I fitted a Mini Tri-lens radar reflector to the top rail of my motor boat. The recent MAIB report concluded that the tri-lens was the best passive reflector but that only the Maxi size had an adequate RCS (radar cross section), The Maxi is large and heavy at about 12lbs, compared with 2lbs for the Mini.
My thought - like radio telescope arrays, how would two Mini reflectors a couple of feet apart compare with one larger reflector? The weight would still be only one-third of the Maxi.
The MAIB report was very worrying! Bearing in mind that all the cylindrical types only apparently work at peak efficiency when vertical, there seems to be something to be said for having two, attached to shrouds on sailing yachts, so that one is vertical whichever tack you are on, but weight aloft is an issue, too. I'm afraid I don't know if two is better than one in other respects, but it's a very interesting thought!
I fully agree with Cathy about the worryingly poor performance of yacht radar relflectors. However two is definitely not better than one, in fact two is positively dangerous, there was a report in either PBO or YM a couple of years ago, with a lot of input by the military testing organisation and two were found not to show up at all. Curiously the best radar reflector was a yacht's engine! They found that a bin bag stuffed full of crushed up kitchen foil outperformed every commercial radar reflector.
The subject of radar reflectors is full of pros and cons. We very nearly ran down a yacht sailing in a good force four and they were sailing close to the wind and therefore well healed over. We are a motor cruiser and had slowed to about 5kts, were sounding our fog horn and had posted an alert lookout up on the fly bridge. The yacht did not show on our radar, until, after the event, I reduced the rage to .75n.ml., so it was the quick and decisive action of the lookout, who took over the controls of the boat and made a substantial alteration of course, thus saving the day.
Lesson learned: Reduce the range on the radar to the lowest practical range, and post a dedicated lookout with clear instructios of what action to take in certain situations, and never rely on your radar reflector or your radar.
In very poor viz' post a look-out. If you'r not well equipped and you'r in port....stay there.
Get on CH 16 to ask CG about shipping in area, and to give your position to others. Perhaps put vhf on scan to pick up local shipping on other frequencies.
Give blasts on a horn as per regs. Shipping often do not have lookouts up front to listen for others so it's up to you to keep out of their way.
Ideally use radar and AIS and if you have a plotter and/or GPS check your position often.
This is where an AIS transponder is handy and an active radar reflector.
If sailing, have your motor running for possibly quicker response and if in very light winds consider getting sails down and just motoring. (Engine noise can be a problem here when you are listening for others.)
I only wish time was on my side this winter when the mast was down, as the extra cost of fitting these gismos could pale into insignificance when you consider what disasters may strike.
If in shipping areas it makes sense to get into shallow water, over sandbanks or close inshore, Fog in this country rarely lasts for more than an hour or two!
Other things to do - Get the liferaft on deck and ready for deployment, insist all the crew are wearing lifejackets and harnesses plus insist that everyone is well clipped on. Even if hit by a ship it almost unheard of for the yacht to go down immediately, but what often happens is a glancing blow with the yacht bashing along the side of the ship, if not clipped on you are very likely to be lost over the side!
It pays to have some standing in the eyes of the bows as a look-out, listen-out, they get a better view higher up and one's own engine noise is less intrusive.
It could make even more sense to hoist someone up the mast, the visibility at height is considerably further as fog typically only lies thickly at just above sea level.
Putting on your Mast-head lights and Nav lights as per Collision Rules is important too!
---"If sailing, have your motor running for possibly quicker response and if in very light winds consider getting sails down and just motoring. (Engine noise can be a problem here when you are listening for others.)"---
I think all of the points here are excellent but this one of Scotties is probably the best of all, if you are motoring; you'll be upright and probably give a better radar reflection, your enging running will firstly give others a better chance of hearing you and secondly, it will allow you to stop very quickly.
