Blanking Plug Fun??

Ransom · 10-25-2018, 09:52 PM

Looking for a little assurance, that it's not Too tough to Pull the Tranducer Unit from the Airmar DT800 housing it is in, and QUICKLY insert the Blanking Plug. The Depth Finder/Temp sensor appears to Not be sending information to our Raymarine SeaTalk network, and I wanted to pull to inspect & clean before ordering a new unit. Any Suggestions?
Thanks,
Kim

dhays · 10-25-2018, 10:08 PM

Be quick and don't fumble the plug?
Make sure your bilge pumps work?
Ensure your boat insurance is paid up?

Seriously, I've never done it on one of my boats but I know folks that have and they keep telling me it is no big deal and they haven't had a boat sink yet.

Seevee · 10-25-2018, 10:58 PM

I could argue to be SURE that the replacement plus is well greased so it will slide in without issue.

koliver · 10-26-2018, 12:01 AM

When you pull the plug you will have a hole the diameter of the plug, water pressure will be enough to raise a spout of water as high as the waterline until you stop it. In that 2 seconds before the blank goes in, enough water will pour in to fill a water glass, maybe 2. If you relax a little, you will be able to change out the plug for the blank and you wont get very wet.

Brisyboy · 10-26-2018, 03:41 AM

I agree, no big deal and something sailors do regularly - on our previous racing/cruising yacht I always took the paddle wheel of the B&G instruments out before and after each days outing- perhaps a touch more than 2 glasses full but nothing to increase the pucka factor for - in fact occasionally I used to deliberately let more water in than necessary just to give the bilge pumps some exercise

psneeld · 10-26-2018, 03:55 AM

Does that transducer have a small flap that shuts off the hole when you pull the core like the older ducers?

If so it is REALLY no big deal as long as you have a plug with lubed, good o-rings on it.

Less water than a stuffing box repack in the water.

If the plug fails to seal completely, even the tiniest bilge pump will handle it fine.

It's really no big deal or they would never sell any.

ranger42c · 10-26-2018, 07:11 AM

The transducer we have that uses a DST800 insert does NOT have the flap valve to block water inflow.

OTOH, it's not a huge problem to pull the DST800 and insert the blanking plug. I've layed out some rags in advance, stopped up a nearby limber hole just to keep water from migrating too far... but otherwise it's not a big deal. I'd say just have a look at orientation in advance, to know how to be holding and inserting the blanking plug easiest/fastest. Happens we just replaced our DST800 'cause the depth readings were going squirrely.

Our other depth finder transducer does have that valve, and it's a nice feature.

I think I maybe saw recently that there's a newer trandsucer than ours that uses the DST800 and does have the valve... but if true but that's not the one you have... that's not much help.

-Chris

Ransom · 10-26-2018, 07:28 AM

Thanks ALL for the Info/Encouragement. I will definetly have to create some space to accomplish this quickly. Took me a while to even find it. It was in the engine room, under the deck plates, but also under the house battery boxes that were bolted to the floor. Oh, and a piece of the deck plate support frame is almost directly over the transducer with 2" of clearance - SO, that has to come out too. I would like to have a word with the Genius who thought this was the best location. Thanks Again ALL!!!
Kim

Maerin · 10-26-2018, 07:33 AM

A small point, make sure your lube is non-petroleum based. Silicone grease is great. Vaseline is bad, it will cause the O-rings to soften, swell, and get very difficult or impossible to remove. Vaseline belongs in the head, not the toolbox.

**Larry M** · 10-26-2018, 07:44 AM

We’ve done it several times. I have a small towel handy. I unscrew the transducer retaining ring. As I remove the transducer quickly, I put the towel over the hole. Next, I get the plug ready and do the reverse. I found I don’t get that much water or at least I’m able to stop the vertical geyser.

I do this even with the transducers that have the flap.

Bkay · 10-26-2018, 08:44 AM

The first time I did this I had a friend with me. After fumbling with the blanking plug for what seemed like 30 minutes (actually about 5 seconds) his only comment after we got her sealed was "that seemed like an alarming amount of water."

Be ready for the shock of how much water enters the vessel, stay cool, and remember - slow is smooth and smooth is fast! You should be fine.

alormaria · 10-26-2018, 08:47 AM

Take off your shirt before pulling the plug.

You'll find out.

bayview · 10-26-2018, 09:23 AM

I always keep rags nearby to stuff in the hole if all else fails. Never had to use them though.
There isn't much pressure. At 3' below water line it would be 1.5 PSI

Ransom · 10-26-2018, 07:03 PM

Well, got the Transducer Out and the Plug In. Cleaned the transducer, swapped them back out and NO signal. Ordered a New Transducer - be here Tuesday. Thanks Again Everyone for the Kind words and advice. Much Appreciated.
KIM