Sunday, September 21, 2014

New Max-Prop

So after much research we decided to go with the Max-Prop.  You can find all kinds of reasons to pick one or the other, but after we had made the decision to go with a feathering or folding prop, we came to the Max-Prop primarily based on retention of power in reverse. 
Most props surveyed out pretty equal in forward gear.  Specifically we choose:

Max-Prop - 4 Blade Easy 17" diameter by 10.5" pitch for 1.5" shaft


We tested it at full throttle in the slip for about 20 minutes (but didn't check what the RPM was running at - mistake). When we pulled out of the slip we had about 100 yards to go straight in reverse.  Immediately I noticed a big difference in handling and feel, smoother, more responsive.  Ran like a charm....in reverse.  Once into the Alameda Channel we started our journey home.  Four hours later we were back in Marina Bay and I'd say overall we felt like there was a loss of power and some vibration we hadn't felt before....what do they say about trust your instincts?  Well.... we had an engine mechanic come over and he said it felt like the prop was likely underpitched, that would explain the vibration and loss of power.  I mentioned we didn't check the RPM at the dock, not sure if this would've helped determine the issue but something to note.  Turns out he was right, after speaking to Fred at PYI (btw Fred was a pleasure to work with and this wasn't his fault, check him out at www.pyiinc.com - our transmission had been rebuilt and wasn't the standard tranny for our engine) so it turns out we had the wrong length screw for forward, we required a 20mm pitch screw vs. the 18mm we had been using.  But wait, this gets better.  When we had a diver go down to replace the screw he noticed that the forward 18mm screw was hanging out and only required his fingers to remove.  Either someone didn't put the set screws in or the set screws rattled out from our motor home!!!  Scary.  Again, trust your instincts.  What we should've done was turned around in the Alameda Channel and gone back to the yard to have someone check out the vibration.  Lesson learned and no damage done..... this time.....phew!



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