Inboards

[Capn Skippy]

Hi, new to inboards having come from an I/O express cruiser.

My question deals with a vessel taking on water-

I understand both shaft seals and rudder boxes will drip water into the bilge. Is that exclusively while underway, or will running in neutral also drip? What about just sitting tied to a dock or in a slip... will there be some amount of water showing up?

Thanks,

Mark

 

[sdowney717]

with flax packing shafts drip mostly when running, should not drip otherwise, but it might a littlebit.
You can switch to GFO marine packing which does not drip, sitting still or moving thru the water. I put mine in 20 years ago, and it has not worn out, and it does not drip, same packing for 20 years. I also did the rudders.

 

[Capn Skippy]

with flax packing shafts drip mostly when running, should not drip otherwise, but it might a littlebit.
You can switch to GFO marine packing which does not drip, sitting still or moving thru the water. I put mine in 20 years ago, and it has not worn out, and it does not drip, same packing for 20 years. I also did the rudders.

Thanks Downey... the shop that did some work on water leaks (heat exchanger was leaking, and a rudder box was what they called dbl the speck but unconcerning) has the boat back now as over the weekend bilge pump kicked in every few hours (okay, maybe a bit of an exageration, but several times over the weekend while @ a dock) to re-evaluate what and where water's coming from.

They thought it was probably shaft seals or stuffing boxes just doing there thing. I disagreed heh.

 

[rslifkin]

With PTFE or flax packing, the shafts will drip while turning. Depending on how they're adjusted and condition of the packing, they may drip a little while stopped as well. Drips while stopped shouldn't be enough to put a significant amount of water in the bilge, however.

 

[Scrib]

Yes, stuffing boxes will leak but one filled with flax packing should only drip about once every minute or so - at the most! This would be underway and possibly at rest. They should NEVER leak enough to kick on the bilge pump even once/day ... once/week would be pretty unusual even. All that being said, stuffing boxes, whether prop shaft or rudder post, need to be maintained. This could be simple visual check each season for excessive leaking or opened up to check the packing. Flax packing generally needs to be refreshed every few years while some of the newer packing material might go 10+ years without replacement. I replaced mine the first time after 10 years simply because the shaft was pulled to replace the hose on the stuffing box. After a couple of adjustments as the packing broke in it hasn't been touched in about 5 years now and drips only in a very minor way. That's my $0.10.

 

[rslifkin]

In general, stuffing box drips shouldn't be enough to cycle the bilge pump even once a week at rest. But under way, every couple hours of motoring would not be unusual at all, depending on how fast your shafts spin, the packing material used, how safe you play it on tightness / temperature, and how much water it takes to trigger a bilge pump cycle.

 

[OldDan1943]

This is a good reason to have a bilge pump counter. This comes in handy of you leave the boat unattended.

Always refreshing to see all zeros when you return.

IF a/the bilge pump counter reads more than one or two, time to start investigating.

Always check your high water alarms prior to getting underway.

 

[Comodave]

We use Duramax in ours. They don’t drip either underway or at the dock. I replaced the port side last winter and am still breaking mine in, about 10 hours, but with the virus we haven’t used the boat this summer. I will replace the starboard side this winter when I have the starboard engine out. I rebuilt the whole stuffing box on the port side last winter and will do the starboard side this winter. New hose, clamps and stuffing (Duramax). Then I probably will never have to mess with them again.