Spare Prop

[Propnut]

I thought a spare prop would be nice to have on my single screw trawler, and thought a used one would be easy to find. Boy was I wrong.
A 26 x 20 LH 1.75” bore three blade propeller is nonexistent.
So if I were to damage my prop I’m done until I can acquire a new one .
So I’m thinking about biting the bullet and go ahead and order a new prop.
Question is, which prop manufacturer would you order from?? What material?? Any suggestions from the experts here?

 

[OldDan1943]

I thought a spare prop would be nice to have on my single screw trawler, and thought a used one would be easy to find. Boy was I wrong.
A 26 x 20 LH 1.75” bore three blade propeller is nonexistent.
So if I were to damage my prop I’m done until I can acquire a new one .
So I’m thinking about biting the bullet and go ahead and order a new prop.
Question is, which prop manufacturer would you order from?? What material?? Any suggestions from the experts here?

I am not an expert!!!!!
I suggest Bronze although some folk will swear by stainless steel.
Are you going to stow it on the boat? Secure so it is so it is not a problem in bad weather
Check with the nearest prop shop. They might have one laying in the shop or give you a lead. If not, internet search.

It's not necessary to buy a new prop. A good rehab prop that passes NDT tests. Dont forget to buy a new shaft nut and key.
Are you going to buy wheel puller?

 

[O C Diver]

I thought a spare prop would be nice to have on my single screw trawler, and thought a used one would be easy to find. Boy was I wrong.
A 26 x 20 LH 1.75” bore three blade propeller is nonexistent.
So if I were to damage my prop I’m done until I can acquire a new one .
So I’m thinking about biting the bullet and go ahead and order a new prop.
Question is, which prop manufacturer would you order from?? What material?? Any suggestions from the experts here?

If you're sure that the one you have is perfect, order the same one from the same manufacturer. A good prop shop can tell you exactly what you have, whether it's been re-pitched, and if it's current state matches the markings.

There is a black art involving witchcraft and sacrifices to get the perfect propeller for your application. Switching from perfect usually guarantees disappointment.

Ted

 

[High Wire]

I thought a spare prop would be nice to have on my single screw trawler, and thought a used one would be easy to find. Boy was I wrong.
A 26 x 20 LH 1.75” bore three blade propeller is nonexistent.
So if I were to damage my prop I’m done until I can acquire a new one .
So I’m thinking about biting the bullet and go ahead and order a new prop.
Question is, which prop manufacturer would you order from?? What material?? Any suggestions from the experts here?

You can't go too far wrong with Michigan Wheel, bronze, 3 blade. It's not a high performance application.
If it will only be a spare, 25 inch diameter will probably be close enough.

 

[SoWhat]

I purchased from deepblueyachtsupply. Not inexpensive but they had better price than anyone else and more importantly had want I wanted in stock.

Call them to check stock. Be prepared to juggle pitch and diameter and number of blades a bit.

 

[Arc]

If your prop is right , then get the exact match. If you don’t and switch props you will have to pay haulout to switch back.

 

[kchace]

Deep Blue Yacht Supply has your exact size prop in 3 blade.

 

[backinblue]

Trying to understand why you would need to carry a spare unless you are cruising full time and in remote locations. I see Deep Blue has your prop in stock for $2200. But a spare is not something that you can easily swap out if needed, so why not wait till you know you need one before buying? Also, unless you completely trash your prop, it may be repairable. Either way you need to plan a haulout, so what's the need to carry a spare?

 

[jleonard]

I always carried a spare just in case. Also had a prop puller, wrenches, spare keys, nuts, and cotter pins.
Also had minimal dive gear in case I needed to replace it myself.

 

[jgwinks]

My 1973 Concorde came from the factory with a spare set, it's on the original sales order as "standard equipment". Unheard of. Anyway the previous owner had the the spares in storage and one of them was pretty badly bent up, so the they came in real handy to him. I had it repaired. A prop can be changed in the water of you have or borrow a prop puller. Not really easy but doable, so not absolutely necessary to haul out. That assumes the shaft didn't get damaged too.

 

[backinblue]

I always carried a spare just in case. Also had a prop puller, wrenches, spare keys, nuts, and cotter pins.
Also had minimal dive gear in case I needed to replace it myself.

I get it. nice to have spares for replacement, but a prop is not something you can immediately replace underway, so I'm not sure a spare saves much time if you can order when/if needed. I know I am generalizng, but just questioning the logic. I guess it could be relaced by a diver, not sure how practical that is.
Also, how often does a single screw boat need a new prop?

 

[Comodave]

If you are cruising and damage a prop having a spare means that you can continue the cruise with minimal disruption. If you have to wait for a new prop or wait to have the damaged prop repaired it could take several weeks, especially with today’s supply chain issues. Also it could mean being hauled twice or having a diver come out twice. Spare prop(s) are really nice to have.

 

[Bacchus]

My vote also for a spare. I can find a place for a short haul / prop replacement much quicker than waiting for a new one or damage to be repaired.
I was fortunate to find an exact match for $250 and about $500 in rebuild... all in about 1/3 of new.

 

[OldDan1943]

I always carried a spare just in case. Also had a prop puller, wrenches, spare keys, nuts, and cotter pins.
Also had minimal dive gear in case I needed to replace it myself.

might consider a spare shaft too

 

[Comodave]

A lot of boats don’t have a place to store a spare shaft, but it is nice to have if you can store it.

 

[Northern Spy]

You can shop around and purchase a used prop and have it repitched to what you need without a rush. This will allow one to continue using your boat if/when the need arrives. Otherwise you are held to the cost and schedule of the prop shop to repair or replace.

How often does a boat need a new prop? The koan answer would be: Why do prop shops exist?

Note: I'm currently purchasing a used prop from a prop shop to make my boat LH instead of RH, so I can back to Stbd.

 

[OldDan1943]

Get them "tuned". There used to be 5 levels, I have mind to the third stage.

Google 'tuning a boat propeller'

 

[Rufus]

My spare is a 3-blade Michigan 24x22...the twin boat is propped correctly with 24x20's. I've occasionally wondered just how much pitch can be removed by a good shop. Anyone know? Although, probably not a big deal to run it as is in a pinch.

 

[Northern Spy]

My spare is a 3-blade Michigan 24x22...the twin boat is propped correctly with 24x20's. I've occasionally wondered just how much pitch can be removed by a good shop. Anyone know? Although, probably not a big deal to run it as is in a pinch.

2" of pitch on 24" isn't all that much. I've had that much changed on a 19" prop.

 

[Comodave]

I had the props on our last boat tuned up and had them take off .5” of pitch. The pitch wasn’t the big deal on the tuning but rather getting all the blades to the same pitch. We had 4 blade 24x24 on that boat. On each prop there was one blade that was way out of pitch, over an inch. They tuned them up an took off the .5” pitch on each. Cost $800 for each prop. But it took away a lot of vibration that we had. Well worth it.

 

[Rufus]

2" of pitch on 24" isn't all that much. I've had that much changed on a 19" prop.

Thanks

 

[High Wire]

If you are cruising and damage a prop having a spare means that you can continue the cruise with minimal disruption. If you have to wait for a new prop or wait to have the damaged prop repaired it could take several weeks, especially with today’s supply chain issues. Also it could mean being hauled twice or having a diver come out twice. Spare prop(s) are really nice to have.

Agree 100%. Short haul for an hour and you are on your way. Set up a repair of the damaged one at your convenience.

 

[Takoradi]

I was fortunate in buying my Uniflite 42 from the original owner that I think must have been a belt-and-suspender kind of guy. On board and perfectly stored are 2 spare props, shafts, and prop puller. Like you, I also keep dive gear aboard.

Tak

 

[Greg S]

… I've occasionally wondered just how much pitch can be removed by a good shop. Anyone know? ...

I recently asked a friend who has owned/operated a local prop shop for decades.
He said a prop shop could add or subtract up to three inches of pitch. It depends on a few things to do with the prop too, of course.
The prop I was asking about was under 20” diameter.

 

[koliver]

Note: I'm currently purchasing a used prop from a prop shop to make my boat LH instead of RH, so I can back to Stbd.

What?
Are you going to run in reverse to go fwd and in fwd to go back? Are you getting repowered with an engine that goes the other direction?
You started this thread drift, so please fill us in.

 

[koliver]

I recently asked a friend who has owned/operated a local prop shop for decades.
He said a prop shop could add or subtract up to three inches of pitch. It depends on a few things to do with the prop too, of course.
The prop I was asking about was under 20” diameter.

I did 4" 22 years ago and am still very happy with the outcome.
Started with 19x13, increased pitch to 17. Job done by Osborne, reputed to be the best around. First set done and installed, decreased cruising rpm by ~700, reduced fuel consumption 5 to 10%, so I happily took the spare set in for the same pitch change. All good 21 years in.

 

[Northern Spy]

What?

Are you going to run in reverse to go fwd and in fwd to go back? Are you getting repowered with an engine that goes the other direction?

You started this thread drift, so please fill us in.

Yes. It is a small mechanical clutch Volvo MS transmission, which is a rebranded ZF, which is actually a Hurth. So I lose a bit of thermal efficiency with the idler gear turning. All I need to do is reroute the Kobelt control cable to make it push-pull instead of pull-push and have it run in the B position for my new forward turning LH.

Unfortunately, when the used LH prop was getting repitched, it opened up a casting defect on the root of the third blade so I am back on the hunt for one.

My original prop is an Osborne. They have the best motto, "Screwing boaters since 1935".

 

[backinblue]

Yes. It is a small mechanical clutch Volvo MS transmission, which is a rebranded ZF, which is actually a Hurth. So I lose a bit of thermal efficiency with the idler gear turning. All I need to do is reroute the Kobelt control cable to make it push-pull instead of pull-push and have it run in the B position for my new forward turning LH.

Unfortunately, when the used LH prop was getting repitched, it opened up a casting defect on the root of the third blade so I am back on the hunt for one.

My original prop is an Osborne. They have the best motto, "Screwing boaters since 1935".

Awesome motto!

 

[Hawkshaw1]

Trying to understand why you would need to carry a spare unless you are cruising full time and in remote locations. I see Deep Blue has your prop in stock for $2200. But a spare is not something that you can easily swap out if needed, so why not wait till you know you need one before buying? Also, unless you completely trash your prop, it may be repairable. Either way, you need to plan a haulout, so what's the need to carry a spare?

I am far from an expert but my boat came with a spare prop and a diver installed it and I sent the old, slightly damaged prop out for repair. The damage looked minimal but the new prop was much smoother. It seems like a good idea to have a spare to me.

 

[jgwinks]

For those of us who's boats came with spares, they're awfully nice to have. They can be changed in the water and you're on your way in a couple hours. Whether that justifies the expense of buying up front is another matter. Personal choice. If you're going to be cruising remote areas that's more of an argument.