as a total Newbie to the world of model subs who is about to start a scratchbuilt submarine project because I love challenges, I'd like to ask "Those Who Know" or indeed anyone who just has an opinion ,a couple of questions that so far I've been unable to find any answers to in this Forum.
1/ In general terms is there a formula to calculate the power requirement for a realistic speed of a 4-6 ft model ? Obviously I understand that much depends on the hydrodynamic 'cleaness' of any hull, it's length and displacement, or what size or wattage of motor[s] do you guys/galls use on say boats of say 4ft or 6ft length?
2/ I have seen somewhere that the ballast tank should have approx 15% extra capacity to be able to cope with water density variation due to temperature/waterborne crud/ hull mods or repairs etc. Does this approximation hold true for all systems ie cylinders/bags/ air/water?