Radar Mast ideas?

[tabaka]

I've gotten caught in enough fog this year that I finally cracked open the purse strings to buy a radar...I was curious if anyone else here had built or installed Radar masts or arches on their boats and where or how you did it?I have a Mac 19 powersailer but I imagine the placement would be similar to that on a 26x/m It's just that the boom doesn't end so far back on the bigger boats.If anyone has any ideas about it or better yet pictures of completed projects I'd appreciate it.It's a Raymarine SL70RC with an 18 inch dome that I bought.

 

[70623]

Did you get a generator too

Radar consumes a great deal of power. I have one similar to what you got on my power boat. Eats too much power for practicle use even on my Bristol 30 with 8 large golf cart batteries on board. Remember they eat at least 10 amps continously. That's as much as leaving your car lights on, on high. It's not the displays that eat the power, but the antenna. It is sending a powerful radio signal out and reading the signals bounced back. They do eat less than they used to, but on a 19' boat, where are you going to carry all the batteries? The usual mounting is either off the mast (on larger sailboats) or on smaller sailboats (under 36') off the back stay. The backstay mounts are gimbled (as radar won't work when you heel more than 3-4 degrees) to keep the unit (dome) level. Some domes will give you a little range (1/16 mi.) at a 4-5 degree angle. Providing you don't have to turn up the clutter gain (which is exactly what you do in a fog). Range will be dependant on height more than power on such a small boat. To get the most out of your unit you need it mounted about 18' up and level. Good luck.

 

[MrBill_FLL]

hmmm, practical sailor had a shoot out on radars

some of the smaller ones used about 5amps IIRC...let me take a look and see which ones used least amps..

 

[70623]

19' boat & RADAR

Watch out how they rate these. The wattage consumption adds up fast. X number of watts for the display + Y number of watts for the antenna + Z number of watts for the antenna motor. I've never seen one anywgere near 5 watts total. AND without all the parts working, the RADAR isn't working. Old CRT screens used 15 amps 12 volts alone. A 6 Watt antenna can use 5 amps just for the antenna motor, then if it was 100% efficient it needs another .5 amps for the signal. The displays have gotten much more efficient as they are no longer CRT but instead use LCD. This brings there power consumption down to about the same as a fish finder display. But a fish finder only pulses its sonar, a RADAR sends it's signal all the time. And has to recieve that singnal and amplify it too. Only the smallest units stand a chance of being used with out the motor running to keep the batteries charged, and then only for short periods of time. The new color Radar units integrated with a Chart plotter tied into a GPS are best if you aren't going to look at it an awful lot so that interprtation is both accurate and useful. It can be hard to tell what you are looking at, and easy to miss things that you need to see on an LCD display (gray scale). It takes time watching these to understand what you are seeing. And on a sail boat, with limited power, you won't get enough time to really know your unit. Add to that and that a sail boat heels, this changes how everything looks on the RADAR too. Don't get me wrong, RADAR is great, I have one on my power boat. BUT on a very small sailboat, there are so many other, cheaper things that are so much more useful, it just isn't at the top of the items I would add to the boat.

 

[tabaka]

not for full time use

I don't plan on running the thing all the time. Just to save my butt. When it's foggy I keep the sails down and run the engine to get myself into a safe port or anchorage. Heel angle shouldn't be too big a problem and the engine is putting out roughly 130 watts from the alternator (a bigger one is available I think). That should offset the drain long enough for me to get into safety. Full power this thing uses 35 watts.The engine starts easy with a rope too in case I do run the batteries down.I've got some pretty tricky bars to cross over here and I'd prefer to see Jetty rocks on a screen rather than 10 feet off my bow and closing.(edited to correct alternator output)

 

[MrBill_FLL]

you already have GPS, right?

sorry, I haven't found the practical sailor issue yet, but think 70623 is right, they split the display and antenna amps.... I think (guess) it was the Garmin unit that was abotu 3.5 amps (for radar or display, can't remember which).Its probably in 8-10amp range for both.its a shame you'll have to put that much weight up that high... sure will hurt the heeling.if you can manage a radar arch, w/ solar cells thats what I'd do...if you have a GPS (map) you can tell where the rocks are... radar is for boats/ships right? (and a backup to the chartplotter)

 

[Alex]

Radar on a M19

You may be one of the very few if not the first to put a radar on a M19.Where are you going to mount the dispay?

 

[tabaka]

display mount

I fabricated a dash board of sorts that is u bolted to the safety rail on the right rear of the cockpit. I took a quarter inch plate of aluminum and cut it down to the size I wanted. I ran all the electrical connections down through the same port that the engine wires go through in the rear bulk head of the cockpit.I've got a hummingbird matrix depth finder with GPS and a compass on it so far and there is room there for the Radar display.I don't like relying on the GPS map to know where the rocks are... They just aren't as acurate as an active response from a radar. I often go out through Nehalem bay on the Oregon coast and the bar between the jettys is far too narrow for comfort in the fog.I think the dome only weighs 10 pounds at the most so I shouldn't have too much trouble with placing weight higher up. I'll probably build the mast out of aluminum pipe. Or if I decide I like the solar panel idea, I'll build an actual arch.One of my other projects to work on this winter is a Sea mount for the outboard. I need to move it back about 8-10 inches (maybe more) so I can actually steer with it. The tiller steered 40's that sold with the Mac 19's can only turn about 3 inches to starboard and an inch and a half to port so you end up pinning the outboard in place and steering with the tiller controlled rudders. It makes dock navigation a royal pain at best since you have no steerage unless you are moving.

 

[Robspan]

GPS Track

I can certainly understand being cautious using a chart projected on a gps to navigate through rocks in a fog. If your gps can save tracks, you might try this. Turn on the tracks feature, navigate through the rocks in good visibility, then save that track as a route.

 

[Chris & Lenore - Mac 26S - Teliki]

You need to think in terms of "system"

I understand the requirement of being able to safely navigate in "blind" situations. Consider stepping back from the view of single disparate solutions.GPS does not see ships, radar does not see shoals or low penetration obstructions and maps are useless without knowing your exact position.I am also assuming that a moderate expense can be occurred (the low power consumption radar units are not inexpensive).Anyway, consider a system that integrates electronic charts, GPS and radar. There are solutions which are not priced in the stratosphere - typically chart-plotters which accept radar input on a standard bus directly from the antenna unit (you don't then buy the manufacturers display).This puts the radar information "in context" with your current position and relates it to the map. If you don't trust (or have not verified) the electronic chart accuracy, then simply save several "safe tracks" plus add obstructions as way points as you sail - gradually building up your map with factual data.The main benefit of an integrated solution is that it brings together information in such a way that it is quickly and easily understood in the context of the decisions you need to base upon it. This is the key to any information based decision support process - which sailing in the fog definitely qualifies.Personally, I think it's overkill - but that takes into account my "risk tolerance" as well as other steps I take to avoid dangerous situations. And I'll probably change my view the day I lose a jousting contest with a freighter on a foggy day...Chris