Who's running dripless shaft seals?

[captainmaniac]

I'm on the fence about dripless.... they are awesome, unless they fail... I have been thinking of going there for a few years but just can't convince myself to pull the trigger.

My understanding is that the face seal type are basically spring loaded... as long as you have the right spring tension to avoid the drips, and not so much as to burn up the graphite disk, you are good. But if the spring pops or a set screw slips... you have no seal, and that's not good!

Also the need to supply cooling water to these systems - as I understand it at displacement speeds (sailboat speeds) no water is needed. But beyond 8-10 knots (ie if you want to be on plane) you need to plumb the cooling line, and make sure the water will flow, or the seal will burn up. That gives you another set of T's, hoses, and clamps to worry about the failure of.

I don't want to dissuade anyone from going to dripless... just make sure you understand what you are getting in to and recognize that it does still require some observation and maintenance. And understand that it is a choice, not a miracle cure. Far too many sales guys will just tell you 'Install these and you will never have a drop of water in the bilge, and never have to worry about it again!'. Can't speak for the tricabins (but think I can), but if you have an F32 or F36 without full cockpit enclosure, you get some water in the bilge every time it rains because the cockpit flooring is simply not watertight! You are gonna get water. Who cares if it comes from the shaft? Control it - yes... but you have little to gain from trying to eliminate it IMO.

Whichever way you go, make sure things aren't running too hot. Get an IR thermometer and check the stuffing box from time to time to make sure temps are not out of line. If you are dry but running at 150F+, you are probably doing damage.

[yorklyn]

Very good point Harris!

[RWS]

Very good point Harris!

Thank you.

It's kind of like....

When was the last time you did a "tune up" on your car?

Points, condenser, plugs, rotor, cap . . . . .

If the technology is available, reasonably priced, and above all RELIABLE, does it not make sense to use it ?

Save time and increase reliability?

We all even gave up on tire tubes. kingpins and knee action shock absorbers awhile back, too.

RWS

[larryeddington]

[quote="captainmaniac"]" My understanding is that the face seal type are basically spring loaded... as long as you have the right spring tension to avoid the drips, and not so much as to burn up the graphite disk, you are good. But if the spring pops or a set screw slips... you have no seal, and that's not good!

Also the need to supply cooling water to these systems - as I understand it at displacement speeds (sailboat speeds) no water is needed. But beyond 8-10 knots (ie if you want to be on plane) you need to plumb the cooling line, and make sure the water will flow, or the seal will burn up. That gives you another set of T's, hoses, and clamps to worry about the failure of. "

The "spring tension" is provided by the neoprene bellows and instructions guide you how to set it so as to be just right. The water hookup is quite simple as the device has a barb on it and you just need a barb for supply, I put a T on the inboard bypass hose that goes from tstat housing to exhaust hose. Seems to work perfectly. If the bellows is set correctly there should not be a worry about temperature, it is not a lot of pressure.

I like mine but am going to put the thermometer on it just out of curiosity.

[Paul]

When I added the LasDrop bellow type shaft seal, it was at the same time that I replaced the shaft and upgraded to a taper lock shaft coupler at the transmission. The new coupler and shaft seal assembly took up all of the shaft between the trans and the stern tube and then some. So what I had to do was compress the bellow about a 1/4" more than what was specked out on the instructions in order to fit every thing in. The nice thing about the bellow is that the extra 1/4" didn't seem to affect the force applied much if at all. So with the way this installation went, when you look down in my bilge you can't see the shaft, just the seal and coupler. 14 years now and still a dry bilge.

[yorklyn]

wow Paul, 14 years! sounds like money well spent!

[yorklyn]

How about these? looks like I may be able to get a set for $300 total.

"The Friction Ring assembly is mounted with a ridgid connection hose and uses a carbon graphite sealing surface all encased by a durable copolymer housing. Cutlass bearing ensures proper alignment to the shaft even if the shaft itself is not aligned. The clamp pressure assembly secures the assembly around the shaft preventing galling or damage to the shaft that can occur with set screws. The 316 stainless steel ring floats on the ball bearing drive system maintaining complete contact with the carbon graphite seal surface. Seal ring features two rubber/fiber U-cup seals that rotate with the shaft and never wears out. Hose barbs are constructed of solid brass and are coated to prevent corrosion. Hose clamps are manufactured of 316 stainless steel with indentations rather than perforations providing twice the tensile strength and eliminating friction as in regular clamps. Two hose clamps provide for each connection point. Virtually no metal to metal contact eliminates the risk of electrolysis."

http://www.lasdrop.com/gen_2.html

[RWS]

My shafts are "exposed"

I put a piece of red vinyl tape on my shaft close to the coupler.

That way if it was to ever slip or move, it would be easily noticed.

Nine years and no problems (yet)

The only leaks I get are from my hatches (soon to be rectified)

RWS