RPM's and top speed

salcolkat

I have a 2019 Rinker 290 EX with a Volvo Penta 380 HP Motor.  The hull has been bottom painted.  The manual from Volvo Penta says i should be able to get the RPM's up to between 5600 and 6000 if not there is something wrong.  I have never been able to get the RPM's over 5100 with a top speed of 40.9 MPH.  Should i be concerned? 

JoeStang

You should definitely be seeing more rpm and speed. Here's a test with a smaller sized boat, and they got 6000rpm and 54mph.

https://www.boattest.com/oem/3211316/engines/4500018/0/

Are you raising the drive once on plane and retracting both trim tabs fully? What bottom paint did you use, I know some can affect speed as well.

salcolkat

yes i am using the auto trim.  I tried trimming it up even more but did not see any increase in RPM.  The trim tabs are all the way up.  I read the Volvo Penta test on the 380.  They did it with a 28 ft boat that weighed 6000 lbs. my 290 weighs 7700  would the extra 1700 lbs drop the rpms that much?  The bottom paint is white but i dont know what type.

salcolkat

Also the beam is 8 1/2 ft in the Volvo test and beam on my 290 is 9 ft.

PickleRick

Bottom paint type doesn't matter as far as speed is concerned although race sailboats want a hard waxed perfectly faired paint vs the ablative paint that is soft and keeps carpet and barnacle from growing on your hull as the waxed smooth hard hull is faster,   that being said if the hull is clean the bottom paint is not your issue.  If it's shag carpet then it could be your issue or at the very least hurting your cause.  Our hulls are planning hulls so one paint vs the other is a non issue and bottom paint should be chosen based on trailering, lift or slip kept. Choose what keeps your bottom clean and protected.  A trailer or lift kept boat can keep a clean naked hull for its entire life....its just more natural. Sadly once you commit to paint its best and cheapest to keep paint for life.  You can always put soft paint over hard paint but not the other way around without mucho work and effort for prep work

JasonA

Thats about topped out for that boat. I have a 2013 290 with a Merc 8.2 and can hit 5000ish max at about 39mph. I had to prop down to get those RPM's as the boat was terrible getting on plane with any type of weight on board. I bet your boat has 24p props on it, mine did. Changed to 20p and RPM went up around 800rpm and hole shot was so much better but cruise RPM jumped quite a bit at 3900rpm 29-30mph now.

salcolkat

Thanks alot guys.  

Handymans342

Prop Prop Prop

salcolkat

Thanks, appreciate everyones input.  JasonA your reply on 2013 290 was appreciated.  I think the 8.2 liter Merc is a lower revving motor than the 6.2 Volvo.  I am also considering getting a lower pitch prop, but want to make sure there isn't something else going on 1st.  I have the F5 Duoprops with a 2.14 lower unit.  I confirmed with Rinker that this is the correct prop and lower unit for the boat anyone on the forum have a 290 with the 6.2 Volvo?  Wonder what your RPM and top speed is.