Continuance of skeg/prop damage

[smitty1258]

The original thread can be found here: http://forums.iboats.com/showthread.php?t=269943

But heres a recap of what happened.

Apparently there is a water inlet for the powerplant, that sits below the surface of the water. It is unmarked and as you can see, does some major damage

Now to the carnage:

So Im in the market for 1-2 new props as you can see

My questions for you guys are what are my best options? I have a 180hp 4.3 V-6 merc cruiser I/O. I cant tell you 100% if this was the stock prop but these are the numbers I got from it.

48 78122 A40 21P

There was also another prop that came with the boat, that was pre chewed up and it was

48 78118 A40 17P


So im looking for some recommendations. Im dont care as much about going fast as I do pulling skiers/wakeboarders, but top speed is cool for those days just cruising.

When its just my family, its only 3 of us. Me 195lbs, wife 110lbs and kid, 120 lbs. + gear like tube, kneeboard,wakeboard, skies, ropes, and small cooler. That is when its just us, about every other weekend we take some more family out, and add another 210lb male, and 2 more kids roughly 150lbs together, and usually same amount of gear.

3 blades vs 4 blades? I dunno you tell me. What brand and type?

 

[smitty1258]

Re: Continuance of skeg/prop damage

bump for prop choice help

 

[nlain]

Re: Continuance of skeg/prop damage

Think back to how the 21P prop worked, if it served you well then stay with that, if it did not then you want to look at other options, now for anyone here to really help we need to know how the 21P worked. My boat came with a 14X23 prop and it works well for me.

 

[smitty1258]

Re: Continuance of skeg/prop damage

the 21p worked ok, for just the 3 of us, but when we added people it seemed a bit more slugish, however would still get the job done, just took an experienced skier a lot of work to get out of the water.

 

[nlain]

Re: Continuance of skeg/prop damage

Did you reach wot rpm with the 21P? If so it probably would be what was speced on the boat new. They usually spec the prop to give wot rpm and then it works pretty good for everything. If you did not get wot rpm you were over propped and need to drop pitch. The general rule is about 200 rpm for every inch of pitch change. That gives something to work with.

 

[smitty1258]

Re: Continuance of skeg/prop damage

to be 100% honest im not even sure what WOT rpm is for my boat.

 

[nlain]

Re: Continuance of skeg/prop damage

Should be 4400 to 4800 rpm, my 2004 4.3L it rated at that rpm, I don't think yours would be any different. The manufacturers prop to the high side of the range or 4800. You are not going to run WOT that often but that is the range that you want to hit. As you change pitch below the current 21P you will be raising the WOT RPM and at some point could over rev the engine, just something to watch for, some people prop low to pull tubes, skiers, wakeboarders and just watch to top RPM. It sounds like you really need a place that will let you test run props to find what is best for your use. One for cruising and one for pulling.