Can You Change A Propellar While The Boat Is In The Water?

[cmcguinness]

Hi all,
I have a boat with a folding propellar on it (previous owner was into racing I'm guessing). I'd like to change back to the original propellar so it is better matched to the engine giving me a little more power while motoring. Is this possible while the boat is in the water or does it need to be out of the water to do this?
Thanks

[dwentworth]

Yes you can. Scuba or surface supplied air and a prop puller makes the job go much easier but it can be done with breath hold and a home made puller. Remember to use a tether for each tool as well as the prop.

[jhnhll]

There are several you tube videos that can be found. Some of them found by searching things like bottom jobs. Give you some good ideas


Sent from my iPhone using Cruisers Sailing Forum

[dlymn]

When my prop fell off reversing into a mooring, I paid a scuba diver 70 euros to find it and bolt it back on. He said that he did that job once or twice a week. So It should be no great problem with a pair of pliers (if there is a split pin), prop puller, spanner and block of wood to jam between the prop and the hull. Watch out for the key when you take the prop off.

[fstbttms]

Not only is it possible to swap out your prop underwater, there is typically never a reason to haul a boat for any prop work, be it fixed, feathering or folding.

https://m.youtube.com/watch?v=2q3ntQF_Csk

https://m.youtube.com/watch?v=y3WaOWestWQ

[Bill Balme]

I'm not a racer either, but I find it strange you'd want to replace the folding prop with a fixed one. Marginal improvement when powering forward, vs. significantly less drag in the water, and much better performance when going astern...
(IMHO)

[Scout 30]

I've done this a couple of times holding my breath. It's a bitch so I bought a Brownie Pressurized Snorkel that I found on Ebay. It's small, runs on 12 volt power & is great for boat maintenance. I also made a prop puller out of a large C clamp. Grind the screw end into a point to fit the end of the shaft & grind a radius into the top of the clamp to fit against the shaft. As previously noted, watch your key when you pull the prop. If you drop it you'll never find it.

[rwidman]

Originally Posted by fstbttms

Not only is it possible to swap out your prop underwater, there is typically never a reason to haul a boat for any prop work, be it fixed, feathering or folding.

What about all that lapping and marking the "experts" recommend? Not important?

[roygee]

you can, but not without getting it wet.

[apacit]

I've had the same concern. Our boat seems pretty slow under power. Worse if the prop isn't very clean. We also have a problem keeping zones on it. The last one sheared a screw. My dive guy didn't want to pull it. He said he didn't have the right size top puller and worried about loosing parts. I sure like the speed when sailing, but all to often we need to motor to get to the next anchorage or inlet. Good luck finding a solution.

[fstbttms]

Originally Posted by rwidman

What about all that lapping and marking the "experts" recommend? Not important?

Important? I couldn't say. Certainly it's not necessary. I do know that props are pulled and reinstalled all over the Bay Area every single day without any of that happening and without any consequences. In over 20 years in this business, I have never been asked about it by a customer.

[Cadence]

Originally Posted by cmcguinness

Hi all,
I have a boat with a folding propellar on it (previous owner was into racing I'm guessing). I'd like to change back to the original propellar so it is better matched to the engine giving me a little more power while motoring. Is this possible while the boat is in the water or does it need to be out of the water to do this?
Thanks

A shoal slip with a shallow hard bottom is the place to do it. The chance of dropping a key or prop. nut is pretty good so being able to find one is great. Keys are cheap nuts not so much.

[Cheechako]

You'll probably want a scuba tank or to have it done. Some of those older racing props that fold are terrible so you might see big improvement. If it's a more modern one maybe not.

[farmall.dude]

I've done this a time or two on powerboats though. Just be sure it has something to keep the nut on (cotter pin usually). The first one I replaced underwater didn't have a pin to begin with, so I didn't know it needed one. Even though it is twisted down pretty tight, there will always be a tiny bit of water between the nut and prop. Can't avoid it underwater! I think that was a factor in it dropping off! Expensive lesson learned. Also, if you're doing it in the water it is kind of difficult/awkward to get the proper leverage to torque that nut down tight.

[wesevans]

In most boats this is doable. You need to check to see if there is enough room between the shaft and rudder to remove the prop. If you have a folding prop there is probably sufficient room. Instead of a fixed prop you might consider a feathering prop such as the Maxi prop.