4 blade vs 3 blade prop

[imported_wildcat]

I only have one prop at the present on my 5.0L MPI 260hp/ Alpha 1 and it is a Mercury Vengeance SS 14x19 3-blade prop. This prop came with the new 2004 boat from SeaRay. It is fine, but I would like to have a spare stainless steel prop. I would like to stay with SS for damage protection. I am aware of dissimilar metal corrosion potential, but am only using boat in fresh water.<br /><br />It appears that I have narrowed it down to either another 3-blade Vengeance prop, which would match what I already have, or buy a 4-blade Mercury Vensura 14x19 prop. <br /><br />I have researched the Mercruiser site and find the 4-blade Vensura listed under the prop of choice for durability, handling, water sports, cruising and top end speed. I called Mercury to discuss, and they said the Vensura is new and they don't know enough about it to express feedback. Alot of help. He said that I should expect to lose top end speed going from 3 to 4 blades. Mercury basically told me to buy another Vengeance prop.<br /><br />However, Mercury publishes the Vensura (4-blade) on the website as better than the Vengeance (3-blade)at higher top end speed, handling, watersports and quick planning. The 3-blade is only rated as comparable to the 4-blade at durability and cruising.<br /><br />Does anyone have any recommendations for me, since I lack experience and Mercury has no suggestion?

 

[crazy charlie]

Re: 4 blade vs 3 blade prop

I went from 3 blade to 4 on my twin 5.0lx mercr and I was told that when going from 3 to 4 blade you must use a different size 4 blade to achieve the same results.I went from 141/2 x17 on 3 blade to 15x16 on 4 blade.I would recommend trying a much less expensive aluminum 4 blade to see how you like it.I got mine for about $110 each.I can reco someone that sells them on ebay and you can deal direct.Charlie

 

[SteveRay]

Re: 4 blade vs 3 blade prop

Interesting post.<br />I just got off the phone with a reputable prop dealer. He told me that the 4 blade would be great for water sports, hole shot, fuel economy, handling. However,he indicated that there would be a slight loss of top-end speed. He also indicated that it would be a night and day difference between 3 and blade. <br />I have a 3.0L which is not as big but I would imagine the physics would still apply.

 

[tommays]

Re: 4 blade vs 3 blade prop

all props are done by trail and error which if you have a local prop shop who will let you try different ones is allways the best bet <br /><br />if not merc also has a custom prop shop that will blue print a prop but its very costly to have done you could spend 600 to 800 dollars depending what they do<br /><br /> http://www.mercurymarine.com/mercury_racing_propellers2 <br /><br /> http://www.mercurymarine.com/everything_you_need_to_know_about_propellers5 <br /><br /><br />there are 4 chapters here that will let you no more than you want<br /><br />tommays

 

[Doug Durako]

Re: 4 blade vs 3 blade prop

4 blades--more metal to grab the water and shoot you out on take-off. 6 blades---dual prop setup------even better.<br /><br />At high rpm, however, more metal creates drag and turbulance.<br /><br />The dual props have the trailing prop basically spinning in the turbulance of the leading prop, really not doing much after the boat is on plane.

 

[wvit100]

Re: 4 blade vs 3 blade prop

I have a mecury high five prop on my boat, five blades. It really gets up on plane fast and pulls tubes and such with no problem. I lost about 5 or 6 mph but the boat still goes around 55 mph and I can really feel a difference in how smooth it runs in the water, the prop vibration is gone. I have really liked this prop and would get another one in a heartbeat.