Waterproofing cables through the hull?

How do I install the transducer cable through the hull and keep it watertight?
 
With the power cord, I just removed the positive and negative clips and pulled it through a small rubber gromit that I epoxied into the deck (worked great!). But the transducer has a square-shaped plug that connects to the head unit (Matrix 37). For temporary purposes, I just pulled it through the flush-mount Scotty rod holder and connected it to the FF. It works…but in rough seas, it would surely take on water.

I have searched the archives plenty but it is difficult to find something when you don't really know what its called. What is the waterproofing-gromit-attachment-thingy called? I went to West Marine but they were no help (note: the WM in Monterey is horrible).

Thanks for all the help and suggestions everybody!
PK

I probably should've said "deck" instead of "hull." I am pulling the cables/cords through the deck, just above the footwells.
Thanks!
PK

You are looking for a wire seal.  Check out the last page of the "new school power supply" link.  Craig has a picture what you are looking for.  If you find out where he bought it, pls post.

The wire seal for the battery supply was, I think, West Marine.  But the through-hull piece is slightly different. 

I am pretty sure I found all that stuff at Home Despot, either in sprinkler systems or plumbing.  It's just basically a 1" plastic pipe connector threaded on the outside, with fitting nuts (which screw on both sides of the hull basically locking it in place).  Leaving just enough of the connector on top, I put a fitting threaded cap with a hole big enough for the cable to fit through.  Inside the cap, I just went to Ace and got a few flexible rubber washers that fit tightly around the cable and inside the connector, so when I pull the cable up and through, the series of washers snugs up against the cap hole, limiting any water coming through.  I think it's just a 3/8" hole in the top of the cap, so water hardly makes it through there anyway, with the cable in it.

This, I believe, is InsaneDuane's invention, so he may be able to provide details I forgot.

The tip I got from Sean White:

Your Matrix 37 should come with a 1" plastic ring that is used to line a passthrough hole for your cables.

Drill a matching hole in your kayak that fits this ring snugly. I used a 1" forstner bit, and it was just a tad bit larger than I wanted. 31/32" would have been perfect, but who makes that?

Obtain a synthetic cork from a wine bottle.

Cut this cork to about 1/2" long, now drill it for the two cables, power and transducer. You'll also need to use a razor to slice the cork so that you can slide the cables into the newly drilled holes. Freeze the cork and it will machine easier.

Now, using a bit of Goop or Silicone as a sealant, put the ring in the hole in the deck, the cables into the cork, and the cork into the ring. All these should be good snug fits. The Goop/Silicone is there just to make everything as watertight as a frogs butt.

You should have Goop or Silicone handy, if you are doing any kayak outfitting. So the only part you need to come up with is the wine cork.

Regards,
Scott

I used a "skintop" connector.  These are pretty cool because as you turn the top collar it tightens a rubber sleeve around your wires, waterproofing the penetration.  There are pics of it in the ff power supply thread.  You can get them at most electrical distributors like Graingers.

I always seem to have a little water in the yak due to fish or equipment going in, launching through breakers, or whatnot.  I have my electrical supply sealed in a pelican box and wire seal on top.  I wouldn't hold it under water, but it can sit halfway up in water and I won't have a concern (my yak would need to have several gallons of water inside for this to happen).

But I haven't had a drain plug in the hull since like September.  It's just been an open hole in the top of the bow.  One of these days I will get a new drain plug (dang REI keeps forgetting to ask OK reps for them).  In fact, who was it at the paddlefest at OP last year who said they'd mail me one?  I keep forgetting to call them and ask.

Anyway, if I don't want any drops of water to get on my wires or inside the boat, I'd just keep it in storage.   I am not gonna coat half my hull in goop to keep out a cup of water every hour.  Goop smells and makes my hands sticky, so i have only used it for my transducer capsule.

I am not overly worried about having a 7/8" hole on top of the bow.  However, it looks better with the plug in it, and I feel (maybe rightfully) a little more secure with it plugged, so I WILL get a drain plug soon (before i go out next, hopefully).

If you do the wine cork thingy I do it underneath the Matrix base so you never see it.  Works well or you can use a wire seal. 

Due to the size of the connectors you have two wire seal options for Humminbird units...you will have to either use a huge one, or modify a smaller one...I stock both.

The smaller wire seal will work well for any Eagle 240/245 or similar ff and is very clean and ez. 

Sean,

can you post pics of what these look like?  Do you have one with 3 holes (pwr, t/d, gps) for a Matrix?

I have been running the cables thru the front hatch.  I worked without incident (surpisingly) with my Tarpon tupperware hatch, but I would like a cleaner install for my new boat.

Thanks - Kevin

Kevin,

I picked up one of the smaller wire seals from Sean. It is undrilled. I won't say that putting 3 x 4mm diameter holes in it would be impossible, but it would sure be a tight fit. I estimate the working diameter of the seal at1/2".  I never used it as I sealed my lock-n-lock box by other means.

As Sean mentioned, the wine cork/rub-ring combo was placed under the Humminbird base, so it was protected from being bashed, as well as nicely out of sight. This IMHO would be much more likely to allow for 3 cables.

Regards,
Scott

Ok here's a pic with a quarter for scale...

The biggy has a dome nut opening of 3/4" and the rubber bushing can be drilled and split to any configuration you want.  This will easily swallow a gaggle of cable and the biggest connectors for a ff.  It is big and will not fit in/under the base of Humminbird units.

The middle is the one I use for Eagle ffs, it fits the Eagle/Lowrance units perfectly.  I can be massaged to work with Humminbirds and will fit under the base.  To massage here's what you have to do, it sounds tricky, but it takes about 2 minutes...

1) Drill out the dome nut to make it 1/16 bigger.  The Humminbird cables that will almost fit, will fit now.

2) Now you need to modify the main body of the seal, because the cable ends wont fit throught there either.  Take the nut an o-ring off of the wire seal body.  Carefully cut a fine split in one side of the body with a hacksaw.

3) Now you can use a small screwdriver to carefully pry open the split while you sneak the wires into the body below the plugs.  I have done two wires and three should be fine. 

Remember to assemble in order before sliding the wires into the body or you'll have to do it over.  Assembly order is as follows:

Slide nut down cables
Pass wires through deck
Pass wires through o-ring
Pass wires through split
Reinstall o-ring on seal body
Work seal past plugs and down the wires
Pass wires through dome nut
Tighten body to deck
Tighten dome nut

Or drink a bottle of good cab and use the synthetic cork 

  I can be massaged to work with Humminbirds and will fit under the base.  To massage here's what you have to do, it sounds tricky, but it takes about 2 minutes...

THATS WHAT SHE SAID! lol!
Thanks for all the help/info guys!
Those wire seals look pretty good. I will have to use one on my next kayak modification (recently got a used kayak that is in virgin condition). I actually employed a totally different technique. But I want to make sure it actually works/stands up to the test before posting pics+instrux because it might not even work. I'll be "testing" it this Saturday!

PK

Thanks guys!

my local west marine carries both 'wire seals' and also a lower flush kind of seal called a 'cable clam'.

for $22....

I used one on my boat and it is pretty nice... but I always think about how it cost $22....  .

J

p.s., this thread has pics of it in action...

http://www.norcalkayakanglers.com/index.php?topic=5078.0