I picked up a couple of Drive Well Seals recently and am pretty pleased at the the difference. They effectively eliminate the serge that pulses into the drivewell area and redirect some of that misspent energy for a small speed gain.
Here's what it looks like in the well:
It attaches to your Drive with a couple of zip ties (included):
Tightened nice and tight and trimmed, it looks like this:
Here's the Seal in action in the Adventure:
And here is is in the Oasis:
As you can see, it effectively nullifies any pulse.
For measuring speed differences, I used the Adventure with my wife's ST fins and recorded two benchmarks during each of four timed sessions at the local lake (2 without seal and 2 with seal). For my 2.4 mile component, the seal averaged .14 MPH faster in mostly calm water; for the one hour run, the sealed unit averaged .08 MPH faster (two directions to minimize any breeze or current influences). My slowest time with the sealed unit was .07 MPH faster than my fastest comparable time with the non-sealed Drive. It's not a great speed advantage, but it comes without any additional effort, so I like it! For 10 bucks, it makes a nice improvement, especially in the Adventure where serge otherwise pulses up to the hatch area.
