DAMEN STAN 4207
The pond was again nice and calm, so first investigated the effect of adding weight to see how much could be added to finish the remainder of the model. With the boat floating 'as built' the bow is slightly down vs the stern. I have several 2 lb weights, so balanced one on the RIB slip. The bow rose above the waterline and the stern sank to slightly below it. Tried a further 2 lb weight and the water almost reached deck level! The ideal seems about 2 lbs, but mounted further forwards towards the centre of the model.
Left the first weight in place and started voltage runs. At the base voltage of 7.2 (the NiMH rating) performance was good. The model has a nice turn of speed and is totally predictable. increased the voltage in 1.2 volt increments to replicate NiMh voltage steps. As the voltage increased the vessel obviously goes faster, but the turning response becomes rapid and very sensitive.
Finally increased the voltage to the a maximum of 14.4 volts and decided the ideal would be 7.2 volts. This also allows all the vessel systems to work at this voltage without a voltage reducer for the bow thruster. With the cells wired in parallel, this should give over 3 hours running time.
Continued to experiment with the model for about 1 ¾ hours before a drop in performance was noticed, indicating discharging cells. During this period was able to make further assessments of the performance of the linked rudder / fin system. This system flattens turns, reducing heeling and gives a tight turning circle. if anything it is tighter than the full size vessel, so a real crew would need to hang on very tightly during max rate turns!
To my relief the only trace water was from one of the propeller shafts, the hull is sound and without leaks.
Unfortunately the weather has now turned colder and cannot do any further sailing until next Spring. At least can continue building confident in the knowledge this is the basis of a great model, one which will justify the many hours needed to finish it properly.