff" at least when I purchased mine in March 05. A 2KW dome should be fine unless your dealing with drug smugglers going 85 knots. The only thing you will loose over a 48 mile radar is seeing storms at a distance. The curvature of the earth prevents you from seeing much more than 25 or 30 miles anyway unless it's a very tall target or a storm cloud in the sky.As for Garmin they are to new to the radar scene for me to judge but I can say that a 2KW dome that's 28" in diameter vs. one that's 18" in diamater has no place on a sailbot under 45 feet and they are very, very pricey.I really like Garmin's plotters and think they are the best hands down for being easy to use, this from a guy who owns a Raymarine C-80, but the Garmin radar has a ways to go to prove itself. A Raymarine C-70 or C-80 plotter with a 2kw dome is a very nice package. Don't get me wrong I really like my C-80 but you actually might need to look a the manual vs. Garmin where you can buy a plotter and throw the manual in the trash becuase you'll never need it.. One thing I really like about my C-80 is that is has a glass screen so you don't scratch it when cleaning salt off of it. I ruined a Garmin screen using the wrong cleaner. My radar is connected in the bilge with two molex connectors I purchased at Radio Shack. They work great but it took me 2 hours to assemble the connectors. Very tedious work! The reason I use them is so I can wrap the entire connection in 3M super 33 electrical tape when I'm finished. You can't do that with a t-strip.. Just count the wires and go to the shack and buy a male and a female connector with that many pins. I don't leave my cable laying in the bilge though. I run it up under the sink to keep the connection out of harms way.I have been purchasing all my electronics from "Droken Leg Dave's Marine Electronics. They guy is great and will always give you a package discount..

patrick · Mar 9, 2006

Garmin GMR 20 or 40 look good to me

but I have NO DIRECT PERSONAL EXPERIENCE. The signal processing is in the scanner and there are apparently no coax and other control cables as most radars have. The fewer connections and smaller cable should make a much easier, simpler, and more flexible installation. There is a reference in the installation to shielding the network cable if it is run near a radio coax but that is probably just boilerplate.I like the fact that the cable looks like it would be much much easier to install than my Raytheon. The Garmin has separate power and network cables. The install instructions call for a 1 1/4 inch hole for the cabling but that sounds way too big to me. I do not know why such a large hole would be required except for the scanner retaining rings.They say not to cut the cable but I wonder if a tech with the right tools might do that ok... A splice would be much simpler, too. I will have to find one of these on display somewhere.The network cable has an rj45 connector so it should be easy to route anywhere and multiple display locations would be much easier than with the Raytheon.The scanner being bigger is a sailboat drawback but conversely the receiver is probably far better due to it having a better antenna. A larger diameter might be less of a physical hangup for the jib since it would theoretically let the sail ease around it better. I do not really know if that is true or not but it sounds plausible. It is still bigger and that is a windage problem.One concern I have is that there are connectors on the bottom of the scanner instead of a weatherproof feedthrough for the cable like the Raytheon. I would worry about moisture getting into the network connector but maybe they have a good solution to that. That would clearly be more of a concern to me on a pole mounted unit since there is a lot more spray at the lower altitude.All things considered and given the fact that I have not installed or used the Garmin, I would go with it if it is as I expect. Installation on the mast would likely be much easier and that is the biggest deciding factor for me.

Moody Buccaneer · Mar 9, 2006

Thank you both

I was watching this thread because I find myself considering Radar for the first time. Sailing time in BC is limited enough without giving up much of Fogust.The strength issue is not a concern for me, I can fab and install a pole unit or arch that I would not worry about.Thanks for clearing up the logic of the height question. On my C30, I think a gimbaled mount that puts the Radar above the gooseneck should provide me with what I want. I want to get some other antennas off the stern rail anyway.I could do a proper mast install also, and that would still be an option if the arch mount does not work out.My view is skewed a bit on this, since I hate mucking with mast mounted Radar as a rigger.IMO the "proper" place for a Radar would be the mizzen on a ketch or yawl, or above the hounds on the foremast of a schooner.

Thanks again for the insights.

Moody Buccaneer · Mar 10, 2006

Um ... Jack one word

Conduit?

Steve2747 · Mar 10, 2006

Patrick...

You're the very reason that some fail to post here. I don't post here yet, as I'm in the learning process and am trying to learn all I can by reading what others are asking. At this point, I'm getting plenty of information for now, I will get to the point of asking questions later. If this causes a response from you stating that I'm not bright enough to be on a boat, then so be it. We all learn by asking questions, or listening to others who ask questions. You stated "If someone is intimidated by my tone to the point that they do not ask an important question, they are certainly not prepared for the sea." You make my point. We are not prepared for the sea. We ask questions so that we may become prepared for the sea. If there is a pompous a** on here who decides to talk down to those of us who aren't as intelligent as you obviously are, then it discourages us from asking questions. Why would you want to discourage someone from asking a legitimate question in order to learn more in order to be "prepared for the sea"? I guess I just don't understand. Think about it. With the proper tone you could impress us all with your superior intelligence. Help me understand.

patrick · Mar 10, 2006

Bill, if someone asks a question,

that is one thing. If someone posts grossly wrong information, I will say so. Sorry you don't like my responses but I spend a lot of time looking for stupid people who get into trouble for some incredibly stupid reasons. As an example, a while back, two of them were found eaten by bears. Most of their bones were recovered minus one skull. I spent ten days sleeping on a couch, eating out of vending machines and missing work helping to find them and it took another three months for someone else to finally locate their remains. They would have lived long and fruitful lives but for one stupid series of mistakes. I am not the only guy who does things like this and I am not looking for any thanks here. I would just like for people to think about what they are doing and if it takes a poke in the ribs from me, ok.If you have any real questions, I will attempt to help you. I would prefer that you leave out the complaining. That belongs in the angst section.

Wiring & Radar Installation on Deck-stepped Masts

George B., s/v Freya

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