4 blade prop on an I/O?

tn_guy212000 · Soul Rider Joined: 12 Jan 2003 Posts: 268

My friend has a bayliner with a 5.0 mercrusier in it and he was wondering if getting a 4 blade prop would help the pull and eliminate some of the washiness of the wake.. Does anyone have an I/O with a 4 blade on it? If so what brand and how much differnce did it make Question

squirrell · Outlaw Joined: 07 Feb 2003 Posts: 118 City: Pennsylvania

Do it. It will make the wake crisp along with a quicker shot out of the hole.

BIGMAC · Posted: Jun 15, 2003 5:35 pm Post subject:

How would it make the wake more crisp?

BIGMAC · Posted: Jun 15, 2003 5:36 pm Post subject:

Oh and it also depends abunch on what pitch the prop is.

gusthecat · Outlaw Joined: 28 May 2003 Posts: 183

Generally speaking, if you go to a 4 bladed prop (assuming that you stay very close to the diameter & pitch of the prop that you're already running) you will find more power out of the hole, the boat will plane up sooner/easier & have less cavitation. The down side is that you will loose some top end. If you were to go with a stainless 4 blade, then the benefits that I listed above will be even more pronounced, & you won't loose quite as much top end.

4 bladed props do produce different wakes than 3 bladed. I can't explain how (because I'm not entirely sure) but I've ridden behind the same boat with both & the 4 blade was much better - less foam/turbulence. Find a dealer that will let you demo a couple & see how you like it.

bluefish86 · Posted: Jun 16, 2003 11:37 am Post subject:

I went from a stock 3-blade on my merc 3L to a mercury Alpha 4. The hole shot is a lot better, and the wake is a lot less washy and better shaped. I lost about 3 mph top end. It costed about $250 canadian.

gusthecat, when I was at the dealer getting my new prop and asked about stainless, and he said the opposite of what you did. He said it would give me the same hole shot, lower top speed and cost three times as much. This is because any gain due to les flex would be lost because of all the extra spin weight. Plus, because stainless is more rigid, if you hit a rock it'll transfer the impact into the stern drive and damage it too, when an aluminium prop would only damage it self.

Leggester · Posted: Jun 16, 2003 12:31 pm Post subject:

Sorry, but your dealer does not know what he's talking about.

Alter Ego · Posted: Jun 16, 2003 2:27 pm Post subject:

4 blade will do a couple of things...
1)better hole shot
2)less top end (no biggie for boarding)
3)hold speed better

combine the four blade with a lower pitch and you will be able to hold a lot speed better and the wake will marginally look nicer (i didnt notice too much difference between 3 and 4 on my searay)

gusthecat · Outlaw Joined: 28 May 2003 Posts: 183

I was talking about stainless 4-blade vs. regular 4-blade (apples for apples). If your dealer says that a stainless version of the same prop will lower your top speed, then (generally speaking) he's wrong. He knows your boat better than I do, so in your case it could be true. The part about transferring forces is true, though, so some thought as to where you boat & how likely hitting a rock will be would be a good thing. If you demo the stainless & find that you like it, you may find a better price online. Check out http://www.propellersonline.com/. They've got a good reputation for an online vendor.

bluefish86 · Posted: Jun 16, 2003 4:52 pm Post subject:

Whatever, I'm just repeating what the dealer said. It might be because of the lower horse power on the boat (135hp), but then again he could also be dead wrong.

bkw4287 · Criminal Joined: 18 Mar 2003 Posts: 73 City: Central FL

I put a 4 blade 18 pitch comprop on my Sea Ray I/O. I have 1200 lbs in the boat and with 4 people it really struggled to get up with the 3 blade. With the 4 blade I've had 5 people and the 2 fat sacs almost full and it still gets out of the hole quickly. The wake is also larger even without the weight. I highly suggest getting a 4 blade.