Before Posting, Please Read Our Posting Guidelines Below.
1. Use the full 4 digit year for everything you are asking your question about. Example: 1962, 1988, 2000, 2011 2. Include the correct name of your Whaler model. Example: Montauk 17, Montauk 170, Outrage 26, Outrage 260 3. Include the length when necessary. Example: 16, 17, 18, 20, 22 4. Do not post your email address anywhere on this site as it is already in your user profile.
I have a brand new 2016 240 Dauntless with a 300hp Mercury Verado. Unfortunately, the mid-range RPM performance is well below the published specs for this boat. It runs fine at the higher RPMs (52 mph at WOT). But at 3500RPM the Dauntless fails to maintain plane and is reaching only 10 to 12 mph when it should be 20 to 25 mph. The dealer has confirmed with BW that the engine was properly rigged with the correct propeller. The fuel system was checked and a single cylinder test revealed no problems with power output. Any thoughts on what to try next?
One last captain obvious question, was the boat bottom painted? That test data shows your boat tested with half tank of fuel, no water in tank, and only 405 lbs of people/gear. Maybe compare your typical loads to that test weight. A full tank, water, a third person, full bait well and cooler of beer could add 800 lbs, a +15% increase in the test weight. Just ideas for you.
So what size is the correct propeller? Sounds like it slipping really bad midrange then hooking up at higher speeds. Any globs of sealant or other imperfections ahead of the propeller?