290 Sundancer Prop Question

Seayall

New Member
Mar 2, 2009
5
Southeast Michigan
Boat Info
1999 290 Sundancer
1996 Ebbtide RX19
Engines
Mercury 5.0 Twins
Mazda Rotory
I have a 1999 290 Sundancer with twin 5.0 engines with Alpha One outdrives. My props have three blades at 19 degrees.
Here is my question, I have a heck of a time getting out of the hole and up on plane. Once I do the boat runs fine. I am looking for some ideas on how to improve getting up on plane. I have been think about going to four blade props. I would appreciate any feedback.

Thanks - Seayall
 
I think you are judging this boat's performance against past performance of other boats you have owned, or ridden on. The 290 is a 10,200 lb. boat, dry, and probably 12,000 lbs. with fuel, water, passengers, and junk. That's a lot of weight, and more than any other boat this size that I know of. I owned a '98 290 DA with the 260 HP 5.7s, and it was the same way.

I don't think there is a cure-all solution here; anything you change with cause a compromise elsewhere. Quality boats are heavy....
 
Your hole shot will improve slightly with a switch to same diameter, but 18 pitch in a 4 blade. Top speed will be slightly less with the 4 blades.
 
Different props probly won't help a bit. You may get better on plane time with larger trim tabs...but the engine power is the engine power. As said earlier, thats a big-heavy boat.
 
What is your WOT, trimmed out?

Do you use your tabs?

What's the condition of your hull bottom?

Are the props in great shape?
 
Maybe you guys are right, I dont want to burn money fixing an issue that can't be fixed. It has crossed my mind that it is just a big heavy boat and I have to deal with it.

Thanks for the feedback.
 
What is your WOT, trimmed out?

Do you use your tabs?

What's the condition of your hull bottom?

Are the props in great shape?

If you answer these questions there may be some way to improve what you have without spending a fortune. :huh:

My guess is there probably is something that'll help. My 290 planes quickly.
 
What is your WOT, trimmed out?

Do you use your tabs?

What's the condition of your hull bottom?

Are the props in great shape?

OK my bad..what is WOT?

Yes on trim tabs
Hull had bottom paint, boat in Lake Erie
Props are in good shape
 
I have another question.
Your signature info states "Engine(s): Mercury 5.0 Twins Mazda Rotory"
What's the Mazda rotory? That has nothing to do with the boat engines does it?
 
There's a ton of good advice listed above:

What are your hole shot expectations?
What are you comparing it to?
Are you using tabs? (correctly?)
Condition of the bottom?
Condition of the props?
etc.

I will respectfully disagree with the comment about the lack of impact a potential switch to a 4 blade props would have. While I don't claim to be a prop expert, it has bee my personal experience that there is a difference in the performance. I get up on plane quicker with my 4blade 14.5x18 props, which is a good thing, but I have a slightly lower top end speed (not important to me). Whether this "prop swap" will meet your expectations...don't know. The fortunate thing for you is that I believe you said you have Alpha I drives, correct. You could easily do your own research as a set of counter rotating props for this out-drive will cost you less than $300 (for both) if you shop around. I just bought two Quicksilver Aluminum counter rotating props with hub kits for about $280.

Best of luck. :smt001
 
I have another question.
Your signature info states "Engine(s): Mercury 5.0 Twins Mazda Rotory"
What's the Mazda rotory? That has nothing to do with the boat engines does it?

My Mazda rotory engine is in my other boat, a 19' Ebbtide RX19.
 
WOT is an abbreviation for "Wide Open Throttle". The question revolves around what your RPM and top speed numbers are respectively with your current set up. If you are at the top of your recommended RPM range (4800 RPM) with your current set up...you should stay with what you have (19" pitch) or possibly consider a 4 blade prop with a pitch of 18". You would also be able to stay on plane at a lower speed due to the increased efficiency of the 4 blade prop.

If however your WOT RPM is around 4400~4600 then you could switch to a pair of 17" pitch 3 blade props and help your "hole shot" problem a bunch.:thumbsup:

Good Luck

John F
 
You shouldn't need your tabs to get on plane. The drives all the way down is the best place to start. I'm sure you do this anyways.
Props...
2 blade - Mainly folding props for snailboats.
3 blade - Best top speed and a good cruising prop.
4 blade - Boat feels 'tighter' and will ride a bit higher in the stern.
5 blade - Mainly watersport and low speed. Bites hard but it's slower.
The differences are more noticable on smaller faster boats but the traits are there regardless.
As opposed to the 3 blade, a 4 will plane a little faster and will reduce the tendency of porpoising if that's a problem. It will be a little slower though.
These are decent guidelines but in the real world there's variables so the best way to choose a prop is to experiment.
Cheers!
 
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I have a question- has anybody tried the various "wing" products that can be added to the cavitation plate to help these heavy rear ended boats with outdrives get on plane quicker
I got my '88 300 DA out last weekend for the first time and it too was slow to plane.

I have another boat that is a heavy 27 ft sportfisher with twin 200 outboards and trim tabs and it was slow to plane. I did add the wing devices (I don't remember which brand) and now it pops up quickly and easily.

What is the consensus here about using the cav plate wings on Sea Rays? Good, bad or ugly?
 
I too thought about the "wings" and I asked the service guy at my local Sea Ray dealer and he said that he has never seen anyone put thoses on larger boats. That was my first thought to try before getting different props. I would also be interested to hear from anyone that has tried these devices on a twin engine boat.
 
My first thought is that it would have a very minimal effect. They create lift like an airplane wing. They can only create so much lift - let's say we refer to this force in a certain amount of pounds. I have no clue what the actual number would be - but let's just say it's "X" lbs. Now, X lbs of lift helping an 18' runabout would certainly help. However, that same wing on a 30' cruiser is not going to help nearly as much as the wing is still providing the same amount of force, but the boat is now much heavier.

I could be totally wrong on my line of thinking - if someone can provide some factual info on this, I would be curious to hear it.

Not saying they aren't, but I, also, have never seen or heard of them being used on cruisers.

I've never thought about them in terms of being similar to a trim tab before. Gotta think some more about that one.
 
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I think that their effect is more related to the fact that when the engine/outdrive is tucked all the way in, then that wing is actually angled up so it's effect is more like an airelon (spelling?... ok flaps) than a wing lift effect. Pilots???....
 
When the drive is all the way down there's two things. One, the prop thrust is directed downward... thus lifting the stern and two... the approaching water washes in to the cavitation plate creating a small amount of lift initially but as the speed increases, so does the pressure against the cavitation plate. On plane it will create so much lift it will push the bow in to the water and cause it to plow. We compensate by trimming the drive(s) up to level the boat causing less friction. A boat that has trouble planing will definitely benefit from a larger cavitation plate and / or bigger trim tabs.
It's the opposite at higher speeds; we can trim the drives up to raise the bow out of the water to further reduce drag... of which the cavitation plate is pretty well out of the water... so they won't help raising the bow.
 
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I think I'll bite and try some on my boat but it will be a few weeks before I can get back to it, install and test drive. I will post the results for everybody when I do this.
 

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