Prop size

[Toolsntoys]

I have been researching engine options for my 53 my. In doing so I was working with a reputable prop shop to determine what props would be suited for each desired power package. My Hatteras build sheet says that my boat came with 23x31 4 blade Michigan props. The prop guy can’t figure out why Hatteras used these and didn’t use a lager diameter. He is telling me that the boat should have 28” props. Thought?

 

[Boatsb]

Either theres a misprint or you have a prop that cant exist.

You should have a 28" diameter prop.

2" shafts do not fit 23" props. The diameter and hub size would make it outside of the norm.

I know theres a diameter minimum and maximum for each shaft size.

 

[KPTIM]

According to the Michigan Wheel technical catalog a 23 inch diameter wheels can have a 2" max prop shaft with no problem.

The survey report from my last survey says my props are 22 x 23 and I have 2" shafts.
I can see the 23 diameter wheel but that 31 pitch is bit much for a 53 with 8V71's.

I will check my build sheet tonight and also see what the spares are in the bilge.

 

[Toolsntoys]

Here is a pic of my build sheet

 

[dsharp]

Prop size will depend on the ratio of the reduction gears that were used.

 

[Boatsb]

Just replaced 2 4 blade 26 x 32 with beams. High speed (35 kt vessel)

Also spoke to the acme guys. Was told the minimum they did for our need was 24 or 26 inch on 2" shafts. It's all part of the hub size and stress based on hp.

Its a science now. Less gut and guessing. They make some nice CBC props.

I'm sure they are far more efficient than older designs.

 

[kelpy]

An you don't take those Veem''s and Acme's to the propeller blacksmith shops either.

 

[Boatsb]

F no.

 

[Boatsb]

Things of beauty

 

[Reefgeorge]

I don't know anything about prop sizes and Hatteras yachts in particular. That said, as stated it is more of a science these days and the prop shop makes a huge difference. I went through 4 of them before I found the holy grail of prop work. I have Acme and Veem and the Veems are a thing of beauty for sure. The diameter is limited by how close to the hull that the tips pass - closer equals more noise. The diameter is dictated by the engine loading so that WOT develops the correct RPM, say 2300. The number of blades is usually a tradeoff between faster (less blades) and smoother/quieter (more blades). You get rpm vs speed data and the WOT numbers for both sides and the distance to the hull and a quality shop/vendor can dial in what you need based on your goals. Not all manufacturers/prop series are equal. Some have cavitation problems for instance where a prop can be destroyed from the impact damage at the blade/hub interface. If you ever find a great prop shop that gets your wheels really dialed in, get them drilled for a propsmith or get a proper puller so that the yard doesn't beat the crap out of them and your transmission thrust bearings. Also make sure that they lap the tapers to the proper contact percentage as well.

George

 

[jim rosenthal]

Hard to believe the OEM would be 23 inches- that is tiny for a 53MY. And I have never seen a 23x31 wheel. 28 sounds more like it.

 

[Toolsntoys]

I’ll measure them this weekend to see if the build sheet is correct or not.

 

[micky]

My 43DC had 24 x 24 so a 53 should be way larger.

 

[saltshaker]

28" is the most common size for the 53MYs. I had a pair for sale a while back and the most common application was for the 53MYs. unless you have very shallow reduction gears.

 

[Pascal]

My Hatteras manual shows 28x28 with 8V71Ns 2:1 gears My spares were 28x26 4 blades nibrals which I had pitched down to 28x24 for the new 6CTAs also 2:1 but 2600rpm which I reach at 19.5kts.

 

[krush]

Blackdog props does the props for viking factory. He says none of the props come from the factory ready to go on a boat.

 

[Glory]

My 58YF is ideal with 28x 30 four blade,

23 can’t be right 43’ trawler had bigger props. Good luck

 

[SKYCHENEY]

With 465hp 6v92's, my 53 came with 28x32 2" shafts, 2:1 reduction. I ended up dropping pitch to 28 1/2" to get full loaded rpm to 2350.