I don't want to be a wet blanket, (eg; spoil the fun), but it's difficult to see how a mix of different types of water craft could keep up with each other!
A high speed motor boat is going to leave a becalmed sailing boat stranded...!!!
The only way it would work is for all the participants to agree to use similar craft for each tour....
...all motor launches, or all sailing boats, or all canoes, etc...
...so that they are all capable of travelling at similar speeds!
Otherwise it's like organising a tour using a mix of Flexwings and F-16 Fighter planes....it's not going to work...

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LOL...!
It's an interesting idea though, for the very few slow and easy, laid-back members in Sim V....
...and apart from me, there aren't too many of them here!..trust me...!
LOL...!
Paul...Splicing the mainbrace...Avast there, my hearties!..

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.