Mast leak h40.5 Solved!

Feb 10, 2004
4,097
Hunter 40.5 Warwick, RI
Three years ago I pulled the mast in my h40.5, and ever since then I have had a water leak down through the wire bundle that is inside of the mast. I was not present for the mast re-stepping (that was a mistake) and the wires were not successfully sealed by the yard.
Not wanting to pull the mast again, I attempted several times to seal the wires from inside the main cabin, and no attempt was successful until now.
The wire bundle comprised of the VHF cable, TV antenna, wires for the steaming, fore-deck and anchor lights, and the signal cable for the wind transducer pass through a piece of PVC tubing that is sealed through a hole in the mast step. This PVC tube is just long enough so that the top end inside the mast is about 1" above the base of the mast step. In theory, any water that runs down the inside of the mast would run out of drain holes at the mast base before it could become deep enough to enter the top of the PVC tube.
However, if water runs down the wires, there must be a complete seal between all of the wires and the inside of the PVC tube otherwise the water will run through the tiny passages between the wires and leak out into the cabin. This is the problem that I had.
So this spring I was determined to re-seal and stop this leak once and for all.
I pulled the PVC tube out of the mast step and into the cabin. I cleaned off most of the old sealant from the wires and the tube. This was surprisingly easy. I then laid all of the wires to be parallel and placed a hose clamp snugly to hold them in place above where the PVC tube will be secured. Using Sudbury Elastomer 321 Sealant, I liberally applied the sealant to each individual wire for a length of 4", and as each wire was coated with sealant it was laid back parallel in the bundle. After all of the wires were coated thoroughly, a couple more hose clamps were snugly applied over the 4" length. After this was cured (24 hours) I replaced the hose clamps with wire ties and then coated the outside of the wire bundle with more sealant - twice. After another day a final coating was applied and the PVC tube was slid up over the bundle and the wire ties and more sealant was applied at the top of the bundle and over the top of the PVC tube as well as up into the bottom of the PVC tube. A wire tie was placed at the top of the bundle that would stop the PVC tube from moving upward on the wires when the entire tube was pushed up into the mast. A day later, the outside of the PVC tube was coated with this same sealant and the tube was pushed up until it was just 1/8" down from the cabin top. This position put the top of the PVC tube about 1" above the mast step. It was left to cure for several days.
Finally I tested by hosing at the bottom of the mast and found no leaks. Previously pouring water around the mast base did produce leaks coming between the wires inside the cabin. Then I climbed up the mast with the hose and poured water into one of the halyard exit slots. I observed lots of water being expelled from the weep holes at the mast base, but no water inside the cabin.
I think I have nailed it. Attached are some pictures during the process.
I know that other h40.5 owners have had this leak problem and other Hunter boats may have the same method of cable pass-thru.

I think the secret of sealing the wire bundle is to apply sealant to each wire and lay the wires parallel with more sealant around each wire so that there can be no spaces between the wires for water to pass.
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Rick D

.
Jun 14, 2008
7,182
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Wow, nice job Rich! I've never had mine down, but when I do I'll know what to do. Thanks.
 
Jun 1, 2009
1,822
Hunter 49 toronto
More ideas

Ok, I solved my 40.5 leak in a very different, and somewhat sneaky way.
Yes, the original pvc pipe was problematic.
It was , as you mentioned, supposed to be proud of the mast step, so that water wouldn't drain down.
But, I didn't want to pack the pipe with sealant, as it was a bit of a guessing game, and it would make pulling the spar again very tricky
Here is what I did:
I took a small plastic funnel and cut a hole in the spout just big enough for all the wires to go through.
I inverted the funnel, (spout facing masthead), and passed all the wires through.
Then, I packed the spout with 4200.
When I installed the mast, I simply led the wires down the pvc pipe, and made sure the open end of the funnel sat on top.
All water running down the wires simply ran down the outside of the funnel, and drained out the mast step

Important note!!!!
One of the reasons that the 40.5 mast will still naggingly leak into the cabin liner is because a ton of water literally builds up inside the mast (in a bad storm it can be significant), and overflows the pvc pipe.
Drill drain holes between your mast base and the deck step plate !!!!!
I put in two 1/2" holes, and the water literally pours out when a storm hits.
 
Feb 10, 2004
4,097
Hunter 40.5 Warwick, RI
Art,

Good idea about the funnel, but you can only set that up when the mast is down. But I will look at drilling a couple more holes for drainage.
 
Jun 1, 2009
1,822
Hunter 49 toronto
Yes, the holes are critical.
Little tough to do neatly. I ended up using a small file to clean up the hole.
If memory serves me, the best place to drill is on the forward edge, but don't quite me,
It has to be a spot where the mast extrusion is clear of the mast base "shoe"
 
Jun 13, 2004
90
Hunter 40.5 Hampton,Virginia
Rich, great job and thanks for the information. Please submit it and put it in the modifications section .
 
Mar 26, 2015
109
Hunter 376 Marina del Rey
Rich,
You win the Hero Badge of 2019! It almost looks and sounds easy.

Fair Winds!

Tim
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
22,812
CAL 35 Cruiser #21 moored EVERETT WA
I applaud Rich’s design. It solves the problem when the mast is up and the leaks appear.

with my mast down, resolved the issue with a hose around the line to stop accumulated water from topping the tubes, a drip loop in the wire so water did not flow down the wire, and 4200 sealant around the tubes running into the deck.
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the wires in the picture were the old wires from before ours refit. They were cut off and tops filled with 4200 to prevent any leaking.
 
Feb 20, 2011
8,048
Island Packet 35 Tucson, AZ/San Carlos, MX
I think the secret of sealing the wire bundle is to apply sealant to each wire and lay the wires parallel with more sealant around each wire so that there can be no spaces...
Well, that secret's out of the bag. ;)
 

BrianH

.
Feb 14, 2005
104
Hunter 44 LaSalle, MI
I had the same issue with my h336. It was very frustrating , especially since the yard guy told me the only solution was to keep pumping the hole full of silicone from inside the cabin.

I noticed that newer boats (the h340 was basically the same boat) used a mast wire port that mounted on the deck in front of the mast that solved the problem of accessibility. I ordered a mast wire port from Hunter and waited patiently for the end of the season to solve the leak. I pulled the mast along with the wiring and gobs of silicone. Since it was a PVC tube, I went to the local hardware store and got a proper sized PVC cap and capped off the tube. I then notched the base of the mast itself to match the water outflow channel in the mast base. When I reinstalled the mast, I pulled the wires out through that notch (installing a rubber grommet to protect the wires from the mast edge).

Now the fun part, I drilled a hole in the deck for the new mast wire port. I made sure that it was in an area that was close enough to the mast that I could get to it through the inside access hole near the compression post. I then installed the port and fished the wires through. Everything worked and there we no further leaks for the 4 years . I figured even if this new setup developed a leak, it would be a simple process to recaulk and not involve pulling the mast.

I think the wires were long enough to reach the junction block but to be fair, it's been more than 15 years since I did this and have long ago sold that boat.