<Bill wrote: I've installed a pair of Evolution shafts on my current project yet to be launched and would appreciate any feedback or user experience you'd care to share, email me offlist if you wish.> We have nothing but good to say about the whole system and all the issues that it solves. 1. No stuffing box so no water in the boat. 2. No cutlass bearing so no worries about wear or a line wrapping and spinning it. 3. Almost frictionless. We can turn our 38" prop in the water just by turning the shaft by hand. 4. Because all the torque and thrust are handled by the sealed tube and bearing assemblies the engine is free to float on soft mounts which reduced vibration to the hull 5. The Spicer u-joints and sliding jackshaft are 3 times bigger than they need to be for our torque load. Good safety margin for when you hit that log or other immovable object underway. 6. The shaft tube and housing is filled with EP90 oil which is under 4-8 lbs of pressure. This keeps the bearings bathed in oil and also is an instant notification if you were to lose a seal, etc, as the pressure would drop. We put it up at 5 lbs a year ago and it's at 4.5 as I look at the gauge. Pretty tight system, IMHO. 7. Zero alignment is required as we have +/- 30 degree vertical & horizontal that the u joints can handle plus we can have 4" of fore and aft movement. Our DD 6/71 can be moved easily on the mounts by hand. No vibration is transmitted to the hull or structure. If you need to replace you old shaft tube, stuffing box cutlass bearing or shaft it makes sense to consider installing one. Most likely a 50% premium over replacing the old components. If you are rebuilding/repowering a boat and need to re-shaft as part of that process it's a no brainer. No need to bore sight the new tube as the alignment by a string is good enough. It makes the installation time drop dramatically. All it all it is a big ship shaft system scaled down to small boats. Very efficient and very effective, IMHO. BTW, I have no involvement with them other than I know where there shop is in Maine ;-) As always YMMV..... Dave & Nancy Swan Song Roughwater 58