Speaking of FOG . . . . . .

[CaptainScott]

With todays question I was thinking about fog and a sailboats visibility so I thought I'd share a few experiences with you. Please note these are non scientific and hold no real value other than my personal experience.


Radar VS Radar reflector.
First a simple concept. Radar allows the operator of the radar to see. The reflector allows you to BE seen. If you have radar, you still need a radar reflector! Most radar operate at different frequencies so . . . If you have radar, and it is turned on that does not mean you can be seen by others. You still need a reflector!!


Now the fun stuff. Reflectors and do they work.
In short, YES!

We have radar on Destiny. I regularly use it on clear days. The idea being I can rationalize what I see on the screen vs what is actually out there. When fog hits I can use the radar and picture what should be out where I can not see.

Things I've noticed. Almost all power boats are readilly visible on radar. Yes there are a few that are hard to see but in general, I can see them clearly. Almost all sailboats can NOT be seen very well on radar. In fact, they look like clutter on the screen and are NOT recognizable as a possible threat.

Add a reflector to a sailboat and suddenly they are very visible! VERY visible! I have however noticed a few things about different reflectors.
The round big ugly ones hung on the aft stay work fantastic. The long skinny ones that folks hang high on the mast looks sleek and cool work too however I have my reservations. We were running head to head with another sailboat in the distance and she was quite visible with my radar. I could not see her reflector until they came close and passed us to port. Then I could clearly see their cool sleek reflector hanging verticle near the top of their mast next to the mast. I thought to myself, Cool! I might have to get one of those and put my current reflector on Lady Jo. Well, until . . . . . as the went behind us the boat litterally disappear on my radar! As she made distance between us I flat lost her completely on radar yet she was clearly visible to me! WOW!

So . . . . my thoughts are two fold. One, maybe their mast prevented the reflector from working since it was mounted to the mast and completely shadowed by the mast from my view after they passed? The other thought that came to mind is why did they not hang it off the aft stay where the other reflectors are? Is the fancy reflector that sensitive to mounting angle? I don't know.

Either way, the cheap simple round shaped reflector that is seen on Destiny below most certainly works and I see no need to spend 3 times the money for a cool reflector that in my experience did not seem to work as well as the cheapo! ( cheap is relative of course )


Just thought I'd toss my two bits at you all!
Scott



See the round thing on the aft stay about 25% the way up? That is the reflector.

[Alanhod]

[Mario G]

Great subject Scott and now that fall is upon us and I know the fog will be coming Shaken Knot Stirred's next addition will be one of those funny looking round balls. Not sure if we will be getting a radar system fir it anytime soon but then I don't see a need for it when I will not sail thru fog on the coast.

[trev]

I agree, great subject. I'll be sailing on Lake Superior next year. It can go from 80 and sunny to completely fogged in in minutes at anytime. I'm not sure a radar will be in the budget but I will have a reflector similar to yours for sure.

[NYCSAILOR]

I sail in foggy , busy shipping lanes... so I snagged a raymarine 18" 2kw radome and c80rc display....

So.... I have two immediate questions...
1) where to mount the radome...
I thought a dedicated stern mounted pole/mast OR
a mount onthe backstay...
The boat yard insisted that it should go up on the mast for better performance and health ( it seems the radar beams emitting over the cockpit is not very healthy for the crew) I was worried that the deckstepped mast might not want radar dome up there but he said it was plenty strong...
he said it would NOT affect or complicate stepping/demasting at all and I was also worried about tacking the genny...

2) powering that sucker... I have only one battery but a solar panel and the alternator fromthe OB.. I think I will need another house battery at minimum...

[CaptainScott]

Yes, where the radar is mounted is important.
The transmitter will transmit on a plane. Picture a round flat dinner plate.
That would be how the signal is transmitted! You DO NOT want to transmit through people. The radar should be higher than the normal seated area in your boat. Also remember that transmition plane. IF you heal heavily it will affect how the radar works if the radar can not pivot.


So, consider WHERE you will use the radar. IF you sail off shore and are concerned about large ships then the higher the better for sure! Also the larger seas for off shore sailing would benifit. Up the mast is FANTASTIC! However, if you are in close quarter, smaller seas, lots of smaller traffic then a lower mounting arangement might be better. Remember how it transmits on a place. If there is a smaller skiff your radar may transmit right over it. Or better yet, if you are looking for that bouy or marker in the fog . . . . a lower mounted radar will be a bit better.

All that said and since most of us do not sail to far off shore in bad conditions I would look more at the costs of mounting the transmitter up the mast or on a pole.

My radar is rated at 16 miles however I normally use it at 1.5 mile range and regularly step down to 3/4 mile range! I do use the higher abilty about once every few years. Crossing Haro Straights can get exciting with multiple shipping lanes and MANY ships in the fog so I use higher power settings there. You might note our radar is mounted on on the . . . .RADAR arch on our stern and it works perfectly for our closer in sailing needs! You can see it in th ephoto above. It is behind and just above the bimini top. The GPS antenna is the tiny white dome that appears above the radar transmitter. A radar pole would have accomplished the exact same. We do not have a pivoting radar mount. Why? generally when it is foggy here there is zero wind so we are not sailing in fog. So we are perminantly fixed.

As far as power usage? We have an abundance of DC amperage so we are fine. Also as mentioned we usually are motoring in the fog so radar is not a power concern. If I had only one battery I'd most certainly add a second or house one for many reasons beyond just radar!

Hope this helps!

Scott

[tgentry]

Scott,
I was looking at those new fangled reflectors at the boat show. The guy I talked to recommended zip tying to the shrouds. Maybe that was due to the mast shadowing that you observed.

I have the same kind you have, it came with the boat, but so far I just have it ready to hoist if needed.

[EmergencyExit]

I think a lot of guys sail in a fog a lot of the time.

Present company excepted, of course..

[Paul]

Mario!!! "Now that fall is upon us"!!! Bite your tongue - I haven't gotten my boat in the water yet! Man, I got to get moving. Let's see, this weekend; father's day and the kids want to spend it with me. Next weekend; taking care of the grandchild solo. The weekend after that; a wedding to perform. Man summer is zoooomin' by!

[NYCSAILOR]

Scott,

what a informative -to the point- response, as always thank you... I have a RL80 CRT display and the think is kinda big.. so I am trying to figure out where to put the display in a way that would be useful to the helm/// maybe mounted in a "hatchboard" that would slip in/out of the companionway.. but that would block the companionway and might be a safety issue there... I also think if I go through all the trouble maybe suck it up and save up for a LCD /chartoverlay display but then that is worth more than the boat! and not something I would use more than once or twice... maybe rethink and go AIS but that pricey and limited..