Best way to pass antenna cable through deck?

[Tedd]

The photo below shows the connector for the VHF antenna cable that was installed on my boat. This is the connector where the cable passes through the deck on its way to the mast.

For reasons I won't go into, I need to relocate where the cable penetrates the deck. But I got to wondering if this particular connector is even the best one to use. The flange area seems small to ensure a water-tight seal and, as you can see from the photo, it's not even very flat. (Though that could be corrected.) Is there a different kind of connector I should use?

I've also seen the cable passed through a cable gland. Is that a better solution? I probably have enough slack in the cable to allow that.

Since I'm basically starting from scratch here I want to do it right.

[Nekton73]

I am a fan of a simple 'swan neck' entry pipe for mast related wiring, however there are many varieties of cable glands available as well.


An example of options: https://www.seascrew.com/browse.cfm?...-&l=0000000668


Unfortunately I don't have a good picture of my own swan neck pipe, but here's a partial shot. It is just a 1.5" stainless pipe with a flange welded to it, and then two 45° pvc elbows fitted over top to form a 90° bend. Friction fit only, they have never come loose and if pressed firmly are truly a bear to remove at the end of season when it comes time to unstep the mast. Never had water enter, although I suppose a heavy boarding wave or complete submerging would change that. The same would apply to dorade vents I suppose.

[capt jgw]

I've used flange type successfully, but the flange may have been a bit bigger. If you have enough cable to reach, a gland is better as there are fewer connections to cause problems. The flange type or the standard double male splicer adds two connections for each splice. The fewer the better. On a boat that gets it's mast lowered often like a trailer sailor you would want a splice at the mast, rerouting the cable each time would be too much of a pita. At least I wouldn't want to do it.

[Tedd]

@Nekton73: I hadn't seen the gooseneck style before. I like it but I might not have enough cable.


@capt jgw: Yes, it's a trailer sailer so I need a disconnect at the mast, above deck. (This already exists. I'm just modifying what's there.) So, to eliminate one connection, I'd have to replaced one of the existing cable-end sockets with a plug. That's not a bad idea though. I might consider doing it. But a flanged connector that won't leak would be easier.

[Marathon1150]

I was told by a very fussy engineer who was also a serious radio geek (disclaimer: I am neither but have not seen any evidence that he is wrong) that given the importance of the VHF radio as a safety item on board that maximizing signal strength is very important. He believed and his views were well supported by signal analyzers, that every coupling introduced into a vhf antenna cable could reduce signal strength by an amount large enough that it should be avoided. His strongest recommendation was to use a single run with no connectors from the antenna to the radio. So that is what we have - the cable goes through a Blueseas cable gland at the foot of the mast. Fortunately we have only had to take the mast down a couple of times since installing the cable in this way. The previous owner used a deck gland followed by a coupler.

The radar cable is a completely different story and I really wish that I had not opted to put the radar on the mast. Each time that the mast has been dropped, we have to cut the cable and then solder the wires together when the mast goes back up.

[Thatjuiceguyy91]

Hey so this coaxial connector could be used but the bent shape looks damaged.
It’s probably ok but I’d test for continuity between the sides before attempting to install.
On an airplane passing wires through structure has a couple things worth noting.

1) is whether the pass through is pressurized or not , not something a boat contends with in the same sense, how ever water level is a physical condition worth being aware of.

2) if it’s pressurized there is a hole made so imagine cutting a round hole in a sheet metal piece, now a piece gets put in the hole that makes a slot that will be fed wires and then sealed with B1/2 sealant.

If the coaxial line can be fed through and secured so no vibration and what not the connector wouldn’t be needed. Every connector added lowers the signal strength. The coaxial lines themself affect the signal strength too.

It really depends on the specific location how to proceed. Just make sure the line is secured ( zip ties are used on aircraft most commonly )

I hope I provided some value and if you have any questions about anything I mentioned or didn’t , let me know I’d be happy to help.

[s/v Jedi]

The swan neck is the best option.
https://www.amazon.com/dp/B094R928LJ

One single cable run isn’t the best option. From the antenna into the boat is one run and from the point under the mast to the radio is the second run. Where these two runs meet, somewhere below the mast, couple them using a lightning arrester. You need a lightning rated bonding plate for this.

[deblen]

Originally Posted by s/v Jedi

The swan neck is the best option.
https://www.amazon.com/dp/B094R928LJ

One single cable run isn’t the best option. From the antenna into the boat is one run and from the point under the mast to the radio is the second run. Where these two runs meet, somewhere below the mast, couple them using a lightning arrester. You need a lightning rated bonding plate for this.

I agree. Here is Cdn source https://www.amazon.ca/Gooseneck-Wind...s%2C378&sr=8-3

[Tedd]

Thanks everyone for your comments.

Just to clarify, it's not an option to have an unbroken run. This is a trailerable boat and the mast comes down every time I sail, requiring the cable to be disconnected at the base of the mast.

If I replace one of the cable-end plug fittings with a cable-end socket fitting, then I could eliminate one connection by using either a cable gland or a goose-neck pipe through the deck.

[Toccata]

I have mostly used the gooseneck option and then tuck butyl sealant, purchased in strips around and between the wires (in the opening above the deck). Its a bit clunky looking and can catch a flailing sheet.
I have also used a simple 45deg pipe facing up towards the mast, and in that case "jammed" butyl tape into and around the wires again with no leaks.
The sealed wires are retrievable with a bit of digging and scratching to get the butyl out.

I don't mind the deck glands sold by scan strut, but I haven't worked out a good/neat technique for drilling holes in the nylon inserts.

[Wotname]

Yes a swan neck is an excellent solution but it maybe overkill for a trailer boat. How often are you removing the mast (coax connector), once a season, once a week, daily?

If the connection has to be removed more often than monthly, I would probably use a through bulkhead connector as shown in the OP but I would first mount it on a larger plate and then contour the large plate to the deck contour. Being pernickety, I would use N type connectors at this point as they are intrinsically more weathertight but if that is a bridge too far for the OP, then seal the PL-259 (UHF) series with tape of choice.

[Tedd]

Originally Posted by Wotname

I would first mount it on a larger plate and then contour the large plate to the deck contour. Being pernickety, I would use N type connectors at this point as they are intrinsically more weathertight..

Those are excellent ideas, thank you very much.

Yes, I disconnect the cable every time I sail, so dozens of times a year. Fortunately, the manufacturer has provided a raised, flat area for deck penetrations, so it shouldn't be too difficult to get a good seal.

[Old Pop David]

Just keep water off the connectors while in storage. Use the larger RG-8 (or is it Rg-6, been out of the business too long) coax for longer runs and extension. The thick coax that is about 3/8"/9mm diameter. Too many feet of RG-58 will cause more signal loss then a connector joint. The bottom line is antenna height more so then radio power for how far your signal goes.

[Wotname]

Originally Posted by Tedd

Those are excellent ideas, thank you very much.

Yes, I disconnect the cable every time I sail, so dozens of times a year. Fortunately, the manufacturer has provided a raised, flat area for deck penetrations, so it shouldn't be too difficult to get a good seal.

And get a couple of dust caps like these
https://www.amazon.com/Ancable-2-Pac.../dp/B07GKKJNYW

[Tedd]

I thought I had settled on a solution but I'm not sure I can get what I need to make it work. Below is my current set up (on the left) and what I was planning to do (on the right).

What I like about the proposed configuration is that it eliminates one of the two existing connections. But it depends on being able to put a socket (female) on the end of the cable instead of a plug (male). I haven't so far been able to find a source for a socket cable end and I'm beginning to wonder if such a thing even exists.


Does anyone here know of a source for cable-end socket connectors or can you confirm that there is no such thing?