aluminum to stainless, I have the specs.

<peewee>

Recruit
Joined
Aug 17, 2009
Messages
5
1. Year, make and model of boat
2002 sv1700 Sea Pro
2. Length, width and base weight of boat, look for boat decal on back of boat
17 feet long, 7?4? wide, 1000 lb
2a.What is the recommended HP for your boat
max 115 hp but I have a 90 merc salt water series 2002 model.
3. Number of people and gallons of gas normally on boat
2 people, 25 gallons
4. What do you use the boat for
fishing only
5. Is it a Deep Vee and if so how many degrees of deadrise
not so deep, 15* deadrise.
6. Year, make and model of motor
2002 mercury 90 salt water series elpto
7. HP and gear ratio of motor IMPORTANT
If you don?t know the ratio, you need to pull the plugs out and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing and turn the motor until the tape lines up with each other, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
2.31:1
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
5000-5500
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
1 inch or so, hard to tell.
10. Is it a bass boat or does it have a pad bottom
Center console , I?m not sure of this question.
11. Does it have a hydrafoil, dolefin or trim tabs
no
12. Make, model, diameter, pitch and whether SS or aluminum prop
aluminum Michigan wheel 12.75x21
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. If you do not have a tach you can buy a Tiny Tach for $ 50
5300 rpm, 2 people, 25 gallons gas, 34 mph by gps
14. Are you at sea level or a higher elevation, give us the elevation in feet
Sea level. I 100% use my boat at the coastal areas
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the foregoing could be the reason your prop is not attaining full RPM No, I just purchased this boat, it was well maintained at the dealer according to the previous owner.
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop. Don?t know how long, the prop has lost all paint and is pretty chewed up with small nicks on the perimeter of each blade.
17. Does the prop show any damage that you can see
Yes, it doesn?t look un-usable, and it does the job but is scarred a bit.
18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations
I am looking to put on a Stainless prop for better performance, I want more speed at lower rpms for cruising to the next fishing hole and better fuel consumption as well as better top end speed.
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT. I will this weekend but my question for now is what will be the consequences of going to a 13.5x21 prop being that I can?t find one that is the same size as my aluminum?
And shouldn?t the stainless be a noticeable difference from the aluminum I have now?
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: aluminum to stainless, I have the specs.

Peewee, right now you have a prop slip of 25% which is very high and might possibly have to do partially with not having the motor raised high enough on the transom. There is no way you can run a 21" pitch stainless prop on your boat as it is now.
The first thing you need to do is move the motor up at least one notch on the transom. If you can I would like you to post a picture of your motor showing us the keel and the anti ventilation plate with a board reaching the anti vent plate from the keel. And also a picture showing the motor mounts on the transom and then run the boat and get me the RPM and speed numbers I need to run a full analysis.

Anti ventilation plate

AntiventilationPlateStraightEdge-2.jpg



Prop Slip

peeweePropSlip.jpg



H
 

<peewee>

Recruit
Joined
Aug 17, 2009
Messages
5
Re: aluminum to stainless, I have the specs.

thank you so much for the info, I will get you some pictures today although I won't be able to run it until Friday.
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: aluminum to stainless, I have the specs.

That sounds great.


H
 

<peewee>

Recruit
Joined
Aug 17, 2009
Messages
5
Re: aluminum to stainless, I have the specs.

here are some pics of my setup, notice the condition of the prop. The board is no more than an inch below the cavitation plate. I only have one more hole to raise it. The board is even with the bottom of the boat, I couldn't hold the camera and get both the motor and the boat in the same pic.
 

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hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: aluminum to stainless, I have the specs.

Pewee, it is hard to tell from pitures but it appears to me that you definitely have a grounding problem on your boat beause of what I see eaten away on the prop. I will be waiting for your numbers.


H
 

<peewee>

Recruit
Joined
Aug 17, 2009
Messages
5
Re: aluminum to stainless, I have the specs.

Grounding as in electrical? What can cause this? My Anodes are a little pitted and I probably need to get new ones. The little wire cables that ground the motor to the transome are in perfect condition. You guy's are the experts, is there a reason for this grounding? I noticed after I left my boat at the dock (in salt water) with the motor down until the next morning that my prop looked more tarnished, but from the moment I bought the boat (used) the prop has looked this way.
 
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<peewee>

Recruit
Joined
Aug 17, 2009
Messages
5
Re: aluminum to stainless, I have the specs.

The dull part of the pic is where the paint has been off since i have had the boat, the shiny part is where the paint has come off since i have taken the boat out fishing 4 times. I have only had it a month. Thanks for the link on how to check my boat. I am an industrial battery and charger tech so hopefully between you and I, we can figure out why this is happening. Of course any other input is appreciated.
 

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hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: aluminum to stainless, I have the specs.

With your bakground I am sureee you will find it.


H
 
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