Hmm...
There are a couple of factors here.
Drag increases exponentially with speed so, starting from the same speed, an increase in effort will give a greater difference in speed on a faster boat (i.e. that has less drag) than on a slower boat.
But you could extrapolate back from the faster boat to the slower boat to get an approximation...
So let's see. In his article, Nick says that he put the same effort into paddling each boat (as measured by HR). He paddled the fastest boat, the V10 2g, at 6.8mph - or 11kph in my language.
On flat water I'd expect a paddler like Nick ("expert") to average 12-12.5kph 7.5mph on a fast ski on flat water.
So call it 1.5kph/1mph faster than what he did on his time trial described in his article.
Because the drag with the slower boat will increase more rapidly, you won't get the same increase in speed. Call it .7 mph faster on the slow boat...
So I'd guess that Nick, putting effort in, could probably maintain 6.4mph on the V5. There's your "expert" speed.
Your "proficient" would be, hmm... around 5.5mph...
But wind, depth of water, waves, distance will all affect that. I'd say you're not doing too badly at all!
It'll soon be time to trade your V5 in and get the V8 Pro!
Rob
Currently Epic V10 Elite, Epic V10 Double.
Previously: Swordfish S, Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...