Props

[ecoastkid]

I literally know nothing about this subject. I have read some of the discussion you guys have about changing them and I'm always left with more questions then before.

This is my first boat and the only boat I have any significant time piloting so I don't have anything to compare too.

I feel like my boat is a bit sluggish off the line and seems to take too long to get on plane but honestly I cant really judge if its good or bad.

Can anyone point me to a good read or suggest how I might begin to measure weather or not its doing well? Also, what are the symptoms of some of the things I read, for example cavitation.

Unfortunately I do not know what kind of prop I have and wont be pulling the boat out of the water for 3 more weeks to check it. However my boat came with a 2nd prop under one of the seats. It has 4 blades and the stamped numbers are either BE1320 or BE1820.

So please...someone explain it to me like I'm 5..lol

[Infinity]

I literally know nothing about this subject. I have read some of the discussion you guys have about changing them and I'm always left with more questions then before.

This is my first boat and the only boat I have any significant time piloting so I don't have anything to compare too.

I feel like my boat is a bit sluggish off the line and seems to take too long to get on plane but honestly I cant really judge if its good or bad.

Can anyone point me to a good read or suggest how I might begin to measure weather or not its doing well? Also, what are the symptoms of some of the things I read, for example cavitation.

Unfortunately I do not know what kind of prop I have and wont be pulling the boat out of the water for 3 more weeks to check it. However my boat came with a 2nd prop under one of the seats. It has 4 blades and the stamped numbers are either BE1320 or BE1820.

So please...someone explain it to me like I'm 5..lol

Once you know what prop is on there (if you look at the prop hub right where the nut goes against the prop you will see the manufacture, the prop number and the diameter and pitch, diameter is always listed first, then the pitch. It would look something like this: (ACME 1847 14 X 14.25). (This is an ACME prop, the prop number is #1847, the diameter is 14" and the pitch is 14.25"). I say this cause the BE1320/BE1820 you listed above is not a number I have seen before, make sure you are not looking at the back of the prop hub.

Then call ACME and they can recommend a prop based on what you are trying to do, they have a lot of data on different boats. They will ask questions such as, the year, model and engine size on your boat. What elevation you are at. What you are looking to do whether its get more speed for something like ski, or load up the boat with ballast and surf (so how much ballast you are running). The faster the boat is at top end, the less low end torque you will have and vice versa. They will also ask what prop you currently have on the boat and how its currently working for low end and top end, may also ask what your top speed is when no ballast and what rpm boat is at, when at that speed. Doesn't mean you have to know every answer to get a good recommendation since they have a lot of historical data for most boats, but the more you know the better a recommendation you will get. What you DO need to know for sure is what prop you currently have on there and the elevation you are at since the higher elevation you are at the less power you boat will make so adjustments need to be made (like extra pitch is needed at 5000ft elevation compared to 1000ft elevation.
In my experience, Nettles Prop in Austin, TX has some of the best pricing on new props and are also quite good at doing repairs if you ding or bend a prop. Also if you buy a new prop from them they will give you $50 coupon for when you do need a repair done down the road.
WakeMakers.com also sells most ACME props and you can use their website to look up the prop numbers, there pricing is fairly good as well from what I have seen.

Each prop # has a different diameter and pitch, you can only go so large on diameter depending on your boat model since if prop gets too close to hull (3/4" is closest recommended), then you can get "prop burn" on bottom of your hull, it can actually etch into your gelcoat which will require repairs. The more pitch you have = more low end torque to get you on plane or to push extra ballast weight for surfing. While going fast may not matter, its good to consider that side too since you want a decent cruising speed and you want to be able to get close to your WOT rpm so you don't overrev your engine and cause damage.

For instance on my boat, I use an #1847 or #1433 prop, both props are 14" dia X 14.25 pitch....the cup on prop is just slightly different. At 800ft elevation where I boat and adding almost 5k lbs of ballast for surfing, I have great low end, surfing speed at 11mph and engine is running approx 3200-3400rpm depending on the angle of my center trim plate. With no ballast loaded, I can also hit my 5400-5600 rpm limit at top end doing just under 40mph (I have the ZR409 engine in my boat). While I rarely run top end speed, I did test it when I got prop to be sure it was within specs, that means that I can cruise down lake at 25mph @ 3500rpm and do 30mph @ 4000 rpm (25mph is my normal cruising speed since its where the engine is the most economical on fuel and I am not overworking it). Also on most boats, its not recommended to run boat for extended periods over 4000rpm tho if you do proper maintenance on boat and are changing oil every 50hours, etc....you are not likely to hurt anything. My OCD is just always in overdrive when it comes to my boat. If you are new to this, be sure to research the maintance needed on things like Impeller replacement, engine oil changes, fuel filters changes, etc. This way the boat will be healthy for you for a long time to come.

**If you have the ZR6 engine in your boat, Its rated at 375HP @ 5000rpm so different specs on your engine than what I told you on my engine above**
http://www.planetnautique.com/Correc...s/ZR6Specs.pdf

Hopefully this helps you out. Sounds like previous owner maybe had a prop that was made more for top end for things like skiing and you want a prop that will get you out of water quicker and on plane.....which will also be better for adding ballast and surfing if that is what you are wanting.

Also....if you post more detailed info on your boat (the info listed above that ACME would also need), there are people here with the same boat that can help recommend a good prop depending on what you are wanting to do. The ZR6 is a good engine and should do great with the right prop setup no matter what your end goal is. The right prop can totally change how the boat reacts.

[Tallredrider]

Especially if this is your first boat, then it is a matter of time until you wrap the rope around the prop. At that time, you will wish you had a pair of goggles and a sharp knife on the boat. Even experienced boaters get out of sorts and manage to wrap the rope up on occasion (not me, I am way too smart for that). Goggles are also often the difference between unwinding the rope and just giving up and cutting it off.

Buy yourself the goggles now and leave them on the boat. When you have a spare moment, hop in the water and see which prop you have.

[ecoastkid]

Great advice. I appreciate it. Also thanks for the info.

My boat is a 220 SANLE zr6 with the two rear factory ballast tanks (no belly tank). Elevation is just below 1200 ft. For now, my general use is towing tubes and a kneeboard. Hoping to move the kids to a wake board and then perhaps get some bigger ballast and a wake shaper so they can try wake surfing.

I'll be on the boat on the 4th so I'll confirm my recollections but I'd say my boat is def geared(propped? lol) for top end as you suggest. IIRC, I'm around 2500rpm @ 25mph. Also I can hit 40-41 and be just under 5K. I don't like leaving it hang over 4k as well so I usually keep my top speed to 35ish and generally cruise 25-30.

When I start off from a stand still, it seems to stand up and plow for a good few seconds before its up on plane. Perhaps I'll video it and then see if I can see how long that is. Also I can set my perfect pass so it beeps and do 0-10, 0-20, 0-30, and 0-40 pulls. I'll post my results and see if I can compare to how others are doing.

[ecoastkid]

So I did my speed pulls and found that my boat would do 0-40 in about 16 seconds...I'm happy to report that I was right...It was sluggish.

I changed the spark plugs yesterday and was amazed at the power dif. It dropped to 10 seconds (Both pulls video verified)...Feels like twice the hp. I'll put up a separate post about the plugs.

I think I'm satisfied for now but as I get more experienced I may revisit the prop idea.