I used moldable dripless packing for at least 10 years and 300 hours of running with no scoring and no crevice corrosion. I would guess that many folks do not follow the directions (hand tighten, then 1/8th of a turn, run and repeat until no drips). Boatyards
have used this stuff to remedy scored shafts from over tightened flax packing (sometimes it works if the grooves are not too bad) so I think that it has gotten a bad rap because most boatyards
do not want to send the average boater away with a system they might have to thoughtfully adjust a few times when the boat is fresh from the yard in order to get it set. You cannot just honk it down and send folks on their way like you can with the mechanical PSS Seals. It certainly is possible to create heat, grooves and crevice corrosion with any compression
sealing system if you overtighten it or do not periodically take a look at it. I repacked mine every 3 or 4 years.
The Gore stuff is not the same as other, cheaper black braided packing material according to other posters on other threads. My machinist friend who works for one of the most respected boatyards here in Maine
swears by Gore material and says that most of the local lobstermen use it (he says they honk it down and do not have a problem, but I do not recomend that) and I have been using it for about 250 hours and it seems to run very cool with no leaks
, no heat and no scoring. I used the same approach as the moldable in installing this. The folks where I buy the stuff (I buy it from are the designers and manufacturer of shaft and pump seals) are suppliers to the US Navy
. My guess is they do not use PSS shaft seals on nuclear subs--and probably dripping is not a good idea either at their speed and depth
. The guys were a bit coy about their relationship, but said that, "if it is good enough for nuclear subs, it will probably keep the water out of your boat".
After my experience as a delivery skipper
with the kind of PSS Shaftseal problems others have mentioned, I would not have one on my boat, but I understand that many people seem to like them. They are heavily marketed and pushed by the boatyards for understandable reasons. They do not want the liability to send you away from the dock
with something you might have to adjust a few times to get right.
No seal will work on an out of true shaft or fundamentally misalligned drive system.
To each his own. Maine
Sail, my fellow Mainer, operates one of the best instructional sites on the internet
for advice on boat maintenance
. He just happens, IMHO, to be wrong on this one issue.