diamond vs wake

[5oclocksomewhere]

I know it doesn't matter on a wake boat but was just woundering if there is a difference ?

also I was checking the speedo with the gps the other day [ was still within +/- 1 mph at wake and ski speeds] opened it up and with 1/4 tank me the wife and daughter 43 was all she had , but then I got to thinking the water was between 91 and 94 I imagine this makes a big difference as the density of the water is much less , anyone else notice the same thing ? the wake also seems bigger in the warmer water ,

[MN_LSV]

Not sure about the lake temp, here in MN we are lucky to get to 80 degree water in mid summer!! We have an 03 23LSV Wakesetter which still has the diamand hull. Where we notice the big difference is when trying to surf. The wake hull makes it much easer to get a good surf wake than the diamand hull.

[mcc]

I would think that the diamond hull would have a higher top speed becasue the hull is not designed to sink as far into the water, therefore creating less drag. Just my thinking though, someone else might chime in that has a little more experience.

Edited August 12, 2009 by mcc

[srab]

I know it doesn't matter on a wake boat but was just woundering if there is a difference ?

also I was checking the speedo with the gps the other day [ was still within +/- 1 mph at wake and ski speeds] opened it up and with 1/4 tank me the wife and daughter 43 was all she had , but then I got to thinking the water was between 91 and 94 I imagine this makes a big difference as the density of the water is much less , anyone else notice the same thing ? the wake also seems bigger in the warmer water ,

Theoretically, at least, I would think that the diamond hull would get the nod. Those outer chines

pointing downwards create lift at higher speeds (which is supposed to be why the diamond hull

produces a smaller wake at slalom speeds). I'd be inclined to think that greater lift would mean

less total surface area of the hull in contact with water at a given high-end speed, thus less drag.

Also, from a physics standpoint, any actual vector force in an upward direction should decrease the

relative weight of the boat.

In the real world, though, matching the right prop with the right engine [and the intended use of

the boat] will play a far far greater role in top-end speed than any other variable.

[Swampy]

Someone else may know more about this, but I seem to recall reading that the non-diamond hulls tend to have better top speed. It had something to do with how much of the hull is actually touching the water. The diamond hull is designed to have more hull touching the water thus creating more lift but more drag.

[edgeski1]

the faster an inboard goes, the harder it tries to push the bow into the water, creating drag. so theoritecally, the wake hull should be faster as there is less lift in the rear. Take the Corvette For example, a boat designed for top speed, it does not have any turn to the outer chines whatsoever

[WakeGirl]

The SV23 on a 21' vdrive was the fastest hull as I recall. It has to do with the motor orientation as well as the hull design overcoming the tendency push the bow down as stated above. A diamond will have more lift at the rear & not want to overcome that as much, & the nose will dig harder, reducing top speed. Not sure how the newer hulls compare, but my feeling is that they're probably not as efficient as the old SV23.

[RoverOn]

I have a 23xti Sunsetter with the Diamond hull...and I can do 47+

But that may have something to do with the 365hp Hammerhead :-)

[edgeski1]

Verified w/ GPS?

[live2ski423]

'07 VTX, Wake Hull, 340 Monsoon - 49mph with no ballast. Looking to get a new prop though - with 4 full tanks + and extra 550# in each locker, Wedge and 6 on board, getting up to wakeboard speed is a long, cumbersome process... Have not decided on what prop yet, but from what I gather my top end will drop to the 40mph range once I switch to one that will do the trick when loaded

[Soon2BV]

2008 21 LSV

320 HP

ACME 537

About 700 pounds of people

10 gallons fuel (1/4 tank)

47 MPH in smooth water (not verified with GPS but plan to do that this weekend)

Very little of the hull is in the water.

(PS - sort of interesting to ride a tube, directly behind the boat, about 35 MPH, and see how the hull rides)

[5oclocksomewhere]

2007 vtx

340 monsoon

wake hull

381 prop

4800 rpm 43 mph

91-94 water

funny thing , I also notice more drag when I ski and the ski seems very slow , I have read where short line skiers half to change setups for water temp

I have had my boat do 47 mph when the water was 68 to 70 in the winter with a 537 prop , could water temp make that much of a difference

[WakeGirl]

Hmmm, well I guess it's possible. Warm water is softer, allowing the boat to sink in farther.....but I'm guessing though that it's the prop. That 381 isn't able to push it up to the redline, while the 537 can get it a lot closer. Redline on a Monsoon is between 52-5400 rpms (depending on the boat), so the closer you can get to that without actually hitting the limiter, the more dialed in that you are. The comment about drag while you're skiing would make sense too, since the 381 wouldn't be able to bite or hold speed the way that the 537 should. It sounds to me like you should be running the 537 full time.

[CRASH]

VTX

1235 43 mph

oj468 41mph

cruise speed 28-30 at 4000rpms

[mainekneeboarder]

I have some interesting info on this that surprised me!

Lake= 150 ft above sea level, about 70-75 deg on the test days ( weeks apart )

01 Sunsetter VLX, Diamond hull, monsoon engine

1 person in boat

381 prop

46.5 - 47 MPH, 5100 RPM

Same boat

1 person

537 prop, stock

45.5 - 46 MPH, 5500 RPM

Same boat

1 person

537 prop, 150cup

46.5 - 47 MPH, 5400 RPM

All speeds are on GPS perfect pass. I thought the rev limiter was 5200 RPM so I verified the tach with a Snap On digital timing light and it was dead on with the boat tach at every RPM. speeds were with in a few weeks on the same pond with about the same fuel in the boat. The 537 works very well with ether cup. I didn't notice any difference in the hole shot with more cup, but did see more top end and a drop in max RPM. The 537 holds speed much better with the boat weighted and running 21MPH, it also has much better hole shot. We notice it while boarding, but really notice it when I slalom ski. With the 381 my son pretty much goes full throttle to get me up, and it works well. The first time he did that with the 537 I got yanked out of the ski, we now don't do full throttle starts while slaloming. With 4-5 people in the boat the 537 still holds about 46MPH top speed. For us it was a win win situation!

[Slayer]

The SV23 on a 21' vdrive was the fastest hull as I recall. It has to do with the motor orientation as well as the hull design overcoming the tendency push the bow down as stated above. A diamond will have more lift at the rear & not want to overcome that as much, & the nose will dig harder, reducing top speed. Not sure how the newer hulls compare, but my feeling is that they're probably not as efficient as the old SV23.

SV23 Diamond or Wake? Is there much difference?

........they're probably not as efficient as the old SV23. How old?

[Soon2BV]

Two examples - 4000 pound boat

Density of water at 50F = 62.4 pounds / ft3

Density of water at 90F = 62.11 pounds / ft3

For the boat to float, it has to displace its weight in water.

At 50F, it would need to displace 64.1 ft3 of water.

At 90F, it would need to displace 64.4 ft3 of water.

That is about 1/2 of a percent difference.

So, everything else being the same, the warm day boat would go a little slower because it would be displacing more water.

As the boat comes up on place and moves through the water, the warm day boat would continue to be slower because it would always displace more water as it moved.

By the same calculations, if the cold day boat has just 20 more pounds in it, the displacements are the same, so the speed would be the same.

With so many other variables involved, it seems like it would be a challenge to see a performance difference due to water temp affects.

However - for a 180 pound skier, the difference between 50F water and 90F water is about 21 cubic inches of water displacement. For a high end tournament skier, where rythm and timing are critical, this might be enough difference to impact performance as they reach and stretch to make a turn.

[WakeGirl]

The SV23 on a 21' vdrive was the fastest hull as I recall. It has to do with the motor orientation as well as the hull design overcoming the tendency push the bow down as stated above. A diamond will have more lift at the rear & not want to overcome that as much, & the nose will dig harder, reducing top speed. Not sure how the newer hulls compare, but my feeling is that they're probably not as efficient as the old SV23.

SV23 Diamond or Wake? Is there much difference?

........they're probably not as efficient as the old SV23. How old?

SV23 wake. I say old because it was introduced in 1995. The last year of production for the SV23 wake hull was 2008, but from 2005-2008 it was only available on the Ride series.

[5oclocksomewhere]

now I have to put the 537 on and go test it maybe I got a thunder storm instead of a monsoon

[mainekneeboarder]

now I have to put the 537 on and go test it maybe I got a thunder storm instead of a monsoon

I would bet the air temp has more to do with your top speed then the water temp. The probably? 40 deg difference in air temp would make a big difference in engine power, and max RPM!

[nemalibu]

Sunscape 21 LSV

SV23 Diamond Hull

Monsoon 335

13.5x17.5 prop

70 degree water

1 person in the boat

3/4 full tank

No wedge

"Top speed" 47 MPH (GPS checked)

For 2 adults + 1 child the speeds and RPMs were as follows:

Engine RPM Boat Speed (MPH)

1570 7.7

2230 14.2

2230 17.7

2370 18.5

2890 26.2

3560 32.2

3950 35.5

4320 38.5

The effective prop efficiency clearly shows what happens when you get onto plane.

I plan to repeat this test with the wedge down (at leat up to 26 MPH).

[Swampy]

Two examples - 4000 pound boat

Density of water at 50F = 62.4 pounds / ft3

Density of water at 90F = 62.11 pounds / ft3

For the boat to float, it has to displace its weight in water.

At 50F, it would need to displace 64.1 ft3 of water.

At 90F, it would need to displace 64.4 ft3 of water.

That is about 1/2 of a percent difference.

So, everything else being the same, the warm day boat would go a little slower because it would be displacing more water.

As the boat comes up on place and moves through the water, the warm day boat would continue to be slower because it would always displace more water as it moved.

By the same calculations, if the cold day boat has just 20 more pounds in it, the displacements are the same, so the speed would be the same.

With so many other variables involved, it seems like it would be a challenge to see a performance difference due to water temp affects.

However - for a 180 pound skier, the difference between 50F water and 90F water is about 21 cubic inches of water displacement. For a high end tournament skier, where rythm and timing are critical, this might be enough difference to impact performance as they reach and stretch to make a turn.

Just a thought....I have no idea how to quantify it, but the density of water would also have an impact on the thrust from the prop.

[Malibudude]

The SV23 on a 21' vdrive was the fastest hull as I recall. It has to do with the motor orientation as well as the hull design overcoming the tendency push the bow down as stated above. A diamond will have more lift at the rear & not want to overcome that as much, & the nose will dig harder, reducing top speed. Not sure how the newer hulls compare, but my feeling is that they're probably not as efficient as the old SV23.

Wouldn't the outboard flightcraft be the fastest hull.

Wouldn't the prop have more bite in cooler water temps = more speed?

Who cares in the end a monsoon w/ an OJ 468 and above 30 just sucks the gas down.

[WakeGirl]

We're talking inboards here, get with the program. And footers care about top end, don't discount them. Some people do care about the capabilities of their boat & whether it's dialed in. Just because you drive yours like a great-grandpa doesn't mean that others have to.

[UWSkier]

Two examples - 4000 pound boat

Density of water at 50F = 62.4 pounds / ft3

Density of water at 90F = 62.11 pounds / ft3

For the boat to float, it has to displace its weight in water.

At 50F, it would need to displace 64.1 ft3 of water.

At 90F, it would need to displace 64.4 ft3 of water.

That is about 1/2 of a percent difference.

So, everything else being the same, the warm day boat would go a little slower because it would be displacing more water.

As the boat comes up on place and moves through the water, the warm day boat would continue to be slower because it would always displace more water as it moved.

By the same calculations, if the cold day boat has just 20 more pounds in it, the displacements are the same, so the speed would be the same.

With so many other variables involved, it seems like it would be a challenge to see a performance difference due to water temp affects.

However - for a 180 pound skier, the difference between 50F water and 90F water is about 21 cubic inches of water displacement. For a high end tournament skier, where rythm and timing are critical, this might be enough difference to impact performance as they reach and stretch to make a turn.

Just a thought....I have no idea how to quantify it, but the density of water would also have an impact on the thrust from the prop.

Yes, and on colder water, the air is usually cooler and more dense meaning your engine is running more efficiently as well. As for the tournament skier, water temperature makes a HUGE difference in how a high-end slalom ski feels. Certain models are more picky than others. For instance, my Monza would ski great in cold dense water, but in warm muddy water, it would feel terrible. An aftermarket fin has helped somewhat, but still, it's hard to compensate for the lost acceleration when the water warms up.