Stop wires slapping inside of mast?

Nov 15, 2015
268
J J/30 Seward, AK
I have a J/30 where the wire harness is apparently loose inside the mast which allows it to slap with the waves at night. A no-go for sleeping. I know it's the wire harness because I can grab it near the bottom of the mast and affect the noise.

Any ideas on how to stop the noise? Seems like a pretty poor design if it is indeed original. My dad says his J/35 had a conduit that prevented this problem, though that sounds like a big job.
 
May 17, 2004
5,031
Beneteau Oceanis 37 Havre de Grace
One trick is to put zip ties on the wires every few feet and leave the tails on the ties. The tails help hold the wires off the mast. But that still involves pulling and rerunning all the wires. Not sure if there are any ideas that don’t involve that.
 
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Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
If you can remove your mast maybe you could add and secure your own conduit. Zip ties work until they break. I tried swim noodles taped together and wires inside. Then you’ll get some access to the wires if you need to replace any.
 
Sep 24, 2018
2,549
O'Day 25 Chicago
If you have a halyard and your standing rigging is not connected to the masthead maybe you could go aloft, remove the masthead and work some pool noodles or pipe insulation into the mast? I know this isn't likely to work out in reality
 

Bob J.

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Apr 14, 2009
773
Sabre 28 NH
Dropped my mast last fall, this spring pulled new wiring & a vhf coax. Bundled the wiring together & sleeved them in "rubber" unsplit pipe insulation. Worked like a charm.
 
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Apr 8, 2011
768
Hunter 40 Deale, MD
One trick is to put zip ties on the wires every few feet and leave the tails on the ties. The tails help hold the wires off the mast. But that still involves pulling and rerunning all the wires. Not sure if there are any ideas that don’t involve that.
We did this to an old Catalina 27 that was just embarrassing to be tied up next to anyone the mast slap was so bad. It did require the stick to be pulled and all the wiring to be pulled out, but it worked extremely well for 8 years until we sold the boat. Very cheap, expedient solution but worked well. If you do it just make sure you "spiral" the zip tie tails so they cushion the wire bundle in all directions. The beauty of conduit, however, is you can later replace old wires or run new wires without pulling the stick and the wires out again.
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
Noodles and zip ties are a temporary fix. They have the disadvantage of conflicting with halyards in the mast.

Noodles eventually degrade to noodle dust. Clog the base of the mast blocking the weep holes, letting water fill the mast till it leaks inside the boat.

The best modification is done with the mast down. An inexpensive length of PVC pipe to serve as a conduit for the wires. Use a diameter 1 1/2 times the size of the wire bundle Attach the conduit to the mast using aluminum rivets. Problem solved.
 
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Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Noodles and zip ties are a temporary fix. They have the disadvantage of conflicting with halyards in the mast.

Noodles eventually degrade to noodle dust. Clog the base of the mast blocking the weep holes, letting water fill the mast till it leaks inside the boat.

The best modification is done with the mast down. An inexpensive length of PVC pipe to serve as a conduit for the wires. Use a diameter 1 1/2 times the size of the wire bundle Attach the conduit to the mast using aluminum rivets. Problem solved.
How do you get above the first spreader? We have spreader lights, a forward deck light, and a VHF antenna for a radio tuner on that spreader.
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
@All U Get , You have two options.
  1. Run two conduits. One runs from the mast head to the mast base for the mast head electrical. Two runs from the base to the spreaders
  2. Run conduit from mast base to spreader. Take out the wires you need there. Run second conduit from above just above the spreader to the mast head. It carries the electrical at the mast head
Both systems work. Easy to do with the mast down on the hard.
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
@All U Get , You have two options.
  1. Run two conduits. One runs from the mast head to the mast base for the mast head electrical. Two runs from the base to the spreaders
  2. Run conduit from mast base to spreader. Take out the wires you need there. Run second conduit from above just above the spreader to the mast head. It carries the electrical at the mast head
Both systems work. Easy to do with the mast down on the hard.
I’m still mulling this over, what holds the conduit against the inside of the mast when you try to drill a hole for the pop-rivit?
 

DougM

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Jul 24, 2005
2,242
Beneteau 323 Manistee, MI
How do you get above the first spreader? We have spreader lights, a forward deck light, and a VHF antenna for a radio tuner on that spreader.
My mast had 2 conduits. The first went as far as the spreaders ( to a mast exit for the steaming light/deck light wiring,. The second went all the way to the masthead .
 
Feb 5, 2009
255
Gloucester 20 Kanawha River, Winfield, WV
Noodles eventually degrade to noodle dust.
Mine are going on 10 years old and the only degradation has been half an inch or so at the bottom of my mast where the foam is exposed to sunlight when the mast is down. I cut off the bad part and started covering the end of my mast when I put my boat away for winter to get around this.
 
Jun 8, 2004
994
C&C Frigate 36 St. Margarets Bay, Nova Scotia
My previous boat had a channel in the mast extrusion that was accessed by sliding out the mainsail track; this is the way all masts should be designed! However, my current boat was like the ones in this thread and I debated how to tame the wires slapping. I installed two conduits in the mast last Spring. It was a bit of a tricky, two-person job, but it totally stopped the wires slapping. I used 3/4" PVC conduit and ran a bead of polyurethane adhesive along one side as it was fed into the mast that was lying on saw horses. Once in place, the conduit was rotated to put the glued side down against the mast. After a couple of days of the glue curing, the conduit was fastened with aluminum pop rivets, set about every three feet. Then new wires were pulled, using messenger lines.
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
I was thinking about using a sort of air bladder to inflate and pin the tubing against the inside. It just has to keep the tubing in place for drilling and pop rivets, then deflate and move further inside.
 

LloydB

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Jan 15, 2006
806
Macgregor 22 Silverton
I don't think getting a piece of conduit fastened down inside the mast would be a problem with the mast down. A one inch PVC conduit 60 feet long weighs about 20 pounds.You could hang that pvc from a single 3/16 inch rivet from only the top all year if you wished. You could actually support the entire length of the 20 foot conduit with that same rivet from the bottom since the wire inside is only contained it would not be supported anywhere vertically by the conduit . The entire conduit could be supported from the bottom only but the top could wiggle and turn the entire assembly into an experiment. Drilling into the PVC with a nice sharp drill should not be any problem if you have first drilled the mast and verified the PVC final position by inspection. If you are concerned about pushing the PVC up with a dull drill bit you can hold it down inside the end of the mast with a stick.
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
what holds the conduit against the inside of the mast when you try to drill a hole for the pop-rivit?
In my case, we started at the open end of the mast. We reached inside and held the conduit to the mast at arms length. Kind of like reaching into the business end of a mare - artificial insemination - but with out the long glove on your arm.

Once you drill and pop rivet one you can progress up the mast a bit at a time adding additional rivets. You do not need to go go the entire distance. Say 3 at the top and maybe in the middle and near the base.

You can also reach inside my mast with a two by four putting pressure on the conduit to hold it in place.

With the mast on the hard supported by saw horses, it was a lot easier than hanging from a halyard.
 
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Blitz

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Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
I would think that the end is a pop rivet inside a conduit, has the potential to tear the insulation off your wiring when you pull it through so be careful with this setup.
 
Jun 8, 2004
994
C&C Frigate 36 St. Margarets Bay, Nova Scotia
I would think that the end is a pop rivet inside a conduit, has the potential to tear the insulation off your wiring when you pull it through so be careful with this setup.
There's not really any sharp edges on the flared (inside) part of an aluminum pop rivet. I pulled a substantial amount of the top end of a multi-conductor radar cable out of the conduit at the spreaders and saw zero evidence of abrading or tearing. Note that the outer insulation on the radar cable is considerably thinner than the jacket on common DC multi-core wire.
 
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