The Graupner 600bb 9.6v maybe the best solution for that boat, will give a reasonable speed getting on a reasonable plane, but run time will be its downfall, i'm estimating between 20-35 mins of run time using a larger Mha capacity battery.
It might be worth looking at using the 12v version off a LA, i expect will give up upwards of an hour depending on amp draw under load, all subject to prop size.
It may even be worth looking into the larger 700-900 size motors given the boats size, being 1m long its quite a boat, 600 will move it but i think the larger 700-900 sizes may be better for its running ability's. (not run time)
However after saying that the recommended motor setup for that boat is the Graupner 600BB 12V. but as normal some trial and error is needed with some boats to get the performance you require, prop size/pitch, motor size, battery voltage all come into play, a balanced setup is always the best so compromises sometimes have to be made.
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