Propeller fouling, unconventional idea...

[Franziska]

Hi,



just thinking out aloud. Just had a controversial idea.

I do read very often that people have big issues with their props fouling and the various antifouling paints not working well on them in areas with a lot of growth.

Many boats stay for weeks afloat without moving.



How about a a safe quick release system for the propeller.

You leave the boat for a longer period?



Quick dive, slide the propeller off, slide a dummy hub on (to prevent fouling on the shafts where it sits.)
Go home and upon return reverse.



One could even task the hull cleaning diver with this.



Thoughts?



PS.
We have folding outboards, so don't have this problem.

[wrwakefield]

Franziska,

I have had success in the S Pacific in the [distant] past diving and installing a large [plastic] trash bag over the prop and drive shaft [zip-tying it in place on the shaft] when I planned to sit still for weeks on end. The zip-tie requires another dive to remove the bag; perhaps one could be designed with a trip line for removal without a 2nd dive.

Also, in case of an emergency departure situation, the thin plastic bag would likely shred enough to allow the prop to work- but I never tried this.

The bag over prop is a localized version of enveloping the entire underwater hull using a large tarp [securing the tarp edges above the waterline with lines to rails, etc.]- which also seems to work in calm conditions.

I have also seen floating versions of the tarp for smaller power boats in calm waters. They slide over one edge of the float with outboard up and stop when inside the tarp. The floating assembly I saw was secured to a dock.


In case any of this is of interest.

Cheers, Bill

[leecea]

Aren't most props taper fit? They typically take some effort to remove.

[sailorboy1]

Lot easier to just clean a prop while diving on it than it would be to remove/install.

I would want my boat in the water with the prop off and unable to move it.

[MicHughV]

I agree that removing a prop underwater is not as simple as it sounds.
There is a cotter pin that needs to be removed first...
Then two bolts.....
Most certainly it will require a prop puller to remove the prop.
Finally there is a square prop pin that needs to removed.
Any of the above can find a new home on ocean bottom.

And....if you have a maxprop or other type of feathering prop, removing these will require six hands.

The trash bag idea sounds like it has merit...maybe ??

[Franziska]

Originally Posted by leecea

Aren't most props taper fit? They typically take some effort to remove.

Hmmm, maybe the proposed quick release would need to account for that.


It was just a thought which had. I have no idea if it would work and I have no intention to manufacture something like this. Just curious if someone likes the idea.

[Franziska]

Originally Posted by MicHughV

I agree that removing a prop underwater is not as simple as it sounds.
There is a cotter pin that needs to be removed first...
Then two bolts.....
Most certainly it will require a prop puller to remove the prop.
Finally there is a square prop pin that needs to removed.
Any of the above can find a new home on ocean bottom.

And....if you have a maxprop or other type of feathering prop, removing these will require six hands.

The trash bag idea sounds like it has merit...maybe ??

The device would need to be some sort of quick release which probably has a fixed part which stays on the shafts and another on the prop hub and temporary protective hub.



I think this sort of system would perhaps be especially interesting for folks with folding and feathering features which are hard to clean, hard to assemble.


As mentioned it's just a quick idea.

[Franziska]

Originally Posted by sailorboy1

Lot easier to just clean a prop while diving on it than it would be to remove/install.

I would want my boat in the water with the prop off and unable to move it.

Note sure if you are in a marina with a lot of fouling. Than you do not really need the "move immediately" option.

[Franziska]

Originally Posted by wrwakefield

Franziska,

I have had success in the S Pacific in the [distant] past diving and installing a large [plastic] trash bag over the prop and drive shaft [zip-tying it in place on the shaft] when I planned to sit still for weeks on end. The zip-tie requires another dive to remove the bag; perhaps one could be designed with a trip line for removal without a 2nd dive.

Also, in case of an emergency departure situation, the thin plastic bag would likely shred enough to allow the prop to work- but I never tried this.

The bag over prop is a localized version of enveloping the entire underwater hull using a large tarp [securing the tarp edges above the waterline with lines to rails, etc.]- which also seems to work in calm conditions.

I have also seen floating versions of the tarp for smaller power boats in calm waters. They slide over one edge of the float with outboard up and stop when inside the tarp. The floating assembly I saw was secured to a dock.


In case any of this is of interest.

Cheers, Bill

Sounds like a simple solution. Much better if it works.



Still why are not all the folks constantly complaining here about fouled props use it?

[rslifkin]

Originally Posted by Franziska

Sounds like a simple solution. Much better if it works.



Still why are not all the folks constantly complaining here about fouled props use it?

Not everyone is in a location where jumping in the water where the boat is docked is safe or reasonable.

[sailorboy1]

Originally Posted by Franziska

Note sure if you are in a marina with a lot of fouling. Than you do not really need the "move immediately" option.

Yeah I never have been anywhere with a lot of fouling etc.

Wonder why I carried that Hooka system around with me.

You asked for input on your idea. If you just want people to go along you should have said. There is no way a prop/shaft fit will ever be "quick release" without also being loose.

Just dive down there, clean it, cover it with grease or put the bag over it.

IMO of course

[wrwakefield]

Originally Posted by Franziska

Sounds like a simple solution. Much better if it works.

Still why are not all the folks constantly complaining here about fouled props use it?

Good question. It was fairly common practice among cruisers where I was playing at the time- but only for those planning to stay put for weeks at a time.

It worked well if one sealed the bag tight [preventing water exchange and introduction of fresh live creatures…]

Others didn’t bother as they said since their antifouling paint [age or type] required them to scrape their bottom every few weeks anyway, the prop and shaft were no big deal in comparison.

I would still bag my prop in the cooler waters we now frequent, but it isn’t worth putting on a drysuit, etc, to me…. Instead, since we average 3-4 years between haul-outs, we take advantage of a tidal grid on occasion [~annually] to perform interim maintenance on the underwater portions of the boat.

[Added] Our prop treatment [Petit Barnacle Buster over-coated with Amercoat 214 smooth ablative paint] typically lasts 2+ years full time use [e.g., ±300 motoring hours/year] on average, so we typically only deal with some hard growth on the prop in years 3 & 4. And by then it is usually time to service the aluminum anodes too…

Oh the joys of maintaining a boat in salt and brackish waters…

Cheers, Bill

[Franziska]

Originally Posted by sailorboy1

Yeah I never have been anywhere with a lot of fouling etc.

Wonder why I carried that Hooka system around with me.

You asked for input on your idea. If you just want people to go along you should have said. There is no way a prop/shaft fit will ever be "quick release" without also being loose.

Just dive down there, clean it, cover it with grease or put the bag over it.

IMO of course

I'm not at all asking for a yeah great idea. It was just a thought after seeing all those repeated complaints if folks that their prop fouls and what a pain it is.



I like the bag idea, if it really works. I also get that one does not want to dive swim in some waters.



Maybe I did not express myself in the answer to you. All I wanted to convey that instant move is not always necessary when in a marina.

In an anchorage or on a permanent mooring that is surely more needed.



Peace & flowers.



Btw. We have folding outboards so, it's not even an issue we have.

[SailingHarmonie]

A prop that comes off easily, doesn’t fit right. It should be tight enough that the primary torque transmission occurs through friction. The key should be no more than a backup.

If it fits correctly, you need a puller to get it off the shaft taper.

The black bag works fine. It also shreds instantly if you spin the prop, although you obviously shouldn’t make that your plan.

We find the prop speed properly applied, lasts a bit over a year, and since it is a release type coating, the number of fouling critters really doesn’t matter. They just don’t stick.

[JPA Cate]

Using the bags does work. Even for months [ left it this way for 2 months for overseas travel]. The bags exclude new organisms from entering to foul the prop, and also cut down on the oxygen in the trapped water, so the environment around the prop is less life supportive.

As to why people don't do it more often, I really can't say. It's never been a secret. I think some might be deterred by not knowing how to set it up to be removed safely from the boat without diving it when you're ready to leave. (We rigged an uphaul line.) And of course, there are some anchorages where it would take a life or death kind of emergency for me to go in--just too foul with biologicals and heavy metals--or a known bull shark population. Lots of reasons to avoid diving some places.

We always used to wait for the near the top of the tide for prop cleaning, to ensure the cleanest water with the better visibility.

Ann