I've put a deposit on a 19" four blade Variprop, but it's not going on the shaft until next winter. I just wrote a message to a friend outlining what I've bought and why, which I'll paste here with the hope it helps.
My friend asked if I was intended to install the PSS shaft seal device instead of a traditional bronze stuffing box, to which I replied:
Yes, that is the "bellows" style of shaft seal. I will be installing it with this coupling system:
The advantages of all these expensive parts are (moving forward up the shaft from the prop)
1) more torque and better power band utilization with the Variprop 4 blade;
2) speed gain under sail with the feathering blades.
3) ability to change the prop pitch underwater with an Allen key.
4) shaft seal means a dry bilge.
5) thrust bearing/universal joint coupling allows isolation of transmission components from shaft play, reducing engine wear.
6) reduction of noise and vibration to hull
7) soft mounts further reduce vibration, allowing engine to "float" relative to shaft.
8) engine can be run at a heel without fear of sheering effects. Engine is still subject to oil distribution problems at heel, but you won't wear the tranny out as would happen with a hard coupling.
9) Alignment problems no longer a factor.
I've examined the various options, and we feel this gives us a quieter and more reliable drivetrain that makes full use of the shaft output while gaining us the real advantage in drag reduction available by using a feathering prop.
I'm seriously considering a VariProp for my boat too - assume that you have checked the VariProp web site, so I won't repeat the info. The U.S. distributor (from Thomaston, Maine) is going to be present at the Maine Boatbuilder's Show in Portland, Maine this weekend (16,17,18 March), offering "boat show discount pricing". Might be worth your while if the snowstorm isn't too bad, and you are in New England? Don't know how much the "discount" is, but with the price of these things (the biggest drawback), every little bit helps!
I got 10% off, I think. I ran the template yesterday and I have plenty of clearance, so I've ordered a 19" x 15" four-bladed Variprop. I know the Canadian distributor allowed me to secure the current price and discount with a deposit.
Thanks very much for your previous post on this topic, and for the info regarding the "discount" and payment options. Congrats on the purchase of your new prop - hope it works really well for you. We're still hoping to hook up with the VariProp rep at the Portland, Maine show - our weather has been pretty nasty in the last 24 Hrs, but it is raining now. Maybe we'll attend on Sunday. Happy sailing!