Wrong prop on a Maxum 1800SR3??

[Wakeboarder Tom]

Hi Guys<br />Hope someone more knowledgable than me can help!<br />I have just bought a new Maxum 1800 SR3 with a 190hp 4.3l mercruiser. The prop fitted is a standard three bladed 14.25 x 23p which according to the dealer is the correct pitch prop.<br />When accelerating with a skiier or boarder behind, the boat takes an age to get on the plane - a good 10-15 seconds. I need the boat to sit at a constant 20mph, but it keeps dropping off the plane at this speed/rpm when cornering or any increase in load from the skiier.<br />Our local boat dealer says that this problem has arisen on 2 other 1800SR3's he has come across and has fitted a 21P high five to them.<br />I am not bothered about top end speed - the WOT revs are a bit low at about 4500 (engine not run in yet so I don't want to keep her at WOT to see if it picks up) Limit is 4500-4800 rpm.<br />Question is - have I got the wrong pitch prop and what prop do I need to increase the initial accelaration to 20mph and then keep it there?<br /><br />Thanks Guys<br /><br />Oh - I should add that it cavitates on the corners if the trim is anything other than totally down - which I don't want as it wipes out a pile of wake for me to jump!

 

[walleyehed]

Re: Wrong prop on a Maxum 1800SR3??

Welcome aboard!!<br />It's usually best to shoot for the top of or just slightly above the max RPM when using the rig for that type of water sports...<br />I can see why the dealer says a high-5 will "fix" your problem, and that may be fine for what you are doing.<br />The stock prop may not have enough cup/bite to hold at the speed you need for boarding..atleast thats what it sound like.<br />Also, for what you are doing, a set of smart-tabs is a wise investment because it keeps an even attitude at all speeds, allows more room for adjustment of speed/RPM without falling off plane..they're perfect for what you're doing. If you went with Tabs, you could stay with a 3-blade and keep your max speed, but it's still best to be a bit higher in the RPM range. A good SS in a 21P would likely put you a bit higher RPM-wise, and a quality SS won't cost you in speed when dropping down from aluminum.

 

[Wakeboarder Tom]

Re: Wrong prop on a Maxum 1800SR3??

Thanks for the reply Kenny. A quick query though - will the trim tabs decrease the wake off the back of the boat as they pull the back end further out of the water?<br /><br />Also, how much is the 21P likely to increase the revs by?<br /><br />What is the "hole shot" that the high five reports to increase?<br /><br />Cheers

 

[walleyehed]

Re: Wrong prop on a Maxum 1800SR3??

Hole-shot is basically the time it takes to get fully on plane...the high-5 would decrease that time, so would the tabs.<br />With Tabs, the boat moves freely at about any speed, although a heavy boat will still produce a good wake, you just won't be fighting it falling off plane.

 

[studlymandingo]

Re: Wrong prop on a Maxum 1800SR3??

My trim tabs actually made my wake a little bigger by kicking some of the water back further which in turn, mixes with the kick from the motor. I can get some good air behind my center console!

 

[Wakeboarder Tom]

Re: Wrong prop on a Maxum 1800SR3??

Thanks for the advice guys. I can only afford to fit either a high five or trim tabs, but not both! Which would be the better option to start with, the prop or the tabs?<br />Cheers<br />Tom

 

[tommays]

Re: Wrong prop on a Maxum 1800SR3??

You will never hold good wake board speeds with out tabs unless you can move you hand REALLy fast <br /><br />If money is a problem go with a ALU prop in the short term and get the tabs<br /><br />20 MPH is pretty fast for most riders any way ? <br /><br />

<br /><br /><br />tommays

 

[Wakeboarder Tom]

Re: Wrong prop on a Maxum 1800SR3??

Nice SHot!<br />What boat are you being towed with?<br />CHeers for the advice about the tabs - I will have to try and get some over here - i suspect that a few calls across the pond will be needed as the dealers over here seem to add on a bit more than just import duty and tax! (usally double the figure in $ and you get the value in £!

 

[tommays]

Re: Wrong prop on a Maxum 1800SR3??

ITs a 1976 Correct Craft with a mid engine were a SKI boat should have it <br /><br />Ya sure dont have to worry about holding speed<br /><br /><br />tommays

 

[Wakeboarder Tom]

Re: Wrong prop on a Maxum 1800SR3??

Question for Kenny - <br />I have been looking on the interweb - I have found a company called Nautilus (SP?) who supply automatic adjusting tabs by gas rams with no hardwiring or trim adjustment - they adjust purely by the pressure in the gas ram - 80lbs per ram. Are these the tabs you were thinking of?<br /><br />Cheers

 

[walleyehed]

Re: Wrong prop on a Maxum 1800SR3??

Not only is that what I'm talking of...it's what I have installed on my boat... look right here.....click on link below.<br /> http://www.iboats.com/mall/index.cg...rd&keywords=smart+tabs&submit.x=26&submit.y=5

 

[Wakeboarder Tom]

Re: Wrong prop on a Maxum 1800SR3??

Thanks<br />I have ordered a set off ebay! Unfortunately iboats can't ship to the UK!<br />21p high five has been ordered as well<br /><br />Thanks for all the advice Kenny, Studleymandingo and Tommays!

 

[jcl4y]

Re: Wrong prop on a Maxum 1800SR3??

What were the results?

I have same boat, engine, prop and problem.

Have been considering 21P High Five and/or Smart Tabs, worried that tabs would reduce the wake (and nervous about drilling holes in my nice new hull).

Woulkd be extemely useful to hear from someone thas has tried one of both.