B&G Plastic Through Hull?

[wscotterwin]

My boat is a Brewer 44 Cutter and I am looking to install a new nav system. B&G looks to be the system but I am curious about the Plastic through hull for the Depth Sensor (DST800). Should I be concerned about plastic vs brass? Nothing else on this boat is plastic and I intend on extend cruising on this boat.
Thoughts?

[Ringmaster]

Don't worry about it. It's probably made using engineering plactic. Not the same stuff as your toothbrush.

[Orion Jim]

Originally Posted by wscotterwin

My boat is a Brewer 44 Cutter and I am looking to install a new nav system. B&G looks to be the system but I am curious about the Plastic through hull for the Depth Sensor (DST800). Should I be concerned about plastic vs brass? Nothing else on this boat is plastic and I intend on extend cruising on this boat.
Thoughts?

It’s just an Airmar unit. You can specify it in either plastic, bronze, or stainless steel.

http://www.airmartechnology.com/uplo...res/DST800.pdf

[tanglewood]

I think only the plastic tube has the build-in flap that closes when you remove the transducer core, thereby sorta kinda allowing you to replace it while in the water. And you will need to replace it when it breaks, typically with a loss of temp in 1-2 years.

[Orion Jim]

Originally Posted by tanglewood

I think only the plastic tube has the build-in flap that closes when you remove the transducer core, thereby sorta kinda allowing you to replace it while in the water. And you will need to replace it when it breaks, typically with a loss of temp in 1-2 years.

Only the housing material differs, not the design. Plastic, bronze, or stainless, all have the “flap”.

[billknny]

Originally Posted by wscotterwin

My boat is a Brewer 44 Cutter and I am looking to install a new nav system. B&G looks to be the system but I am curious about the Plastic through hull for the Depth Sensor (DST800). Should I be concerned about plastic vs brass? Nothing else on this boat is plastic and I intend on extend cruising on this boat.
Thoughts?

First, none are made of "brass", rather bronze.

Many, many boats use "plastic" thruhulls without problems. The don't corrode, or age in any significant way. They also don't blow out if the boat is hit by lightening. Marelon thruhulls and seacocks are very common on long distance cruisers. In fact metal boats will usually use them to avoid corrosion issues.

The only type of boat that should NOT use plastic thruhulls are those made of wood. Swelling wood can crush the plastic. I would avoid them in an engine room, just because they don't do well in a fire, but anywhere else on a boat, go for it.

But if you really are uncomfortable with plastic, you can get it in bronze or stainless as well.

[tanglewood]

Originally Posted by Orion Jim

Only the housing material differs, not the design. Plastic, bronze, or stainless, all have the “flap”.

OK, then maybe it's the long stem that doesn't have a flap? I had a bronze tube and it didn't have a flap. But it was also a long stem version.

[noelex 77]

An option is to install the transducer in a waterproof area. Often it is possible to have a waterproof locker under the V berth. The top does not have to be watertight, it just has to be higher than the waterline at that point (which is not very high).

The risk of the transducer leaking is small but they are often in the bow area where the risk of striking underwater debris is highest. The plastic transducers can also be cracked by poorly placed travel lift straps.

I am surprised more dedicated long distance boat builders don’t take the trouble to incorporate these simple measures at the build stage.