Inboard prop bore reducers

[alk]

Has anyone used the nylon bushings, on inboard props? They are used in the event the props are sized wrong for the shafts. I have three blades on my Viking, 23x23, the bore is 1.5”. They are a bit dinged up, but before getting them tuned, I was looking into buying some four blades. New are too expensive. when looking for used I saw a nice clean set, correct diam and pitch, but the bore is 1.75”.

I always assumed that using a bore reducer would be a bad idea, leading to vibrations, or other performance issues as a result of the extra strain around the key. But talking to my prop guy yesterday, he says that as long as you use the right key, and install correctly, they work fine and no issues. Any opinions? Researching a bit more, I see that bronze bushings are also an option - but of course three times the price.

Nylon Bore Reducer NB13

Nylon Bore Reducer NB13 1-3/4" to 1-1/2"

www.generalpropeller.com

Anchor Bushings Bronze Propeller Bushing - 1-3/4" Bore to 1-1/2" Shaft (BB13)

Anchor Bushings 1-3/4'' prop bore to 1-1/2'' shaft size bore reducing bushings available in Bronze to reduce your propeller bore to fit onto a 1-1/2 inch shaft. Fits 1-3/4'' prop bores. Part # BB13.

propshopinc.com

 

[Bruce Herrington]

Maybe you'd have better luck getting an answer by posting in NBR?

I have no experience with reducers..

 

[alk]

Maybe you'd have better luck getting an answer by posting in NBR?

i guess I need to find a boating forum, or Facebook group

seems like a bad idea to wrap my shaft in a bushing, but the prop guy says it’s no problem - and I could basically pay for all of my other winter projects, and gas for the summer, with what I’d be saving over cost of new props with right size bore.

 

[PascalG]

Never used them… if was going to i would Go for the bronze bushing instead of nylon. I’d be concerned about the nylon getting crushed or damaged. The key has to be bigger to extend into the a lot in the prop hub.

I wonder if you can get a good fit which is critical when installing the prop. One of the reason I don’t like the idea of installing props in the water as if the prop isn’t seated correctly, it could crack the shaft. Been there done that spent 3 days searching and raising a 40 incher in 25’ of water…

If you run mostly at low RPM it s probably ok but if you always run at fast cruise…. I d try to find the right wheels. Pitch can be adjusted a little if needed

 

[alk]

I don’t think I would ever attempt to change the props in the water, except in an absolute emergency situation. Short hauls are cheap enough around here - and considering my history there is pretty much zero chance nothing would end up dropped - between the props, nuts, puller, wrench, pins, etc.

ill probably keep looking for right size used - but I have been looking since October, and so far these are only decent ones I’ve seen. the prop guy told me I have a somewhat unusual size to begin with, and especially when considering my 1.5 inch bore. The shop that has a new set of Acme’s tells me I will get a significant performance improvement over what is on there now - but last time I added a blade, albeit to another bronze Michigan wheel, the results were not all that dramatic. Anybody running an acme or similar nibril prop on a 40-45 foot boat? Did it make a difference?

 

[alk]

I never did find any props last winter, but just saw a pair on fb that are correct diameter, and bore size - only the pitch is a couple inches high. Any idea how much pitch can be removed from a prop? They are 23x23, bronze Michigan dyna quads. I am looking for 23x21. I can call my prop guy Monday, but wondering if these are workable?

 

[CaptCrunch]

We’re using a pair of bronze reducers on a set of props now we’re using for testing after my repower. Spend the money for the bronze