I have been out 4 times now in lighter conditions with the twin sails in tandem and solo modes and have been very happy with the way the boat performs. For the first time sail power has taken over from pedal power! The extra sail is just what the tandem needed to get it moving under wind power alone.
First real test in lighter conditions (windspeed 8-12 km/h) was solo, running with the wind or across it. It didn’t take me too long to get used to the extra lines. The stability of the Tandem Oasis was great -even on a reach I felt confident it would not tip. It heels over to a point and then stays there. Maximum speed reached was 8.2 km/h not pedalling (GPS). Steering was better with the fins in the down position to get the centreboard effect. When tucked up the bow would turn with the wind.
Next trip was tandem in 10 -15km/h winds. We managed all points sailing with no pedalling except on tacks. We could sail close-hauled much better with the fins in the down position. As our confidence grew our speed picked up and reaching we managed around 8km/h again. We had never experienced these speeds in light conditions before unless we were pedalling as well.
Solo into the wind is not so great though. As Roadrunner predicted with his CE calculations the second sail pushes the bow across with the wind. It is difficult to maintain a course as you move sideways as much as forward. My destination was directly into the wind and as I just didn’t seem to be getting closer I took down the sails (which worked OK on water) and pedalled directly into the wind of 15-20km/h. Interestingly pedalling I managed between 5-6km/h and combining pedalling and paddling achieved 6-7.5km/h.
Next project- a dagger board to improve solo into the wind sailing. I am thinking of getting the Adventure daggerboard and fitting it to a pipe just like the sidekick mount so that it can kick up if it hits something. Locating it just behind the front passenger should lessen sideways slip.
I have decided at this stage not to get the sidekicks as one would be dragging in the water all the time, given the heel we experience with the two sails (seen clearly in pic above). That may change though if we do capsize!!
Thanks for the great advice on this forum especially from Roadrunner, Kepnutz and Sunjammers.
Big thanks to Kev and Mick (my local Hobie dealers) for lending me the second sail. I'll be in this week to pay for it
All the Mirage Drive boats have them except the Outfitter and they are very handy at times. Here's a rather poor depiction of the concept:
