[torchlake99]

Hello

I have a 1999 35 Open with Cummins 6BTA's, 370HP per side.  Boat came with Federal Nibral 23x29 three blade props and I am considering going to Acme 24" 4 Blade Nibral CNC Machined Props. 

Does anyone have experience with these props?  

Happy New Year

Kent

[trit21]

Hello

I have a 1999 35 Open with Cummins 6BTA's, 370HP per side.  Boat came with Federal Nibral 23x29 three blade props and I am considering going to Acme 24" 4 Blade Nibral CNC Machined Props. 

Does anyone have experience with these props?  

Happy New Year

Kent

Why are you thinking of going to a 4 blade prop? The 3 blade props work well in that boat at cruise and around the dock. What are you looking to improve? I think Tiara did a great job in determining the correct prop for th 35 in both pitch/size/ and blade count. 

[torchlake99]

I dinged my port prop last summer in the North Channel and was lucky that I was able to run the boat back to home port. Thinking about pulling these off and using as a spare set.  Heard that the 4 blade can increase efficiency over the 3 blade.  If I am going to pick up a new set might be worth going with different design.......

[trit21]

I know several people that have tried to fit 4 blade prop on boats that originally came with 3 blade (but not on an Tiara 3500 open)and they all say the same thing, waste of money for one reason or another. Even though you will get more surface area with 4 blades, you will have to reduce pitch and there is an spot where that doesn't make props more efficient but produces more slip. I don't know where that is or if 4 blades on a 35 would be in that region but when I talked to my prop guy he mentioned he didn't think it would be worth the money to change over to 4 blades and I would  not be happy so I stayed at 3 blades for my main props and my second set. Besides, I don't think Tiara would put on 3 blade props if 4 blades were that much more efficient, do you? 

[Chris Burkard]

Here is my $.02 worth: (these comments are only valid for a Tiara 3500 Open, as vessels get heavier, longer, wider and higher, it is common to see 4, 5, 6 and even 7 bladed props)

4-Bladed props if done correctly (proper pitch, diameter, blade design and blade cup) will reduce time to plane the vessel, will reduce vibration and may or may not be more efficient at cruising speed, but most certainly you will lose some top end speed.

As mentioned above, you are adding surface area to the propeller by adding another blade, which adds more friction. In order to overcome the increased friction, the pitch of the prop must be reduced in order to maintain the engines proper RPM range. The extra surface area does reduce slippage (slippage is the difference between the theoretical distance traveled forward per rotation of the propeller and the actual distance traveled forward per revolution), but depending on the engine, size, windage (wind resistance created by fishing towers), beam of the vessel and most importantly the weight of the vessel it may or may not increase efficiency.

To make a long explanation as short as possible, if you normally operate your vessel at a medium load (full fuel, 4 passengers and about 500 lbs. of gear, I would stick with the factory 3-bladed props. If you have a Tuna or Marlin Tower and/or you tow a tender and/or you operate normally with 10 of your friends on board, a set of 4-bladed props may offer you some increased efficiency.

Does that make sense?

[RickT]

My 35 Express 370 Cummins came with  24 x 26 4 blade props. Since they will turn 3100 RPM's I know they are the right size. But probably not factory issued. They are smooth and efficient. Might be more efficient at cruise but probably lost a knot or two off top end. But the 35 Open is a little lighter boat.

[torchlake99]

Thanks folks,  my 3 blade props needed repair anyway from a ding last summer.  Decided to try the 4 blade and the dealer is going to repair the prop, no charge.  Will send info after boat gets into water this spring on the numbers.  I am not looking for more top end speed but more efficiency in the cruising range.  Will find out this year.  I do know technology in props has changed since the boat was constructed in 1999.  Will be a good experiment so compare the numbers vs the 3 blade this year.

[torchlake99]

Wanted to let you all know that the 4 blade props are on the boat and I like the change.  We gained close to or right on 1 to 2 mph at most all of the rpm's compared to the old props.  My friend who travels with us with his boat said he thought it lifted the stern slightly vs the  3 blade.  It does handle a little better in the marina also. My bottom line was I had to send the 3 blades out for repair, the new props were purchased and the repair was thrown in for free.  I now have a spare set of props should something happen when we are out on a trip.  Like the spare set on board.
Thanks for all who contributed and safe boating this season.
Kent

[Chris Burkard]

Glad to hear that the 4-bladed props worked out for you!

The 35 Open is about the smallest Tiara Open that would benefit from 4 bladed props, unless the boat was heavily modified from original in the way of a Tuna Tower or if you tow a large tender.

[sgmcquown]

I would like to know more about the 4 blade props, i believe they are more efficient. do you have the manufacturer and specs?