Going to dripless shaft?
- Thread starter Valerio
- Start date
Hi Valerio. You may want to search on this because there are several threads about it. Also read MainSail's article. There is more to it than choosing which shaft seal to use. For myself, I went to a LasDrop GenII seal.
I installed a PSS in the spring to replace my 20 year old Volvo seal, not one drop of water, but a hassle to install, wouldn't do it again, as the Volvo seal replacement is only 2 hour job.
You'll find that most people have gone with the PSS seal and there's more history on them then the LasDrop. I attribute this to LasDrop missing the boat, pun intended, because they only made them for larger shafts until recently.
Sliding the seal on the shaft is the easy part. Getting the old transmission/shaft coupling off is a PITA. Some people cut the shaft. Some like me were able to press the old coupling off. I went back with a new split coupling. Then to properly fit and face the two before reinstalling, it opens a whole new can of worms. I'll bet most people forego this part.
But don't let me discourage you. My decision was based on planning for longevity, and my old stuffing box was plastic. Again, this has all been covered in earlier, more detailed discussions.
Sliding the seal on the shaft is the easy part. Getting the old transmission/shaft coupling off is a PITA. Some people cut the shaft. Some like me were able to press the old coupling off. I went back with a new split coupling. Then to properly fit and face the two before reinstalling, it opens a whole new can of worms. I'll bet most people forego this part.
But don't let me discourage you. My decision was based on planning for longevity, and my old stuffing box was plastic. Again, this has all been covered in earlier, more detailed discussions.
I really don't understand the desire to have a dripless seal. I have so many other sources of water that enter my bilge, it wouldn't be dry anyway.
What advantage am I missing?
What advantage am I missing?
That would be the big one. The possibility of improper adjustment of the stuffing box nut is another. I read that some folks measure the heat to be sure they don't over-tighten them. These may not be good enough reasons for you to switch.
I'm not sure but don't most new boats come with a dripless system. That might say something.
@Rich Stidger - my bilge is bone dry. Knock on wood, I did not use the bilge pump in two years (and the last use was for winterisation).
I went with the PSS dripless when I repowered ten years ago. Main reason was that access to the packing nut for adjustment purposes was a royal PITA. If not for that, I probably would have stayed with the nut because of the simplicity of it and the less likelihood of flooding if something should go wrong. Replaced at last haulout two years ago mainly because it was eight years old and I was already on the hard. Like everything else on a boat, they do have to be monitored regularly.
I don't have a dry bilge either. Having said that, the pump doesn't come on and there is no water from the shaft. In fact, if it does come on, it means I have a problem! Probably more of an issue with a boat that is in the water all year.
Have had the PSS on the boat for 8 seasons now. Made the switch to dripless while replacing the prop shaft. Very happy with it so far, no problems yet (knock on wood). But, it's normal to be happy with something until there's an issue. If it ever fails and sinks our boat I'll deny ever writing this.
Couple of thoughts:
To @RichStidger's comment above, if I had other sources of water which prevented our bilge from being bone dry, not sure I'd see the point. We're deck stepped and I like the bilge to be dusty. When it's not, that tells me there's something wrong.
Install it right/or get it installed correctly. Among other details, this includes a properly routed vent line and a security collar inboard of the PSS. Don't reuse the set screws.
Even if one yearns for a dry bilge (or the potential for one), I wouldn't swap out a functioning stuffing box for a PSS just for the sake of it. It's a nice upgrade if you're doing other work, but it's invasive as the shaft needs to come off the coupling which should then be be fit and finished to reinstall. If you have a failed stuffing box or were replacing a strut, shaft, prop, cutlass bearing, etc - maybe think of it.
It's not maintenance free. I always burp ours at the beginning of the season or if the boat has been sitting too long. For me, that takes all of 2 seconds since it's adjacent to our raw water intake seacock. I also try to keep the flange area clean of salt water - again just a few seconds every 4th or 5th time out - I just wipe it with a wet rag when closing the seacock. Last season I had a very small leak - maybe 1/8 the drip rate of a stuffing box. This occurs when debris collects between the stator and rotor. Easy fix, you just use fine grit wet sandpaper (400 or 600) and run it between the stator/rotor. Maybe that took all of 5 minutes. Also, as per the mfg, the bellows needs to be replaced periodically (every 6 years for our model and 8-10 years for the pro). In the Winter I burp it once we're on the hard to try and get any water out of the bellows. Not sure this actually accomplishes anything though.
Couple of thoughts:
To @RichStidger's comment above, if I had other sources of water which prevented our bilge from being bone dry, not sure I'd see the point. We're deck stepped and I like the bilge to be dusty. When it's not, that tells me there's something wrong.
Install it right/or get it installed correctly. Among other details, this includes a properly routed vent line and a security collar inboard of the PSS. Don't reuse the set screws.
Even if one yearns for a dry bilge (or the potential for one), I wouldn't swap out a functioning stuffing box for a PSS just for the sake of it. It's a nice upgrade if you're doing other work, but it's invasive as the shaft needs to come off the coupling which should then be be fit and finished to reinstall. If you have a failed stuffing box or were replacing a strut, shaft, prop, cutlass bearing, etc - maybe think of it.
It's not maintenance free. I always burp ours at the beginning of the season or if the boat has been sitting too long. For me, that takes all of 2 seconds since it's adjacent to our raw water intake seacock. I also try to keep the flange area clean of salt water - again just a few seconds every 4th or 5th time out - I just wipe it with a wet rag when closing the seacock. Last season I had a very small leak - maybe 1/8 the drip rate of a stuffing box. This occurs when debris collects between the stator and rotor. Easy fix, you just use fine grit wet sandpaper (400 or 600) and run it between the stator/rotor. Maybe that took all of 5 minutes. Also, as per the mfg, the bellows needs to be replaced periodically (every 6 years for our model and 8-10 years for the pro). In the Winter I burp it once we're on the hard to try and get any water out of the bellows. Not sure this actually accomplishes anything though.