How to prevent PSS seal water from freezing

[kingofcary]

Hi All .. my question is around winterizing to avoid freezing systems. My boat will remain in water year round but periodically it can get below freezing. In particular my question is with the PSS shaft seal. Never had one before but it has what I figure is a fresh water connection for lube as well as cool. What do I do to prevent the water in that line from freezing ? Much appreciated .. Dennis

[ranger58sb]

Our raw water system includes cooling water from the raw water pump to the shaft seals. IOW, our shaft seals are not cooled by fresh water, but rather by raw water.

When we winterize, antifreeze running through our whole system goes everywhere... from strainer to raw water pump, oil cooler, fuel cooler, trans oil cooler, aftercooler, heat exchanger along one path, and from raw water pump to shaft seals on another path.

-Chris

[kingofcary]

Ranger42c .. thanks for the reply. That does make sense. I believe the raw water for seal come off line for engine so I guess that is covered as you say when I winterize the engine intake. One item I see is that my ac/heater has its own separate raw water intake and pump so that won’t be covered from the engine intake . I suppose to address that I loosen the ac water filter just after the intake and it drains “downhill” ? Thanks again .. Dennis

[mike d.]

I have a problem with the thought process, about the winterizing anti-freeze going to the shaft seal, and staying in a strong enough solution to not freeze ! If seal area is open to raw water under boat, it would dilute the solution when it makes contact no? The only way to stop that from happening is if the seal area was not in direct contact with the raw water !

[ranger58sb]

Originally Posted by kingofcary

Ranger42c .. thanks for the reply. That does make sense. I believe the raw water for seal come off line for engine so I guess that is covered as you say when I winterize the engine intake. One item I see is that my ac/heater has its own separate raw water intake and pump so that won’t be covered from the engine intake . I suppose to address that I loosen the ac water filter just after the intake and it drains “downhill” ? Thanks again .. Dennis

Yeah, A/C system is different. On that, I use a transfer pump to inject antifreeze at the same time as the A/C raw water pump is running, until AF flows out both discharge ports. OTOH, If I only had one A/C (hence only one discharge path), it'd probably be simpler... the transfer pump would do it. (In our case, unless I run both at once, the AF only exist via the shortest of ther two discharge routes.)

Easy enough, in any case.

Originally Posted by mike d.

I have a problem with the thought process, about the winterizing anti-freeze going to the shaft seal, and staying in a strong enough solution to not freeze ! If seal area is open to raw water under boat, it would dilute the solution when it makes contact no? The only way to stop that from happening is if the seal area was not in direct contact with the raw water !

In our case, raw water outside the boat isn't usually cold enough to freeze, and I help that along by running a deicer when it looks like our harbor will freeze over. Not sure that's strictly necessary, since the movement of the boat will keep water under the boat from freezing. Here.

-Chris

[Kenr74]

Interesting question. I took mine all apart this year as I was measuring for replacement bellows, so no worries there. I was under the impression that as it operated, water ran from the cooling line, and out of the boat around the shaft. So if you haul the boat, I would assume the water would run out. I didn’t notice a significant amount of water when I disassembled mine (although I wasn’t paying close attention).
In regards to staying in the water, I can’t imagine it getting frozen enough to do major damage as it is all rubber, so long as you had some sort of deicing for the boat.

[ArmyDaveNY]

There are different ways to handle this depending upon where you are and if the boat is spending time in a marina or on the hook. If you are in a marina and you choose to use shore power you can put a heater in various parts of the boat. Depending upon what latitude you are at you may just need a little heat to prevent freezing.

Does the PSS have an attachment? Some have an attachment that allows water to get added to the seal to keep sediment from damaging the machined surface. If you do have this are you able to put antifreeze in it?

What does the manufacturer suggest?