Prop question - 1989 Sea Ray 300DA

[QC]

Re: Prop question - 1989 Sea Ray 300DA

I usually tuck the drives all the way down, bottom out the trim tabs, throttle up to about 3/4+, get her up, reset tabs all the way up, trim outdrives, throttle back to 3,000 for a 30 knot cruise.

This is pretty darn good. Since the throttle up situation only happens a couple of times a day, I am confused why improvement here is so important. Also, I would never bring my tabs "all the way up" on a cruiser.

I currently need to run minimum about 2,7000 RPM at 25-27 knot cruise otherwise she falls off plane. If I deploy trim tabs and\or trim down the IOs I can hold plane at lower speeds (but with much more "drag").

Same comment about the tabs. If you lift them and she starts to fall off plane, that is significantly more "drag" than the tabs create holding her up . . . If the same throttle position results in a faster speed, it does not matter how you do it, you are more efficient overall. Just something to think about. Some guys never lift their tabs because their boats are so underpowered it is the only way that they can maintain a plane. This is not bad, it is just the only way to do it with an underpowered boat. If she can plane with more tab and less throttle all is good. And the flow meter would agree.

 

[Grand Larsony]

Re: Prop question - 1989 Sea Ray 300DA

Sorry - no pictures until the boat comes out of storage in about a month.

The current props are Michigan Wheel 3-blade aluminum 14x19.

Just remembered I have two spares for the Sea Ray (also have minor damage), and I have to repair the spare on our Donzi... so a trip to the prop-fixer-man is coming up.

The plan is to fix the Donzi prop ($60?), fix two of my existing (4) 14x19's to use as spares, and purchase new 4-blade 14.5x17's for primary props if that's still a good recommendation.

Thanks guys !!!

 

[hwsiii]

Re: Prop question - 1989 Sea Ray 300DA

Grand, when you pickup the props to bring to the prop shop then you can take some pictures.



H

 

[Grand Larsony]

Re: Prop question - 1989 Sea Ray 300DA

Just closing out the post -- am simply going to recondition the two spares (19" pitch, just like the two that are currently mounted). Will swap them out and use the current ones as spares. Used the extra cash for other boating stuff instead. May be next year.