When I asked Henk if I could borrow his Cetus, he asked me what I was going to do. After unfolding my plan to paddle on 12 Sept. towards our club members, who were paddling back from their instruction-camp on Vlieland, he was enthusiastic and liked to go with me.
That is nice, I thought, but now I can't paddle the Cetus. Fortunately Leo, also a Cetus owner, offers to use his Cetus.
So now we were a nice pair: both in a Cetus. 
To be able to paddle to Vlieland we must catch the tide early: launching at 7.00h. Which was a bit late really. But otherwise we had to rise even earlier than the 3.30h we had to rise today. It's in the middle of the night. How awful!
In the timing was included the finding of a suitable launching-spot, as well as a parking place for the car nearby.
That wasn't too easy and for not to loose too much time, we launched from a kind of pontoon two meters below street level.
Nevertheless our timing was perfect and we managed to launch at 7.00h sharp.
Once out of the harbour we met a condition with the wind causing slight weathercocking, combined with current coming from the same direction, from our right side, as the wind. An irregular sea was the result. I had to be alert to hold course. It could be that I had to get used to the Cetus, but I got the impression that the current played tricks with the skeg; gripping it and pushing it aside.
But after a while, when the current came from behind, the Cetus kept course perfectly, being helped by the variable skeg for weathercocking.
Paddling the Cetus from Leo made a small difference with my experience last Wednesday: while edging the kayak, the seat-lining moved a bit left-rigth. Henk and Leo both used Velcro-tape (hook and loop fasterner & klittenband) to fixate the seat liner, but obviously there was a small difference between both seats as I did not experience this "seat moving" in Henk's kayak
Paddling at ease we easily reached 10km/h; being helped by the current of course. I also tried of course paddling without using the skeg. That was not difficult while edging a bit and using a sweepstroke now and than. But all without too much effort under the conditions of today. Of course the manoeuvrability of the Cetus helps quite a lot with this.
Later when the wind increased to 5 Bft. blowing up the waves against the current, it became much easier to hold course without using the skeg and from that moment I did not use the skeg anymore. And the Cetus, she danced nicely over the sea.
Occasionally ships and ferries passed by and the waves in their wakes were a welcome intermezzo to look at the stability of the Cetus in waves. Honestly the Cetus is so very stable that that the waves did not require any extra attention from me. She just glided gracefully and in a very natural way over the waves.
We thought he Cetus to be quite fast. When paddling towards the approaching group of paddlers, the current had changed direction already and while paddling fast against wind and the 2 knot-current we were still able to reach a 5km/h. Not too bad we thought.
After turning back we paused a bit to eat something and as the other paddlers went on, we had to push hard to join them again. The current helped a bit and made us reach 13km/h.
While pushing hard with wind, waves and current from behind, it was a bit difficult to keep course as the Cetus wandered of course to both sides. I saw Henk having the same difficulty while making powerful sweepstrokes.
Having the skeg lowered to its maximum helped a bit. We still liked the Cetus and could overcome this characteristic, but I think that a beginner might have to struggle a bit under these conditions.
While paddling in the group again I compared with other kayaks and I think the speed of the Cetus is a bit above average. She is matching the good old Baidarka. Henk and me were also matching very close. Strange huh.. with two Cetus'es 
Although the deck compartment can be quite handy, it made it impossible to stretch my legs a bit farther away that the footrests because the compartment blocked the way. This also means that it is impossible to mount a foot-pump in the Cetus.
Although I was a bit stiff after 6 hours of non-stop paddling, I do not complain over comfort: the seat is comfortable, thigh-trips are excellent and the footrests are much bigger than usual. These footrests feel much better under your foot sole because they support a bigger part of your feet.
Being back in Harlingen I felt a bit embarrassed 
as we got out of our kayaks at a very nice launching spot being no more than 80 meters away from our launching spot where we had been struggling a bit this morning.
Conditions:
Wind - NE 4-5 Bft.
Wave height: approx. 20-50cm
Distance: 46 km