Radar or No?

[Wyb2]

For those that sail in areas where fog is an issue, what are your thoughts on having (or not having) radar? We had radar for most of the year that we spent on the big boat, and it was a great tool, but we only encountered fog briefly one time. We are looking to start taking the 25 out in Maine sometime in the next couple years, and my understanding is fog is a somewhat regular thing up there.

In my mind, having radar seems pretty invaluable if you are trying to get back to the launch and dense fog rolls in. On the other hand, I’d be surprised if every little trailer sailer in the area had radar. Is there something I’m missing?

The cost is one thing, but also if I want to keep it off the mast (which I think I do), I would probably have to install an arch or a pole that I wouldn’t otherwise need. Then, if this pole or arch is tall enough to be above head height for sailing, does it need to lowered for trailering?

[Russ]

I've only used radar a couple of times on a friend's boat.
I have used a chartplotter and love it. At night I can navigate to anywhere with the chartplotter. Back to the exact spot where I anchored in pitch darkness.

I imagine radar is especially useful in fog to avoid collision with other vessels. I can't imagine using it to navigate into port.

[Wyb2]

Oh yeah, definitely going to have a chart plotter for general navigation. And agree, radar is mostly about seeing other vessels in poor visibility.

99% of fixed obstacles will be marked on the plotter, it’s the moving ones I’m worried about. If we are sailing in and out of the Portland area, there will be tankers and container ships and about a bazillion lobster boats moving about regardless of fog.

[Be Free]

All US charts have a zone of confidence rating. Close to shore you are more likely to find an A1 or A2 but you don't have to get far offshore to find B or worse.

A1 +/- 16.4' and your depth +/- 1.6' + 1%
A2 +/- 65.6' and your depth 3.3' + 2%
B +/1 164' and your depth 3.3' + 2%
C +/- 1640' and your depth 6.6' + 2%
D is listed as "worse than C"
U Unassessed

Your GPS is accurate to somewhere between 10' and 25' most of the time so you need to take that into account as well.

Your chart plotter tells you where things are believed to be based on the charts it is using and where it thinks you are based on the GPS position it is receiving. Best case you are probably within 10' of where you think you are and the object on the chart is within 16' of where the chart says it is. It is important to understand the limits of your instruments and not try to get more information out of your instruments than is actually there. Close to shore, everything (including you) is probably within a boat-length or two of reality.

Radar shows you where you are in relation to where things actually are even if they are moving and/or not on the chart. It won't tell you where you are but it will tell you are in relation to another object. Radar range accuracy is usually 1% of the scale or 30 meters, whichever is greater. Call it four boat lengths.

You are not going to want to use either one to parallel park.

One item you did not mention is AIS. You can get a transceiver for much less than radar, it is much easier to install, and it will show you the position of the tankers for sure and the lobster boats assuming they have not turned theirs off to protect a secret spot. You will be transmitting your position and the fact that you are a sailboat as well. That puts the majority of the big moving objects on your screen within the accuracy of two GPS receivers. Call it two boat lengths.

In heavy fog your chart plotter is going to tell give you a good idea of where you are and where some of the "hard bits" around the edges are supposed to be that you probably want to avoid. Radar and AIS may find some moveable "hard bits" that you may also want to avoid. Of course, you have also slowed to a safe speed or stopped and you are sounding your fog horn at the appropriate rate (right?).

In the end though, it's your eyeballs looking around you that are going to have to be the instrument that separates the "should be" from the "what is". If they can't then you are going too fast.

[rsvpasap]

I've used radar on my 2002 26X in the Great Lakes and the PNW. The radar and mount combined weigh only about 20 lbs and have no impact on boat stability or handling under sail. I installed it about 7 ft above deck height so I could put it in place after raising the mast, though in practice, my boat lives in the water constantly. I found it to be most useful with providing a second set of eyes at night in the rain. But then it would be best to not be underway at night in the rain, regardless of whether you have radar. There's a lot of stuff floating around out there.

[Wyb2]

All US charts have a zone of confidence rating. Close to shore you are more likely to find an A1 or A2 but you don't have to get far offshore to find B or worse.

A1 +/- 16.4' and your depth +/- 1.6' + 1%
A2 +/- 65.6' and your depth 3.3' + 2%
B +/1 164' and your depth 3.3' + 2%
C +/- 1640' and your depth 6.6' + 2%
D is listed as "worse than C"
U Unassessed

Your GPS is accurate to somewhere between 10' and 25' most of the time so you need to take that into account as well.

Your chart plotter tells you where things are believed to be based on the charts it is using and where it thinks you are based on the GPS position it is receiving. Best case you are probably within 10' of where you think you are and the object on the chart is within 16' of where the chart says it is. It is important to understand the limits of your instruments and not try to get more information out of your instruments than is actually there. Close to shore, everything (including you) is probably within a boat-length or two of reality.

Radar shows you where you are in relation to where things actually are even if they are moving and/or not on the chart. It won't tell you where you are but it will tell you are in relation to another object. Radar range accuracy is usually 1% of the scale or 30 meters, whichever is greater. Call it four boat lengths.

You are not going to want to use either one to parallel park.

One item you did not mention is AIS. You can get a transceiver for much less than radar, it is much easier to install, and it will show you the position of the tankers for sure and the lobster boats assuming they have not turned theirs off to protect a secret spot. You will be transmitting your position and the fact that you are a sailboat as well. That puts the majority of the big moving objects on your screen within the accuracy of two GPS receivers. Call it two boat lengths.

In heavy fog your chart plotter is going to tell give you a good idea of where you are and where some of the "hard bits" around the edges are supposed to be that you probably want to avoid. Radar and AIS may find some moveable "hard bits" that you may also want to avoid. Of course, you have also slowed to a safe speed or stopped and you are sounding your fog horn at the appropriate rate (right?).

In the end though, it's your eyeballs looking around you that are going to have to be the instrument that separates the "should be" from the "what is". If they can't then you are going too fast.

I did forget to mention AIS. I probably will get that as it looks like you can pick up a class B transponder for ~$600 and install is pretty straightforward. On the big boat we had an AIS receiver and found it very useful, I don’t remember if the transponders were more expensive at the time or I was just being cheap.

The idea about going slow and sounding the fog horn is kind of where I’m mentally stuck. I know this is technically an acceptable way to deal with fog, but I just can’t picture how it’s sufficient in practice. I can do it, but I kinda doubt the lobster boats are going to drop down to 1 knt when time=money. And they are probably running a dry exhaust with a rusted out muffler, there’s no way they are going to hear any horn I have until we are already on top of each other. I’m not sure how prevalent AIS is for lobster/fishing vessels in the area, but I think there are plenty that are under the 65 ft that would require it. So in my mind I’m really just relying on them seeing me on their radar while I sit like a duck. But maybe my assumptions are wrong, and it’s not as risky as I’m picturing.

I guess maybe the question I’m really asking is if someone here does have experience dealing with fog without radar, and if it’s as dice-rolly as I’m imagining it?

I've used radar on my 2002 26X in the Great Lakes and the PNW. The radar and mount combined weigh only about 20 lbs and have no impact on boat stability or handling under sail. I installed it about 7 ft above deck height so I could put it in place after raising the mast, though in practice, my boat lives in the water constantly. My candid opinion is that there are much better ways to spend $2,000 on your Macgregor. On those days when you're genuinely dependent upon radar, you really really should not be underway. Radar picks up other boats, but it doesn't help much with floating debris. I found it to be most useful with providing a second set of eyes at night in the rain. But then it would be best to not be underway at night in the rain, regardless of whether you have radar. There's a lot of stuff floating around out there.

I agree with simply avoiding poor conditions as much as possible, but the one and only time I have run into fog it showed up in the middle of an otherwise perfect day. Luckily it moved on after 20 min or so. I also agree that radar seems like a lot of expense and complexity that may not get used that often. But the fog issue is the one thing stopping me from saying “nah, I don’t need that.”

[Be Free]

Wyb2,
The cost of AIS transceivers has dropped quite a bit in the last few years (with a slight inflation/supply chain bump a year or so ago). In my opinion, it's gotten to the point where there is not enough difference in the price of a receiver vs. a transceiver to justify a new receive-only install.

I can't speak to the behavior of lobster boats or even of how boats change their behavior in the fog from personal observation. We don't have lobster boats here but we do have a fair number of crab boats. Around here I've found that the professionals act like professionals and the main danger is from the weekenders trying to squeeze too much fishing into to little time. Fog, when we get it, is usually gone by late morning and has never posed a navigation issue for me.

I just try to follow the rules and expect professionals and most of the locals to do the same. I expect the tourists have no idea what they are doing and probably wouldn't do what they should do even if they did know. They are simply a moveable hazard that has to be dealt with a safely as possible. I'm only joking a bit when I say that I've long suspected that when folks rent boats (particularly pontoon boats) they are required to leave their brain as part of the deposit.

Bill

[Highlander]

Hi all my radar will pick up a bouy or another object like a tire 10-12ft within my boat , my GPS shows me about about 4-5ft off my port side , I believe my AIS is approx within my boat length if properly calculated during set up












J

[Highlander]

More pics















these give u an idea of what can b done

J