New boat owner seeking prop advice

[pec2402]

I just purchased my first boat 2 weeks ago! here are the details:
2004 Larson SEI 18ft
Volvo Penta SX 4.3L 190hp

I've only had it out a few times and today i ran into my first problem...i thought i was far enough from shore (no depth finder, will invest in one now!) and i hit what had to be rock with my prop. I wasn't going fast, just trying to avoid boat traffic, but it ate the prop up (original prop - 14.25 x 23 volvo).

Luckily, i did no other damage to the boat, but i do need a new prop because it actually took a chunk out of one of the blades and badly damaged the rest.

I'm hoping to get advice before i order a new prop this week. Should i simply stick w/ what it came with (3 blade 23in pitch)? Or look into another brand? More/less pitch? Maybe even a 4 blade prop?

I've read a lot of the forums but i figured it would be helpful to describe my situation and hopefully get some good feedback.

Currently, the boat tops out around 50mph with 3 people onboard, but i haven't paid much attention to the rpms because i really didn't think it was affecting anything since it's the original setup.

Thanks in advance for any help/suggestions!

 

[Bondo]

Re: New boat owner seeking prop advice

but i haven't paid much attention to the rpms because i really didn't think it was affecting anything

Ayuh,... Without that little tib bit, I wouldn't even venture a Guess....
Go back with what you had I guess...

 

[steelespike]

Re: New boat owner seeking prop advice

Your prop sounds pretty beat up but props can be repaired for less than new would cost.Wouldn't hurt to take it to a prop shop and see what they can do.
Then you could get some performance figures so you have a base line.
Give us the figures and your typical activities.We can get an idea if you need a prop change. Otherwise stick with the same size prop.Let the diameter fall where it may as long as its within about 1/4" of original, avoid extremes like 3/4 to and inch difference.

 

[pec2402]

Re: New boat owner seeking prop advice

Thanks for your help!

I am going to call a local prop shop and see if it's possible to get my current volvo 3 blade repaired...but i did find this thread:

http://forums.iboats.com/showthread.php?t=399135&highlight=larson

and i ended up ordering the same prop (Solas Rubex 4 blade alum 14x21) because my setup is the exact same (although a few years newer). Volvo Penta 4.3L 1.79 ratio. Also, i like the pros of the 4 blade for hole shot performance considering i plan on skiing a good bit next season and typically have 4 people on the boat at a minimum.

As long as i get the prop by this weekend, i'm going to test it out...i'll let you know how it goes.

 

[boehmbros]

Re: New boat owner seeking prop advice

i had the same problem. what i had was a 23 pitch 3 blade prob. i switched to a 4 blade with a 15 pitch. the take off was a huge difference. before i would have 4 people in the boat and im not even kidding you it took about 12-15 sec to take off. now with 7 or more people in the boat with a wakeboarder on the back it rips us right out of the water. when you get a prop with less pitch your rpm's will go up and you will loose top end. look at what your motor is suppose to be at in rpm's wide open. most boats max is 4500-4800 rpm's. it all depends on what you want your boat to do also. best of luck!!

 

[QC]

Re: New boat owner seeking prop advice

Be very careful with info like that ^^^^^

Yes dropping pitch improves acceleration or "hole shot", but raising pitch does not necessarily improve top end. Also, unless the boats are identical, this info could be dangerous. A switch from a 23 pitch to a 15 is almost unheard of unless the 23 was so far off to begin with. As far as RPM recommendations are concerned, depending on the engine model and make, there are swings from 4200 to 5200 with current I/Os. We need to keep all of these responses narrowed to exactly what the guy is dealing with. Other experiences can be helpful, but not without completely understanding the differences between the base setups. This includes even altitude information

For the OP, I may have missed it here, and it almost sounds like you've got this in your plan. If you repair the old one, and also get a new one (you mentioned a 4 blade), you get some great benefits. 1) two sets of data, which can help the understanding of this topic and 2) You end up with a spare, so when (not if, when) you damage your prop again, you can switch them out in less than 5 minutes and your day is not impacted as long as you don't pout too much about t hitting bottom

Take a read of the stickies at the top of the Prop section. They can help you with a base understanding of this topic.