Another Newbie, Another Prop Question...

[bedpan]

Hey Folks. Been trolling through the forums the last coupe of days. Finally decided to register and throw my question your way. I have read enough of the Prop type questions that hopefully I can answer most pre-req info. That said however I am missing some RPM info to make this truly an educated prop decision. Just trying to find a starting point for the season that I can build upon.

1) Performance issue you are trying to correct.
- Current composite prop is broken, and stainless has some nicks. Want a new Composite or Aluminum and keep the Stainless as a backup. Liked the performance of the Stainless though.

2) Current prop manufacturer, model, aluminum or stainless as a minimum.
- 13 Spline
- Stainless - OEM Part Number - 389510 3 blade - 13" x 19 Pitch
- Composite - No Part Number - Made by ComProp - 4 blade 13.5" x 15 Pitch

3) Current prop diameter and pitch (required).
- See above

4) Wide open throttle RPM and speed with an average load (very helpful)
- Not sure.. Boat is back in the water in about a month. Just looking for a starting prop.......
- Remember being up around 4300RPM at WOT but this is just a guess. This would be on the Composite Prop if I am right.

5) Engine/drive make, model, year, and HP
- OMC 3l, believe the engine is an 1988 (boat is an 1989)
- Based on what I am reading on the wonderful internets its 130 or 140HP


6) Boat make model, year, length and weight
- 1989 Marvac 17' - Bowrider
- Not sure about weight
- 4 People around 470lbs almost always in the boat
- No much gear, 4 or 5 fishing rods live in the boat and some light gear. No much else.
- No Kickers, trolling motors etc and only one battery for the motor

So adding a little to this....
Young family Mom, Dad and kids 5 and 7.
I am new to boating. I bought the boat Late 2011 season used not really knowing what I was getting into. Well other then falling in love with being in the water it has also sucked up some money fixing things up. Might be in the market for a new boat in the next couple of years but for now I need to make the best of the ol'Marvac.

Usage is general run about with the family. Some day trips through life locks, a little tubing, some fishing. Not a big fan of going fast so just want to keep things running well with out any unneeded engine stress.

We are on Upper Buckhorn Lake in Ontario. It is a shallow lake that gets quite weedy. I have bounced off the bottom a few times now trying to get to a few fishing spots. The last time was just before we pulled the boat out of the water for the winter and I damaged the Composite prop.

I put the stainless prop on at this time and loved the performance of it. Lower RPM at reasonable speeds and despite what I am reading seemed to sit on plain a little easier at low RPM as well.

Long story. I guess the only other thing to add here is what I think I am looking for. Again I am new to boating and don't claim any knowledge of my own, just what I have read the last couple days trying to sort this out.

Would love to just leave the stainless on, but as I have had some prop strikes in the last couple years and project it will happen again I think I should be going with something softer to protect the lower unit. Not sure if I should track down another Composite or go Aluminum. Hub System or no Hub system, what pitch would be a good starting point? Brand, suggested company to order from?

Sorry for the overly long post. I know I don't have all the answers to make the most informed decision but I hope to do the best I can with what I have. This season will be attacked with a lot more understanding of props so I will try and track some data....

Thanks!

Mike

***
Edit
If it helps I can post pics of the boat and/or props as well.

 

[steelespike]

Re: Another Newbie, Another Prop Question...

It would appear that a 19" prop works for you.
I would start with your 19" prop and get us the wot rpm and speed.
Lightly loaded. We need the rpm and speed to evaluate your setup.
Based on your rpm It appears you may need a little less prop.

 

[bedpan]

Re: Another Newbie, Another Prop Question...

Thanks for getting back to me..

Sort of what I was thinking, heading more towards the Stainless spec wise.

Thoughts on material. Aluminum or try and find another composite? Stick with 19" pitch or adjust for the change in material? Also anyone wise an knowledgable want to lead me to going to a hub system or sticking with a normal prop?

My thoughts are 19" pitch Aluminum on a hub. Thoughts?

Thanks again,

Mike

It would appear that a 190" prop works for you.
I would start with your 19" prop and get us the wot rpm and speed.
Lightly loaded. We need the rpm and speed to evaluate your setup.
Based on your rpm It appears you may need a little less prop.

 

[jestor68]

Re: Another Newbie, Another Prop Question...

The best bang for your buck would be a Solas Rubex 19 pitch (aluminum).

Your motor's full throttle rpm range is 4200-4600 rpm.

All modern props use a "hub". Some are pressed in at the factory, while others are replaceable(inserted by you when you mount the prop). Solas Amita are pressed in, while the Rubex uses their replaceable hub.

They perform the same, but the Rubex can actually be cheaper because the I boats price includes the hub kit; while the Amita should be purchased with the Solas thrust washer(extra). In most cases, this makes the Rubex about $9 cheaper.

 

[bedpan]

Re: Another Newbie, Another Prop Question...

Thanks for the reply... I look forward to getting in the water and testing out a new prop... Hell just being on the water. Just east of Toronto today we are in a Winter Storm warning right now. The kids school bus was cancelled yesterday and today. Welcome to April! Just 27 days until our trailer opens and the boat hits the water!

Regarding Prop selection. If I read this right the spacer and thrust washer is built into the hub on the Rubex, ie. not required, where the Amita uses a traditional spacer and thrust washer?

Two questions I am sort of left with at this point..

1) Is it really safer to run Aluminum or Composite as compared to Stainless. Being reading a lot the last day or so and seeing some people and companies advocating SS for almost all applications. They describe the Hub as providing the protection on the SS. As such SS can become cheaper then replacing a couple aluminum props. Thoughts?

2) What about Composite? The broken prop I have is from a company called Comprop. There website sucks (COMPROP Propellers). This prop has lasted me the better part of a couple seasons with a couple strikes. Other then increasing the pitch to 17" or 19" this might be an option as well?



Right now I am leaning towards a Aluminum prop with 19" pitch. That said I am tempted to get my SS one cleaned up and try it for a bit.

Cheers folks and thanks for reading!

Mike

The best bang for your buck would be a Solas Rubex 19 pitch (aluminum).

Your motor's full throttle rpm range is 4200-4600 rpm.

All modern props use a "hub". Some are pressed in at the factory, while others are replaceable(inserted by you when you mount the prop). Solas Amita are pressed in, while the Rubex uses their replaceable hub.

They perform the same, but the Rubex can actually be cheaper because the I boats price includes the hub kit; while the Amita should be purchased with the Solas thrust washer(extra). In most cases, this makes the Rubex about $9 cheaper.

 

[Georgesalmon]

Re: Another Newbie, Another Prop Question...

Getting your SS prop rebuilt and running it to get the information you really need about performance makes the most sense. Then you can buy with a lot more confidence, and you won't lose any money or boating season. A fixed up SS prop can be sold to recoup the cost of a new AL one or kept for a spare like you said.

 

[bedpan]

Re: Another Newbie, Another Prop Question...

I am hesitant to run the SS as my lake has a lot of hazards. Early season as well not sure if things have shifted at all with all the ice. Regardless I am am thinking I should bring the SS in to be cleaned up. Its not terrible just a couple little dings. For the record I am not responsible for those dings though. It came like that ;-) I take full responsibility for the Composite prop though. That said I have not idea what or how it happened.

Getting your SS prop rebuilt and running it to get the information you really need about performance makes the most sense. Then you can buy with a lot more confidence, and you won't lose any money or boating season. A fixed up SS prop can be sold to recoup the cost of a new AL one or kept for a spare like you said.

 

[Georgesalmon]

Re: Another Newbie, Another Prop Question...

Couple little dings? Got a file?

 

[bedpan]

Re: Another Newbie, Another Prop Question...

Again being "Another Newbie", I was not sure how much is to much. Couple comments from around the park last season said bring it in, or get a file.. Leaves me in the pickle of who knows ;-)

Here is a pic. Not the best as my Father-in-law took it a couple days ago for me. Boat is stored at his place for the winter.


https://www.googledrive.com/host/0BwxcD2SubWa4OEphVWYzRzRTazQ/ss.jpg



Thoughts?

Mike

Couple little dings? Got a file?