[theraami]

Hi there,

Could someone give me opinion what seems to be goog prop for SC19 with 3,0 engine?
I ask because I have big big difficulties to get my boat planing when there is more than three people onboard. We tried wakeboarding too, and that was almoust hopeless... I'm not experienced concerning boats (or english language!) and this is my first boat. I only know it has 3 blades and it's aluminium. Maybe I have too small engine too?

I'm not so intrested about top speed, main thing is to get it planing easily.

Link to my boat:

Mariah SC19 moottorivene 2006 - Nettivene

(In Finnish, sorry)

Rami

[mikeyt]

hi Rami. Just as a learning guide, read thru our Basic Propellor rules and give yourself a little education on how to choose a prop.

That said... yes a 3.0L is a small engine in a 19' boat but it can be made to plane easier. We really do need to know what prop is on your boat now though. If you take the prop off the boat and look at the backside you should see the size printed around the hub of the prop. It will look something like 14.25 x 19. The 14.25 is the diameter of the prop and the 19 is the pitch of the prop blades. In theory 1 revolution of the prop should move you forward 19".... but reality gets in the way of theory an awful lot.

I suspect your boat has a 19" pitch prop. If that's the case then you can change that over to an 18" - 4 blade prop which will give you more 'bite' in the water. You can also consider buying and installing a set of Smart Tabs which many of our members have done. The Smart Tabs provide lift at the stern and gets your boat onto plane much faster as well as keeping there at lower speeds. The tabs also provide a bit of stability at speed and reduce that low speed 'wander' that is inherent in most smaller runabouts. You can click on this link to read up on Smart Tabs. Your boat will work nicely with the 60lb actuator arms.

[theraami]

Originally Posted by mikeyt

hi Rami. Just as a learning guide, read thru our Basic Propellor rules and give yourself a little education on how to choose a prop.

That said... yes a 3.0L is a small engine in a 19' boat but it can be made to plane easier. We really do need to know what prop is on your boat now though. If you take the prop off the boat and look at the backside you should see the size printed around the hub of the prop. It will look something like 14.25 x 19. The 14.25 is the diameter of the prop and the 19 is the pitch of the prop blades. In theory 1 revolution of the prop should move you forward 19".... but reality gets in the way of theory an awful lot.

I suspect your boat has a 19" pitch prop. If that's the case then you can change that over to an 18" - 4 blade prop which will give you more 'bite' in the water. You can also consider buying and installing a set of Smart Tabs which many of our members have done. The Smart Tabs provide lift at the stern and gets your boat onto plane much faster as well as keeping there at lower speeds. The tabs also provide a bit of stability at speed and reduce that low speed 'wander' that is inherent in most smaller runabouts. You can click on this link to read up on Smart Tabs. Your boat will work nicely with the 60lb actuator arms.

Hi,

Thanks a lot for useful tips.
I took the boat out of water and was able to see my prop. It says 832830A45P19 so I guess it's 14,5" wide and pitch is 19".

When I bought this boat I had 4 blades prop, but it was not long time when I found my first underwater rock. (I named it Rocky VII btw) But then the local boat dealer suggested this 19" three blade version, and it feels like it's "slipping" in hard accelerations, or in heavy loads.
I guess I will order both, 4-blade prop and smart tabs afterall...
Thanks again.

Rami

[mikeyt]

Originally Posted by theraami

Hi,

Thanks a lot for useful tips.
I took the boat out of water and was able to see my prop. It says 832830A45P19 so I guess it's 14,5" wide and pitch is 19".

When I bought this boat I had 4 blades prop, but it was not long time when I found my first underwater rock. (I named it Rocky VII btw) But then the local boat dealer suggested this 19" three blade version, and it feels like it's "slipping" in hard accelerations, or in heavy loads.
I guess I will order both, 4-blade prop and smart tabs afterall...
Thanks again.

Rami

Let us know how it works out!

[theraami]

Sure I will, but you need to wait a while. Our lakes are frozen now for four months...

[Andy b]

There are many things that may be going on here,
With both you and your boat,
You say that you have limited experience when it comes to driving boats,
Have you had anybody on board who has experience?
Do you know how to trim the boat for the hole shot, and then getting it over the hump to plane?

What Rev's are you getting on the engine?

The 19" prop on your boat should be fine. In fact most boats of your size with 3.0l motors will run them,
but was the prop new or second hand? Because from what you've said it sounds a lot like the hub may have been spun!

You say that you hit a rock with a stainless prop! Stainless props are very hard on the gears in the leg if they hit anything.
Is there any nasty noises coming from the leg when running?

But with all things check the simple stuff first before you start spending large amounts of money trying to fix problems that don't exist!
Try to borrow another prop that you know is good and go from there. Then when you've got it planning fit the tabs

Your boat should be able to do 35/40mph no problems even loaded. Plenty fast enough to plane and tow toys.

[theraami]

Originally Posted by Andy b

There are many things that may be going on here,
With both you and your boat,
You say that you have limited experience when it comes to driving boats,
Have you had anybody on board who has experience?
Do you know how to trim the boat for the hole shot, and then getting it over the hump to plane?

What Rev's are you getting on the engine?

The 19" prop on your boat should be fine. In fact most boats of your size with 3.0l motors will run them,
but was the prop new or second hand? Because from what you've said it sounds a lot like the hub may have been spun!

You say that you hit a rock with a stainless prop! Stainless props are very hard on the gears in the leg if they hit anything.
Is there any nasty noises coming from the leg when running?

But with all things check the simple stuff first before you start spending large amounts of money trying to fix problems that don't exist!
Try to borrow another prop that you know is good and go from there. Then when you've got it planning fit the tabs

Your boat should be able to do 35/40mph no problems even loaded. Plenty fast enough to plane and tow toys.

Hi Andy,

I might be inexperienced, but boat is not that complicated thing to handle.
I had friends onboard with years of boating experience, and they all agree, like me, that is very hard to get planing when people onboard. I have also tested three different, but same size of boats and my one is the worse one. I never mentioned stainless steel prop, the old one was also aluminium. But it doesn'tt matter anyway, because even I hit the rock it in very slow speed, my insurance company paid/changed whole sterndrive for me, so it's new and this 19" prop is also new. My top speed is 37mph, and with lot of fat inside, around 32mph.

[mikeyt]

3.0's on this side of the pond generally run props between 17" and 19" depending the boat & what it's primarily used for. You're asking a lot of your 3.0L to push around a 19' boat with 3 or more full size people in it and still plane easily as well as pull a toy around. And given the water you boat in, it sounds like it will be wise to have a spare prop on board your boat and a 19" 3 blade will be a good one to have. Switching over to the 18" 4 blade and adding Smart Tabs will have a significant effect on your planing ability and the prop change & Smart Tabs will take a considerable load off that engine.

You can always throw that 19" back on if there is just 1 or two of you going for a day cruise. Just shift a little of your heavier storage items towards the front of the boat and that should help too.