Wednesday, August 20

Nice Shaft

By Michael Argyelan

Get your head out of the gutter. We’re talking about prop shafts here. PSS (Packless Sealing System) Shaft Seals have been keeping bilges dry for years. If you are getting water into your bilge and/or engine compartment from your stuffing box and would like to keep things nice and dry, you should look into changing out your standard stuffing box to a drip-less shaft seal by PYI.

I’ve talked to so many boaters who complain about replacing the packing on their stuffing box, adjusting it every year, or having issues keeping the bilge dry when they run the engine for a long time. The PSS system is the solution. No more adjusting. No more packing. No more water.

This is not a new product by any means. Many of our customers already have these installed and seem to love them. They’re on racing boats, day cruisers, power boats, commercial boats, etc. Why not yours?

From the manufacturer, “The PSS Shaft Seal is a mechanical face seal that is created between the flat surfaces of the rotating stainless steel rotor and the stationary carbon flange. The stationary carbon flange is attached to the vessels stern tube with hose clamps and the carbon flange is attached to the front side of the bellows with hose clamps. The stainless steel rotor is fit on the shaft in front of the carbon flange. The stainless steel rotor is used to compress the bellows before the collar is secured to the shaft with set-screws. This compression (pre-load) maintains contact between the faces and allows the PSS to compensate for the thrust from the propeller. The carbon flange is bored larger than the shaft diameter allowing it to “float” around the shaft and thus compensate for most misalignment and vibration problems. The stainless steel collar is sealed to the shaft by two o-rings that are recessed into the bore of the collar. These o-rings rotate with the shaft and stainless steel rotor and do not experience wear during operation.”

If you’re interested in the PSS Shaft Seal system, there are a few things to keep in mind. The unit must be installed with the boat out of the water. Depending on the shaft length and room between the transmission and the stern tube, you may need to pull the prop and/or drop the rudder to extend the shaft out far enough to get the unit in. To properly size and price a drip-less shaft seal you will need the diameter of the shaft and the diameter of the shaft tube.

These units will work on shafts from ¾” up to 6” so it’s likely that they will work on 90% of the pleasure boats in the Chicago area. There are some boats where there is not enough room for the PSS seal to fit, either lengthwise along the shaft or between the stern tube and the hull. Also, some shafts need the support of the packing to keep from whipping excessively. If you are interested in a drip-less shaft seal and you have any questions regarding the fit for your boat, contact us for a consultation.

Have questions? Want more information? Would you like a quote to have one installed over the winter lay-up season? Contact Andrew Spaulding at and he will get the ball rolling. 

No comments: