Planing issue
 

Just filled the gas tank (on the water) and I couldn't get the boat to plane out with 4 adults (2 men, 2 women) on board with a full tank. It was fairly windy, 95 Davanti with a 305. Prop is original 3 blade prop, unsure on pitch but it is factory. We moved the girls to in between the front seats and it planed out right away. I figured it was probably a weight issue, i filled from half tank to full tank. Didnt have an issue with a half tank. Would a 4 blade prop solve this issue?

Re: Planing issue
 

Possibly but we do need to know what prop (dia x pitch) is on there now. The other thing that will help even more is a set of Smart Tabs. If you do a site search (top right corner of your screen) you will find numerous threads discussing their benefits.

Other than those two items the only other thing i can think of is stop eating all those Big Macs.... ;)

Re: Planing issue
 

x2 on the Smart Tabs - you won't believe the improvement and installation is super easy. I think they are probably one of the best investment you can make for your boat.

Nick

Re: Planing issue
 

Thanks I will take a look at the smart tabs...and Mikey is probably the newly offered Poutine at the local ball park thats doing it!

Once I get the boat out of the water next week, I will post the Prop info.

Re: Planing issue
 

:rolling_laugh::rolling_laugh:

Re: Planing issue
 

Smart tabs!!! Put them on my Talari and took it out last weekend...man what a difference!!!

Re: Planing issue
 

soooo I pulled her out of the water today annnnnd BAM! bent prop. We keep it in the water a majority of the time, and where we keep it is pretty shallow bc of the power authority sucking down water levels at night.....Could I use the trailer button as I approach to get the outdrive up and away from the bottom? Also what is factory pitch diameter for my boat....95 Davanti 225 with a 305/Alpha....

Re: Planing issue
 

heres some pics....also note the broken "fin" under the prop....

Re: Planing issue
 

Yes unless you prefer to keep replacing props.

Again, what prop (dia x pitch) is on the boat now? "factory pitch" depended on where the boat was being delivered to as higher elevations required different pitch props.

Re: Planing issue
 

"Skeg"

Re: Planing issue
 

Everytime i hear 'fin' i think of those stupid hydrofoil thingys. :yes_grin:

And you will definitely either have to have the skeg welded or install a skeg guard. But then i'm not sure there is enough left of the skeg to install a guard..... :shakehead:

Re: Planing issue
 

Mikey if you carry on like this you'll end up needing help! http://www.cosgan.de/images/midi/muede/p040.gif

Re: Planing issue
 

Like a good single malt scotch fed intravenously?

Re: Planing issue
 

As much as I love replacing props, I would rather not.....Im not sure of the pitch diameter, no stamping on it anywhere. it is an aluminum prop and thats about all I know....

Re: Planing issue
 

Thats why I said that Mikey....Figured its pretty early so you might as well get your blood pressure up! along with your caffiene levels...

Re: Planing issue
 

It will be stamped somewhere and that is usually on the front of the prop hub.

Re: Planing issue
 

:yes_grin:

Re: Planing issue
 

So I found the stamping....pretty beat up but it is a 19 inch pitch....replacing with an aluminum prop is the cheapest, but not sure if its the most cost effective....thoughts?

Re: Planing issue
 

Aluminum is the best all around choice, particularly if you have a habit of bumping into things underwater with them. SS provides only a marginal increase in performance and generally at twice or more the cost of an aluminum prop. Composite props are good for spares only and should be avoided for the most part. As for your boat/motor, the 3 blade aluminum 19" was the most common prop used. You could switch to a 20" - 4 blade along with the Smart Tabs and that should considerably help your low end 'grunt' and mid-range performance.

Re: Planing issue
 

Thanks Mikey! Are the props on iboats decent? I found a 4 blade Michigan wheel vortex for $148....

Re: Planing issue
 

That's where i bought mine from. :)

Re: Planing issue
 

Ended up going with a michigan wheel cupped 20" pitch 4 blade from I boats. Found a local reputable welder that is going to fab up the skeg for a reasonable price. Should be back in the water by the beginning of the week....

Re: Planing issue
 

So a local welder with marine experience fabricated the rest of my skeg, only charged me $40 for the repair too...new prop comes in tomorrow and we will be back in business....

Re: Planing issue
 

Went with a 20 inch pitch, 4 blade cupped prop. It has good low end and mid range performance, but it just wont get me to that 46-4800 rpm range. Most I could get was 4300-4400 trimmed out. Looks like Its back to the drawing board. Anybody run an 18 inch pitch? Experiences with those?

Re: Planing issue
 

Why go 20 to 18 when you can go 20 to 19? Each pitch is good for a 200 RPM change.

Sent from my DROID RAZR HD using Tapatalk 2

Re: Planing issue
 

The 19 inch pitch wouldnt get me on plane with 4 adults in it. The 20 inch gave me good low and midrange power but wont turn the rpms that i need.

Re: Planing issue
 

If the 20p 4 blade gave you low end , the 19p 4 blade will give you more low end plus raise the rpm's to around 4500-4700 WOT. Right in the sweet spot for your boat.
You will loose a little on the top end , but your engine will like it a lot better. :)
It's really hard to get top speed and holeshot at the same time. You pretty much gotta give on one end or the other.

Re: Planing issue
 

Most run the 19" 3 blade with your size boat but even two similar boats with matching props dont always perform the same. If you are at a max of 4400 rpm with the 20" - 4 blade and you still want some additional bite to go with higher rpms, dropping to the 18" pitch will provide that but....it will also reduce your top speed. Did you buy an aluminum or SS prop? Did you buy/install the Smart Tabs yet?

In general this is what usually happens:
Lower pitch = higher rpms = lower top speed
Higher pitch = lower rpms = higher top speed

Re: Planing issue
 

I didn't get the smart tabs yet and my overall concern is getting out of the hole and on plane. I don't care much for top speed. I found a local prop shop who will let me try out props...the 19" only got me to around 4500 rpms..the boat is full of fuel so I'm gonna make a few wot runs and see what happens with different pitch props. Also I did check the tach and it is reading accurately. In theory, lets say you went down to a 17 inch pitch....it would rev beyond the wot range, but you can utilize the throttle to keep it down to 4700-4800? As opposed to a 20, which at wot only achieves 4300 with the hammer down....the prop is aluminum

Re: Planing issue
 

I went from a 15P 4 blade stainless , to a 17P 4 blade stainless after the install of the Smart Tabs on my Diablo. With no issue.
Personally , I'd put tabs on her and then play with the prop.

Forgot to mention.........I usually run at 7000 ft elevation.:rolleyes:

Re: Planing issue
 

But that is precisely what the Smart Tabs will do for you and by installing them, you dont have to play with the prop pitch as much.


Doesn't quite work that way. Just because you dont run at WOT (which with a 17 should have you around 4900-5000) doesn't mean you aren't using more fuel than you should be. By dropping the prop pitch you increase the rpms throughout the entire acceleration range which in effect means your engine is running at a higher rpm than it should to achieve the same speeds and thus using more fuel. I think that if you install the Smart Tabs, they will provide some stern lift which gets you on plane faster and creates less drag in your arse (of course so would a few less Big Macs :) ) which in theory should add up to 2 mph at WOT. They are the closest thing to "the best of both worlds" that i've seen to date. See if your boat shop has a 19" - 4 blade that you can try as well as the 18" you were thinking of.

Re: Planing issue
 

I'm tellin ya mikey, that poutine is like edible gold! Thanks for the replies gents, once I get the smart tabs installed I will pay him a visit and match the prop perfectly

Re: Planing issue
 

Don't underestimate the effect Smart tabs will have on your boat. it's like a Mariah was made for them.
And as for the pitching of your prop, think about it like this.
it's like changing the wheels on your truck. if you put smaller wheels on it you would get higher revs on your engine but you wouldn't go any faster. in fact probably slower!
And if you put bigger wheels on it the engine would struggle of the line but would eventually run on to a higher top speed at lower revs, if the engine could turn the wheels at higher rev's that is.
it's a case of finding that sweet spot for your setup and how you like to drive the boat.

so my advice would be as the guys have said, get the tabs on then find out how you want to change the way the boat drives. getting the stern out of the water make a lot of difference to the way these boats performs :wink_thumbup:

This is me with tabs on, I know my boat is smaller and lighter than yours, but I also have less power.
running straight and level
http://i681.photobucket.com/albums/v...tled-1copy.jpg
yes I know i'v posted this picture before http://www.cosgan.de/images/midi/froehlich/d010.gif

Re: Planing issue
 

Andy I watched that video you posted and i really like the way you boat rides and sounds. Seems like it just rips across the water. I am currently in the process of looking at the tabs. Although with this sh*t weather were having I haven't been out on the water much lately anyway...

Re: Planing issue
 

Well it's 27*c/80*f here in sunny Southampton UK.
Can't get out today but gona make dam sure the boat gets wet tomorrow :yes_grin: