New to Forum / New Boat / Selecting the correct prop

[Pedro19]

I know that there has probably been thousands of questions around selecting the correct prop. I am am just looking for some advise around my specific situation and a new boat that we just bought. Just bought a 1994 Sea Ray 220 Select Bow Rider with a 260hp 5.7 , Alpha 1. The lower unit says 1.5 on the outside so I am thinking it is the 1.47 gear ratio. Boat only has 200 original hours on it and looks brand new. However, all three blades on the alum prop are bent so I will be in the market for a new prop. When I test drove the boat, when I was running at full throttle 4500 RPM, I was only running about 40 mph if the speedO was working correct. I think that it was partially because the prop is bent that it was not performing very well as I could also feel a little vibration as well. Instead of trying to referb this one, I am going to just buy a stainless steel but not sure what I should buy. Original prop looks to be a 3 blade 17p. We are a family of 5 and while we are not avid water sports family, the boys do like to ride the wake board from time to time and we also like to go tubing. We also love to boat ride and I would love to be able to cruise at around the 40 mph mark pretty comfortably. Not expecting a speed boat, but wanting to pick the best all around prop that will get me up and out of the water while also giving me some comfortable cruising. Any thoughts ? Thanks

 

[Mcfltfyter]

Speedometers are pretty notorious for being way off, especially when they are 30 years old. Either the engine is not running great, or it just can't handle more prop based on rpm. It would be a good ide to check the accuracy of your tach also so you dont end up chasing rainbows.

 

[Pedro19]

Could all three of be blades being bent be the culprit?

Speedometers are pretty notorious for being way off, especially when they are 30 years old. Either the engine is not running great, or it just can't handle more prop based on rpm. It would be a good ide to check the accuracy of your tach also so you dont end up chasing rainbows.

 

[Mcfltfyter]

I'm really not an expert, but it calculates to 19% slip, which I wouldn't think is terrible for a damaged prop. I guess it depends on how it is bent?

Then again, you really have no idea of actual speed. Even if your slip was 10%, you'd only be at 44mph. 4mph accuracy is a lot to ask of that speedo.

 

[Mcfltfyter]

You were trimmed out for max rpm, correct?

 

[QBhoy]

Hi.
can be a guessing game if using dash tacho and speedo, to be fair. But what I can almost certainly assume and tell you is.
your drive as stamped is a 1.5. They came later in 1.47.
you won’t be able to turn a 19” well at all on that set up. So anything that size is out.
likely a 17” would be a good all rounder I’d think. But I’d think you’d be able to run close to the max 4800 rpm with that. You seem to be down on rpm there. But could be down to the tachometer. Hopefully not a health issue. I’d be messing around the 17” size and making sure all else is healthy. Take it from there.
incidentally, what kind of speed were you expecting ? You aren’t going to see a genuine 50 mph, I’d think. Mid 40’s would be great going really.
Trim, weight, fuel and conditions make a huge difference to speed usually...anything over 40 mph. If I left the trim down on one of my boats...it would only do late 50’s tops. Trim her up and there is like 10 mph extra. Full tank and a quarter tank is about 7 mph difference. Extra body or two on...7 mph loss easy. Past a certain speed...tiny tiny things matter and have an effect. Hope that helps.

 

[Pedro19]

Hi.
can be a guessing game if using dash tacho and speedo, to be fair. But what I can almost certainly assume and tell you is.
your drive as stamped is a 1.5. They came later in 1.47.
you won’t be able to turn a 19” well at all on that set up. So anything that size is out.
likely a 17” would be a good all rounder I’d think. But I’d think you’d be able to run close to the max 4800 rpm with that. You seem to be down on rpm there. But could be down to the tachometer. Hopefully not a health issue. I’d be messing around the 17” size and making sure all else is healthy. Take it from there.
incidentally, what kind of speed were you expecting ? You aren’t going to see a genuine 50 mph, I’d think. Mid 40’s would be great going really.
Trim, weight, fuel and conditions make a huge difference to speed usually...anything over 40 mph. If I left the trim down on one of my boats...it would only do late 50’s tops. Trim her up and there is like 10 mph extra. Full tank and a quarter tank is about 7 mph difference. Extra body or two on...7 mph loss easy. Past a certain speed...tiny tiny things matter and have an effect. Hope that helps.

 

[Pedro19]

When you say 19 inch, are you refering to the overall diameter of the prop? So you are saying I should stay w/the 17 inch and 17 pitch? Should I go w/Stainless?

 

[Scott06]

When you say 19 inch, are you refering to the overall diameter of the prop? So you are saying I should stay w/the 17 inch and 17 pitch? Should I go w/Stainless?

He is saying 19" pitch the diameter is determined by the prop manufacturer so just stay focused on pitch. If you are only turning 4500 with a 17" pitch I would no go up in pitch as that will lower WOT RPM.

My thoughts would be to get either your current prop fixed or get to know the boat with a decent condition aluminum like a black max or Michigan vortex. Then when you have a track record with how the boat performs spend the money on stainless. Based on what you mention you may like the way a 4 blade behaves- like a michigan vortex 16" 4 blade. Genrally you give up some top end for better holeshot, more stern lift, and lower planing speed when going to a 4 blade

 

[southkogs]

If you're getting 40MPH on the boat speedo, I would be tempted to put it in the water and take a GPS reading. If you're getting between 40 and 45 on the GPS ... then I would say stay with the prop setup. Either fix the current or get a new one.

That boat tested with the 350 MAG made it up to about 50MPH. The 5.7 will be come in a little lower ... and lots of details go into speed and your bent prop could be costing you a few miles an hour. But mid 40s would be a happy number on that setup.

Plus you're not that familiar with the boat - so some basics tune up kinda' stuff could affect things to the better as well.

 

[Pedro19]

If you're getting 40MPH on the boat speedo, I would be tempted to put it in the water and take a GPS reading. If you're getting between 40 and 45 on the GPS ... then I would say stay with the prop setup. Either fix the current or get a new one.

That boat tested with the 350 MAG made it up to about 50MPH. The 5.7 will be come in a little lower ... and lots of details go into speed and your bent prop could be costing you a few miles an hour. But mid 40s would be a happy number on that setup.

Plus you're not that familiar with the boat - so some basics tune up kinda' stuff could affect things to the better as well.

This makes a lot of sense. Thank you very much for you input. I really wish I knew how much was contributing to the bent prop. I think what I will do is go ahead and just get another prop just like what is currently on there and then see how she performs and go from there. I would love to see 50mph WOT. This would give us a good cruising speed of 40mph I would think. That would be GREAT. I know that we will want to get up and stay up on plane so that we can do the wake board thing though. Thanks again.

 

[Pedro19]

He is saying 19" pitch the diameter is determined by the prop manufacturer so just stay focused on pitch. If you are only turning 4500 with a 17" pitch I would no go up in pitch as that will lower WOT RPM.

My thoughts would be to get either your current prop fixed or get to know the boat with a decent condition aluminum like a black max or Michigan vortex. Then when you have a track record with how the boat performs spend the money on stainless. Based on what you mention you may like the way a 4 blade behaves- like a michigan vortex 16" 4 blade. Genrally you give up some top end for better holeshot, more stern lift, and lower planing speed when going to a 4 blade

I think this is what I will do. I am going to look for another good original prop and see how she performs and then go from there. Thanks again.

 

[southkogs]

This would give us a good cruising speed of 40mph I would think.

I would guess cruise for you to be in the mid 30s somewhere. My boat will hit a little over 40MPH, but the sweet spot for cruise comes in just around 32 or 33 (typical water conditions).

I know that we will want to get up and stay up on plane so that we can do the wake board thing though.

Wake boarding is much more about going a little slower and kicking up a big wake ... more cutting than planing. Your boat should plane out in the mid 20MPH range. For wakeboarding and kneeboarding, you really don't want to go much past that ... get them up, and then mush it in the water to give lots of "wave" for the pull toy. Skiers will want to go faster and want a smaller wake to deal with.

 

[Pedro19]

Would you recommend a 4 blade aluminum for what we are wanting to do, or stay with the original 3 blade? Would the stainless really perform any better? Thanks

 

[southkogs]

Would you recommend a 4 blade aluminum for what we are wanting to do, or stay with the original 3 blade? Would the stainless really perform any better? Thanks

Someone else will have to put their 2¢ in on that. I've never used anything but a 3 blade Aluminum. For general usage - including water sports - I don't personally think it matters that much.

I never did competitive water sports, but got pretty decent on skis and knee boards. Most of my time was behind a tri-hull with a 75HP outboard ... 3 blade aluminum prop. Vanilla. The times I did ski behind a competition boat, there was a difference but it was mainly in hole shot and the table the hull put down.

 

[Mcfltfyter]

I'm in a very similar position and I went with a 4 blade aluminum. I already have gps speed, so I also ordered equipment to know my actual rpm. That should give me a solid baseline to start with. Aluminum Quicksilver props are so inexpensive I can try 4 different props for the price of a stainless, and also have a much better idea what would work best if I were to upgrade.

I'm pretty sure I'll end up with a 17" 4 blade and a 19" 3 blade, but I'm not going to gamble $1k+ on stainless without some testing first.

 

[Scott06]

Would you recommend a 4 blade aluminum for what we are wanting to do, or stay with the original 3 blade? Would the stainless really perform any better? Thanks

I would reccomend a 4 blade for what you are doing - heavier load and fairly big boat for the power (22 ft/260hp). My general use is 6-7 people and go out for an hour of skiing,boarding, and then swim. I have found on my last two boats 4 blades work better for all aspects (holeshot, stern lift, lower plaining speed) of that use except top speed and the amount of time it is calm enough to cruise at 40 mph is almost nil.

While yes the correct stainless prop will perform better, but having the epxerince to select the right one requires some experince plus trial and error. I cut my prop teeth on Michigan Vortex Aluminum 4 blades, relatively cheap. Once I built a knowledge base of props, my boat, and how I like to use it, I started playing with stainless ones. Not a cheap hobby but I generally buy them used off ebay. Its taken me 5 props to find two I like, sold the ones that didnt work as well for about what I paid used. Best way to do this is if you have a prop shop local they generally will let you try before you buy. A few guys like Prop MD, BBlades and General Propellor do it on line I believe.

 

[Scott06]

Someone else will have to put their 2¢ in on that. I've never used anything but a 3 blade Aluminum. For general usage - including water sports - I don't personally think it matters that much.
Depending on how you use your boat, I think it defintely matters on the 4 blades vs 3 blade, but depends on the boat. My old boat 1991 Sea Ray 170 /3.0 L it made a huge difference in pulling out of the water and stern lift. A 16" 4 blade was such a difference vs a 17" 3 blade black max. Basically allowed me to stretch the use of what was essentially a underpowered starter boat. My current boat is a 2004 Sea Ray 200 sport which is a beamy and heavy boat that throws a pretty big wake, a Revolution 4 really helps get the stern out of the water and has enough bite to allow full trim out with out blowing out. With being able to trim fully out I even get a slightly higher top speed vs a 3 blade Enertia which is also a very good prop. I dont think it would be a big a difference on all boats, say if my boat wasnt as heavy, stern heavy, or beamy.

 

[vroom ZOOM]

for stainless, a laser II would be nice on that boat. If you want a budget stainless prop, get a solas, they sell them here on iboats, they are nice props albeit a little cheaper.

 

[QBhoy]

Would you recommend a 4 blade aluminum for what we are wanting to do, or stay with the original 3 blade? Would the stainless really perform any better? Thanks

You’ll lose top end with most 4 blades, pitch for pitch. In general at least. Exceptions would be rev4 and bravo props perhaps. They will put rum most 3 blade modest props. And come close to the decent 3 blade props usually. Like all props though. Can be a hit or a miss. Always best to try them on the boat. Props never stop surprising me.