Simrad 4g radar full of water

[Snowpetrel]

Just pulled our faulty radar off the workboat.

It had about 3 inches of water inside it with no obvious sources for the water. And we had to undo the unit to drain it. Dome nit cracked, base clear, seal good etc. Tech guy said condensation, but I find it hard to believe that quality of water got in just from condensation. The unit is about 4 years old, but has only been installed for a couple of years.

I see no obvious drain hole, just some weird bungs at the bottom of the unit that didn't let the water out.

So this is both a warning, and a question. If you have one it might be worth checking, and even drilling a small hole.

Seems they don't make radars like they used to..

[Wotname]

3" of water???? Crikey, that's a lot! I don't buy the condensation explanation, no way.

Maybe the radome seal isn't as good as it looks. Could the radome deform slightly in heavy winds or violent motion (heavy weather) and make the seal faulty.

Driving rain (or spray)???

Was the water fresh?

How high is it mounted?

Still working OK?

Some units do have small drain holes to allow condensation to escape but 3" is a lot.

[Snowpetrel]

Originally Posted by Wotname

3" of water???? Crikey, that's a lot! I don't buy the condensation explanation, no way.

Maybe the radome seal isn't as good as it looks. Could the radome deform slightly in heavy winds or violent motion (heavy weather) and make the seal faulty.

Driving rain (or spray)???

Was the water fresh?

How high is it mounted?

Still working OK?

Some units do have small drain holes to allow condensation to escape but 3" is a lot.

I didn't taste it, but it seemed like fresh water.

The unit is toast.

It was about 2.5 meters above the water.

I guess its possible that water got driven under and then up the seal in strong winds, but It seems unlikely, as the seal is good and it's designed with about 10mm overlap so gravity should keep even driving rain out. I guess water could get in the plug, but the water level seemed to be well above the plug level.

Even shaking it, and turning it on its side I couldn't get any the water out of the unit until I opened it up. Odd...

Anyway not my unit, so I am not wearing the cost, but it does worry me that many other units may have the same issue. The tech guy seemed to think it was pretty normal for these Simrads.

[MV Wanderlust]

Three inches of water that didn't even drip when you shook it or turned it? That's not normal for any brand.

[Nicholson58]

Let’s postulate daytime heating expands the air inside which finds a way to escape. Night cooling causes the reverse. So would rain. If there was liquid water present, it might get sucked in. Sounds like proper drains and vents should be part of the design. I have an early 2G not working. I will check when we return to Trinidad.

[Snowpetrel]

Originally Posted by Nicholson58

Let’s postulate daytime heating expands the air inside which finds a way to escape. Night cooling causes the reverse. So would rain. If there was liquid water present, it might get sucked in. Sounds like proper drains and vents should be part of the design. I have an early 2G not working. I will check when we return to Trinidad.

That makes a lot of sense, I hadn't thought of the warming/cooling cycle sucking water up almost by capillary action/wicking. I suspect the llugs in the bottom are supposed to stop this happening or drain it somehow, but I can't see how they work, and obviously they didn't..

The inside has a substantial aluminum case and scanner. It felt very cold and would act as a big heatsink.

[rourkeh]

I had the same unit and it also filled with water after one year. I called Simrad customer support and after a discussion they had me return the unit. They told me they were having problems with the seals, and sent me a brand new unit. The new unit went through hurricanes Irma and Maria in St Maarten and again filled with water. I guess they have not fixed the seal problem. Not sure what to do now as I doubt they are going to send me another replacement dome.

[Pitchondesign]

I
Water in a radar is not limited to Simrad. My Raymarine unit also collected water. The seals looked OK, and the water was fresh, not salt. I drill some small drain holes at the lowest point in the case, when mounted, problem solved.

[Cadence]

Seems to me having a J trap drain, similar to what an AC condensation pan has, would solve the problem.

[deblen]

From personal experience with various brands of radomes over many years:


If your dome did not come with a drain,drill a 3/16 (4mm) hole clear thru the aluminum cast base & mounting bracket. A good place for this hole is close to the cable gland (rear of dome) at lowest spot.
Driving rain & seawater, during high winds, can leak up by the cover gasket of the flimsy plastic domes used today.
The early domes were of GRP,had a reinforced rim design & rarely leaked. Not so anymore.


The most condensate that I ever saw in a radar was about a tablespoon.That was in an open scanner cast aluminum housing that had been installed on a platform without drilling a hole in the platform fot the rubber drain tube. Temps varied from -10F to + 80F.


My experience / Len

[Dougtiff]

So is the warranty going to be voided if one drills a drain hole ?, probably .

[Dougtiff]

So, if i drill a drain hole in my new 4 G radar, is my warranty going to be voided, probably.

[keith001]

Same problem. Resolved two years ago. The vent and drain , two openings on the bottom, were reversed so that condensate couldn’t drain. Got three units from them before I finally opened the last one before mounting and fixed.

[keith001]

BTW. The vent is the one with the stand pipe, the drain is flush to the case. It breathes when hot and cold.

[Snowpetrel]

Thanks For the replies. Seems this definitely isn't an odd one out. The incorrectly installed drains/vents sound like a likely cause. I'll have a look and take some pics. But it seems like a small hole is the best bet if you have a working example of one of these radomes.