PilotFish Mk.III - If at first (and second) you don't succeed...

by Web FishMar 24, 2015 @ 08:49pm

If at first you don't succeed, try, try, try again.

Another year - another PilotFish design. Since this is the second major reboot of the project, we should be getting very good at learning from our failures :)

What did we learn from Mk.II? Here is the short list:

  • Structural integrity is both paramount and difficult to achieve. Actually, this statement is only partially true. We can make things reasonably strong, but in the process they get quite heavy. Reliable mounting points on thin-walled structures are a challenge;
  • Weight is important. Really important. Mk.II floats got extended vertically twice to compensate for the ever growing total weight;
  • Free board is overrated. Well, not really. But in our case it doesn't seem to make a big difference - it only increases windage with little effect on everything else;
  • Ease of build. Spending 4 man-years building something that has a limited chance of survival doesn't sound fun. And now that the MicroTransat challenge is open to powered vessels, this is becoming important.

 

So what's next for Project PilotFish?

 

 A simpler, lighter, stronger and hopefully better Mk.III design:

 

 

As we all know, third time's the charm. Apart from that, this is what Mk.III has going for it:

  • Simpler tubular floats made from multi-layer plastic stock - light and strong with reasonable drag;
  • No need for risers and cross-members in the deck structure - light and simple;
  • Super-strong mounting points while still allowing full disassembly for maintenance / repairs;
  • Very low vertical profile driving down windage factor;
  • Natural compartmentalization of float volume;

And a few challenges which will need to be addressed during the build process:

  • Limited displacement / floatation. Adhering to the design weight budget is paramount;
  • Switching to a smaller size / lower power rating solar panels will put extra stress on the power budget;
  • Watertight mounting for rear and aft float sections;
  • Mounting / orientation of the GPS and satcom antennas with floats having limited freeboard;

 

Let the journey begin...