Questions about Radar on smaller boats?

Jul 27, 2011
5,002
Bavaria 38E Alamitos Bay
My radar display is below and it is usually turned off, or is on standby. So, it is not central for piloting me boat. I use the Fujinons far more often than I consult the radar display. But when I feel I need it, I’m happy that it is there.:)
 
Jul 27, 2011
5,002
Bavaria 38E Alamitos Bay
One FYI note about stern posts versus masts for mounting radar. Stern posts are usually off-set to starboard or port, whereas the mast is on the centerline of the vessel. Thus, for radar mounted on stern posts the target bearing of a mark may not agree with your GPS (or chart) bearing of that mark. The discrepancy grows as one approaches the mark. In total fog of near zero visibility this can be a bit disconcerting if not down-right confusing the first time you encounter it.:doh: Obviously, it is more cautious with close encounters to stand clear of the radar target even if the GPS is telling you that you are already on course to avoid it, etc. That is, GPS may be telling you that you’ll pass the mark on your port when the port-side radar is telling you it’s dead ahead. It’s dead ahead of your radar (line-of-sight), but not your bow. Yes, it’s a small but noticeable discrepancy. In super dense fog when you are totally dependent on instruments, even these small things can alarm you.:yikes:
 
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Likes: rgranger
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
If it were me I'd do a temporary setup on the stern quarter. Messing around in fog is un-nerving and radar is basically a necessity, HOWEVER, one doesn't do it that often, at least in most places. San Francisco Bay Area (especially the Sunset District of SF), New England (Block Island to Point Judith), even Puget Sound, but then there are typical times of the year when that happens. Around here its in the month of Fogust.

For the few times one really needs radar, with that simplified unit (only needing power and there is no other cable needed), a setup with a removable pole and removable radar unit that can be stowed below would work on your boat. The boat probably has a pushpit (Disclaimer: not every install detail is spelled out) so rigging up a pole attach setup with a couple quick -release latches, wing nuts for the radar, and a power receptacle would keep the boat lines looking clean. Also, when you go to sell her (don't know if I should say we sell our women) you can keep the radar.

That would be my suggestion but then different fog for different places and "different strokes for different folks".
 
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Likes: rgranger

TomY

Alden Forum Moderator
Jun 22, 2004
2,759
Alden 38' Challenger yawl Rockport Harbor
I ran across this ad yesterday for the wireless Furuno radar that displays on any iOS device.


As a coastal cruiser, I use my cell phone for a lot of my navigational needs. I have Navonics on my phone and I also have the NOAA radar app for watching storm cells. This Furuno model can display right to a phone or tablet and active radar would be nice at times.

This ad got me thinking, why do you almost never see a radar dome on the smaller pocket cruisers. I do a lot of coastal cruising (plan to do a lot more in the near future) and I have been caught out in fog. I would have loved to have had radar in those conditions.

So here are two basic questions.
1) Why don't you see more RADAR on smaller cruising boats
- Does the dome add to much weight aloft? (you could put it on a pole on the stern)
- Do they draw too much power ( I think I know the answer to this already [ ~25W])
- Other reasons?
and...
Good question and true what you say. I've been sailing the coast of Maine for 30 seasons and still don't feel the need for radar. There have been a few times when I wished I had it but too few get me interested.

Your reasons are on: The dome would add a lot of weight to our smaller mizzen that we step and un-step, easily, by hand. Plus moving it, storing it, maintaining it.

Radar draws too much power for us. We have very low DC power needs and hence, charging, and want to keep it that way.

And cost. We spend our money on sails and maintenance. With that covered, I'm happy with the boat.

Other reasons? We don't night sail much and motor at night, even less. A surprise to many, we don't get that much fog here in Penobscot Bay. Once or twice a year, we'll get a thick fog, and usually just wait until it clears. Fog is also something that was much more of an issue when we first started coastal sailing.

These days, I like sailing in the fog. I think it's safer to sail than motor. Slow, quiet, and we avoid major traffic lanes, it's fun.
 
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Likes: jon hansen
Apr 8, 2011
768
Hunter 40 Deale, MD
Generally I agree with the sentiment that you don't NEED radar to sail/motor at night, and not even in heavy fog. Watermen safely navigated for centuries without it...though not without incident. I spent many nights in the Marine Corps in armored amphibious vehicles navigating the New River near Jacksonville, NC with fishing and pleasure vessels around - and we had NO navigation lights, no radar, no foghorn, no chartplotter, and a max speed of 8 kts. We had a white spotlight we'd turn on if boats got close, and we'd spotlight ourselves as a last resort so they could then see us, but we were training to have NOTHING on at night for stealth and navigate by map, night vision goggles, and compass. I don't think we even had VHF radios that we could tune to marine channels, so we couldn't communicate that way either. We were...mostly...successful (no boating accidents but we MAY have landed at the wrong spot a time or two). I've made sailing trips from Bermuda to NY and NY to Maine as crew without a radar display in the cockpit. Setting an alert watch, using other tools such as AIS, a fog horn and chartplotter will add a prudent safety margin. And for most of us the number of times we're out in really heavy fog is pretty small - if my experience is any indicator. BUT, sometimes it happens, and you may not have a choice to be out in it - you may already be there. On the Chesapeake Bay I've only seen heavy fog a few times, but when it has happened the visibility was not even 1-2 boat lengths. The fog settled in unexpectedly overnight once, so I navigated out of an anchorage without radar at a crawl, and it seemed like it took forever. Boats appeared VERY close aboard when I came across them. Another time, again without radar, I declined to enter a fog bank outside the West River, hearing speedboats and having no idea where they were, or which direction they were travelling - there's too many idiots on the water for me to feel they were keeping a good watch, motoring at a safe speed, and listening for foghorns. With radar I would've felt much safer entering that wall of impenetrable fog.

This is all part of what makes sailing so interesting - and preparation so important.
 
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Jul 27, 2011
5,002
Bavaria 38E Alamitos Bay
And this is like how they might have done it throughout those centuries. Dana‘s narrative on returning to Boston after departing San Diego months earlier with a boat load of hides.


“The soundings on the American coast are so regular that a navigator knows as well where he has made land, by the soundings, as he would by seeing the land. Black mud is the soundings of Block Island. As you go toward Nantucket, it changes to dark sand; then sand and white shells; and on George’s Bank white sand; and so on.“ ... “... Block Island bore, by calculation, NW1/4W fifteen miles; but the fog was so thick all day we could see nothing.” ...“Toward night a moderate breeze sprang up; the fog however continuing as thick as before; and we kept on to the eastward.” ... “The fog continued through the night, with a very light breeze, before which we ran to the eastward, literally feeling our way along. The lead was heaved every two hours and the gradual change from black mud to sand, showed that we were approaching Nantucket South Shoals. On Monday morning, the increased depth and deep blue color of the water, and the mixture of shells and white sand we brought up, upon sounding, showed that we were in the Channel, and nearing George’s; accordingly, the ship’s head was put directly northward, and we stood on, with perfect confidence in the soundings...” “...at eight o’clock a small fishing schooner, which we passed, told us we were nearly abreast of Chatham lights.” “... and at four o’clock, thinking ourselves to the northward of Race Point, we hauled up on the wind and stood into the bay, north-north-west, for Boston lights, and commencing firing guns for a pilot.”

R.H. Dana, Two Years Before the Mast:)
 
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Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
Very interesting post about what Dana wrote in "Two Years Before the Mast".
Locally (well sort of), on the West coast of Vancouver Island, for many years, a ship made regular stops along that cost to deliver and take on supplies, mail, and passengers. The coast is littered with all kinds of rocks and it is very ragged and the weather is, frankly, often very nasty ... and foggy. What they used to determine location was an air horn, in conjunction with the compass and the ships log. Given the tidal currents and eddies, navigation via time and distance, and using a compass, is a real challenge. With the air horn they'd blast it in the direction of the shore then count the seconds for the return echo. Based on how long it took for the echo to return they would calculate how far they were from shore.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
There is also a "dead zone" around the boat which gets larger as the transmitter gets higher off the water.
...mount it as high above the water as feasible on your boat
My experience, and practice, has been that when I need radar I need it for things that are close to the boat, like navigational buoys and boats I might hit. I lowered the radar on the mast to reduce the dead zone. The calculation I employed was to make the minimum range of the radar coincide with the vertical beam width touching the water. With that I could see buoys as close as technically possible with that radar. I didn't care much about things that were far away.