Whitewater numbers all over the board
#1
Admirals Club 

Thread Starter

I have been keeping an eye out for a 28 or 32 whitewater for a while and continue to see fuel number and speeds all over the board. I see 28's with 250's saying they top out at 65 and then another add saying a 28 with 250's tops out at 48! I understand some variance in the operator and knowing what the boat likes but a 17 mph difference doesn't add up. I have seen similar differences in the 28 with 300's. Can anyone speak from experience and explain such a variation in reported numbers. I am looking at Whitewater for speed and ride quality but 48 WOT is obviously not as impressive as 65. Thanks for any knowledge and help.
#2
Senior Member

Back in the day we measured boat speed in something called nautical miles per hour. We rarely went over 30 knots because traveling the length of a football field every 3 seconds was considered unsafe.
Just throwing that out there since it seems like once a week someone wants to know how fast a boat runs at wot. Weight, how clean the bottom is, prop specifics, etc. are important factors... and yeah, sellers lie in listings.
Operator inattention, operator inexperience, improper lookout, machinery failure and excessive speed ranked as the top five primary contributing factors in boating accidents. Be safe.



Just throwing that out there since it seems like once a week someone wants to know how fast a boat runs at wot. Weight, how clean the bottom is, prop specifics, etc. are important factors... and yeah, sellers lie in listings.
Operator inattention, operator inexperience, improper lookout, machinery failure and excessive speed ranked as the top five primary contributing factors in boating accidents. Be safe.



#3
Senior Member

The man has a question about a boats performance and you respond with a lecture on speed kills, WTH? Although something above idle speed may have been involved in the pictured accidents, It doesn’t look like any of them were caused by speed to me. To the OP, I apologize for the sidetrack.
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#5

48 sounds like they were using knots as that equates to 55 mph which is about right. Ive got a 28 with 225 etecs and it'll run mid 50s no problem. The pitch of the props play a role in all of this.
The boat is quick when you want it to be and cuts waves when you need it to with no rattle or anything. Very solid.
The boat is quick when you want it to be and cuts waves when you need it to with no rattle or anything. Very solid.
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#6
Admirals Club 


I have twin 200 Yamaha HPDIS on my 28’ Whitewater. Flat calm, alone, in the bay and trimmed up I’ve seen 54.1 mph. Mercury Mirage 3 blade 21p wheels.
I have two friends who both have 28’ Whitewaters with twin 300 Zukes. That’s a 63 to 65 mph boat.
With twin 250s, propped correctly I’d expect to see mid to upper 50 mph.
Honestly, what you’re really after is high 30’s to low 40’s “effortless” cruising speed. Top end really isn’t that important, you want economical, stable fast cruise without taxing the engines.
I have two friends who both have 28’ Whitewaters with twin 300 Zukes. That’s a 63 to 65 mph boat.
With twin 250s, propped correctly I’d expect to see mid to upper 50 mph.
Honestly, what you’re really after is high 30’s to low 40’s “effortless” cruising speed. Top end really isn’t that important, you want economical, stable fast cruise without taxing the engines.
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#8
Admirals Club 

Thread Starter

Thanks guys. Burningdaylight your exactly right, I am looking for that faster cruise. I guess I'm figuring if the boat has the top end stated then the cruise will equate but ultimately the fast efficient cruise is what I'm looking for. Thanks again.
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#11
Senior Member


My 28 likes to cruise at about 35 mph and 4500 rpm.
Twin 200 ox66, 4 blades. It will do this in almost any type of conditions. Tops out over 50 mph.
Twin 200 ox66, 4 blades. It will do this in almost any type of conditions. Tops out over 50 mph.
Last edited by joestina; 06-27-2020 at 08:22 AM.
#12
Senior Member


I will say, though, that I don't recall seeing this huge spread in speed numbers on equally powered boats. Maybe I'm not paying attention. I can understand seeing a wide spread in numbers on 28WW's in general because they come with such a wide range of power. Twin 150s, twin 200s, twin 250s, twin 300s, single 300, etc.
A twin 300 WW should be pretty consistent across the board, no matter what props you've got. Low to mid 60's top end, 40mph cruise.
Twin 250s, knock a few mph off.
And so on.
The hull hasn't changed, literally, ever. So if you're seeing a massive discrepancy in speed between equally powered boats, then either they have props REALLY wrong, or there's something mechanically wrong somewhere.
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#14
Admirals Club 


I have owned 3 of them. First had 200 HPDI on it and it was a low 50s boat, cruised in the 30 to 40 pretty much ran square RPM to speed. That one has been repowered with Merc 225 and is a low to mid 50's boat but with improved fuel economy and cruise 30 to 40.. Second one had 200HP Suzuki 4cylinders. That one was a low 50s boat with good economy, best cruise in the 30's due to gear ratio was turning 5000 rpm to cruise at 40. My current has 300 Merc V8 and as stated is a mid 60 mph boat with props that are most efficient. Easy cruise at 40 with good economy. With prop set specifically for top speed it can be a 70 mph boat but as with anything gives up hole shot and economy at cruise.
If you look at any of my builds on here I have documented testing several sets of different props on each set up.
If you look at any of my builds on here I have documented testing several sets of different props on each set up.
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