03 31’ jupiter twin 300’s prop size
07-01-2019, 06:31 PM
#1
Admirals Club 
Thread Starter
Join Date: Jun 2016
Posts: 40
03 31’ jupiter twin 300’s prop size
Hey guys. My 31 jupiter has twin 300’s with 16x23 wheels on it right now which i know is too big. The motors are also on the lowest mark on the armstrong bracket.
With about 175 gallons and only myself and one passenger I'm hitting 5250 rpms at 42 knots and approx. 60% trim at WOT.
The boat will usually have a 4 man crew with gear, ice, and 250-300 gallons of fuel for the long haul trips. I do not want to over stress the motors and it is definitely sluggish out of the hole.
So, should i go for 21.5’s or try even smaller?
thanks in advance, CJ
With about 175 gallons and only myself and one passenger I'm hitting 5250 rpms at 42 knots and approx. 60% trim at WOT.
The boat will usually have a 4 man crew with gear, ice, and 250-300 gallons of fuel for the long haul trips. I do not want to over stress the motors and it is definitely sluggish out of the hole.
So, should i go for 21.5’s or try even smaller?
thanks in advance, CJ
07-02-2019, 04:21 AM
#2
Senior Member
THT sponsorJoin Date: Jan 2007
Location: Pompano Beach, FL
Posts: 1,949
Those props are way to big, I would drop down to 20's, this will get you closer to the 6000 rpm range where you want to be. You should be able to come up a hole or two as well with motor height from the sounds of. When up and running is the cavitation plate buried under water? Can you see it at all?
07-02-2019, 05:00 AM
#3
Admirals Club
Thread Starter
Join Date: Jun 2016
Posts: 40
Thanks for the quick response. I figured they are too big. I haven’t had the chance to see the cavitation plate yet. My guess is that they can also come up a hole. I don’t want to worry about getting blow out in rough seas though. Do you think the 21.5 is still too big?
