Small Boat Radar

L

Lodds

Well-Known Member
Joined
3 Oct 2012
Messages
92
Location
Home: Heathrow area. Boat: Emsworth Marina
Visit site
Not sure if this question has been asked before.

I have a Centaur and am considering installing a Radar. My motivation behind this thought process is that I am shortly retiring and what to make extended journeys and don't want to be limited by night or fog.
I already have a Garmin 4010 plotter and my VHF receives AIS ((apparently)I have yet to make the connections) My questions to you guys is.

Would it be overkill to have a radar fitted on a 26' boat?
What size 18" or 24" (I would like a 24" radome but I am beginning to think that it would be a huge lump on the mast)?
Would 18" (5% horizontal beam) give me the separation i need?

Power of course will always be an issue for me as I love my electronics, but I think I have for the most part got this covered.

Appreciate as always your comments.

Tony
 
It's your boat and your choice. And your comfort level. A new multi function color radar will be quite a big proportion of the value of a Centaur. There was a long thread a just recently about AIS. Try hooking up the AIS first.

I have a RADAR on my boat. I find I never use it. Partly because it is by the chart table. Partly because I just have not gone sailing when visibility is really bad. Although I never use it. I do like having the option. I don't have a plotter or AIS yet.
If I do sail when visibility is poor. AIS would give me plenty of warning about big boats. and I would see small boats in time. Unless its really thick fog.
Mine is a small monochrome LED Furuno. you can still get a similar model.
You might be able to find a second hand one as the enthusiasts upgrade to combo's
 
Last edited:
In the days when I owned a Vancouver 27 I installed a Raymarine might have been Ratheon RL70 monochrome radar they had just come out! Shortly after installing I was comming back from Camaret and was a few miles out from Fowey in the early hours of the morning having decided to spend a few days visiting friends when it seemed that there was a massive power cut on the Cornish coast, all the lights went out! I pressed on and about an hour later ran into thick and thickening fog. Radar on and I worked my way towards the seemingly narrow Fowey entrance as I got closer continually adjusted the range until I was passing through the entrance with fog shrouding either side. I picked my way up towards Post Pill and found it empty the radar again helping which was below decks but visible from the tiller. From that moment on I became and remained convinced that Radar was an enormous and very useful aid to small boat navigation and as models and boats changed still it remained.
In answer to the OP the 18" will be perfectly satisfactory if you can find a place to mount it on a Centaur.
 
I can't fit radar on my boat but if there was room up there for a scanner I would choose the recently introduced frequency modulated type, which looks better for yacht use, with very low power consumption and sharper images at short range.
One disadvantage, it won't paint things like racons.
 
Resolution is not very important for the kind of use it will get on most yachts. Although it would be nice to see fine detail, the presence or absence of a target is all that we generally need when using a radar for collision avoidance. Two ships can almost always be distinguished by being at different ranges and bearings taken from the centre of a return are generally good enough. The return can be made smaller by reducing the gain, if necessary. For an accurate bearing, AIS will be a better choice.

Radar can be very useful if your sailing requires it, since it can make it feasible to set out when there is an uncertain possibility of poor visibility, where otherwise one might feel compelled to stay in harbour. It doesn't justify reckless navigation, but once every couple of years or so can justify its cost.
 
Lodds said:
What size dome was it?
Click to expand...

Can't remember size, it was 20 years ago. It was smallest they did and that plus a Firdell Blipper made a noticeable difference to roll and windage.

Thinking back, I may have posted the wrong model number, could have been the 1623. We now have the larger 1712 on a bigger boat.
 
Last edited:
Lodds said:
Would it be overkill to have a radar fitted on a 26' boat?
What size 18" or 24" (I would like a 24" radome but I am beginning to think that it would be a huge lump on the mast)?
Would 18" (5% horizontal beam) give me the separation i need?
Click to expand...

Certainly not overkill, but a 24" radome would look wrong! An 18" radome would work fine. You may find it would look better on a pole at the stern than on the mast.

A Garmin GMR18 HD radome will just plug in to your plotter and will simply plug & play. You'd be able to overlay the radar image on the chart, which I find a very useful feature. It's widely available at £1050 or less, inc 15m of cable.

Note that some retailers may offer the non-HD radome for less, eg £850 at http://www.outdoorgb.com/p/garmin_gmr_18_network_radar/ I think the spec is essentially the same, but a call to Garmin's helpful support people would clarify that.
 
Sandy said:
I have AIS and RADAR onboard - I find I use AIS more.
Click to expand...

+1 bigtime. With AIS on the chartplotter you have a lot of easily assimilated info. And with an AIS transmitter you can be more certain that big ships cannot avoid seeing little old you.
 
Definitely fit AIS before spending on radar. AIS is useful in all visibilities and hence used much more often. Also quite fun looking up details of interesting vessels that pass.
If have money left after that - and particularly if sailing waters that are prone to fog and other vessels - then can add radar.

In thick conditions, it is mainly an aid to spot any smaller vessels not broadcasting on AIS - such as many fishing boats and yachts. More fishing boats transmit AIS but man.y do not. In 10 years time radar may be much less valuable (like a sextant)
 
Uricanejack said:
If I do sail when visibility is poor. AIS would give me plenty of warning about big boats. and I would see small boats in time. Unless its really thick fog.
Click to expand...

Sometimes it's really thick fog :)

Last summer we had a day when we were in the approaches to St Malo and at times it felt like we could barely see the bow from the cockpit. Radar absolutely essential, and some of the returns passing by us sounded like small outboard-powered boats, RIBs or maybe the smallish GRP boats with wheelhouses that the French are fond of. They were traveling moderately fast and there's absolutely no way we'd have seen one before they hit us. Hopefully they too were using radar rather than just blindly driving into the murk, but as soon as we heard the first one it would have been very worrying to know that there were probably others and not be able to track them ourselves.

I imagine few people now do the sort of serious radar navigation I've read about, with radar as the primary means of position fixing, but it's very good as a cross-check against GPS. I would not plan to make a passage where GPS was the sole way of avoiding an obstacle (for example in Pete's post #3, in theory you could drive a boat into an unseen Fowey harbour on the plotter alone, but most would consider that irresponsible) - but with radar overlaid on a chart, even if you're not formally plotting ranges and so on, as long as the echos line up with the charted land you have an independent cross-check of the GPS position. As long as that's the case, one can legitimately "drive the little boat across the screen" in reasonable safety.

Pete
 
dunedin said:
In 10 years time radar may be much less valuable (like a sextant)
Click to expand...

Not disagreeing, but it's worth remembering that the technique of "GPS to avoid stationary things, AIS to avoid moving ones" is 100% dependent on one source of data, namely GPS. A fundamental tenet of navigation is that one should not rely on a single source.

Pete
 
You must log in or register to reply here.

Other threads that may be of interest

M
Adding radar - on pole or arch?
2 3 4
Replies
74
Views
2K
Marsali_1
M
W
Downsizing to your boat.
2
Replies
28
Views
740
Wansworth
W
R
My boat trip hopefully in May Around Scotland
2 3 4
Replies
65
Views
2K
RobBradley
R
B
teak laid decks?
2
Replies
22
Views
921
lustyd
lustyd
R
Moving on.
2
Replies
29
Views
1K
Greg2
Greg2

Share this page

Top