Two questions - water pump and barnacle impact

Dec 29, 2017
124
Beneteau Oceanis 411 Baltimore
While the main water pump works fine, it’s very noisy. I’m wondering if any one has purchased a pump that has quiet operation?
Also, my propeller and shaft were encrusted with barnacles from this past season. Towards the end of the season I was having issues with getting the boat up to full speed, notably once I went beyond 2000 rpm the engine would quit. Any chance that the barnacles were causing the issue or should I be focused on mechanical issues, like the fuel pump lift? Additionally, anyone have a paint that they recommend for keeping barnacle growth down on prop and shaft?
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
anyone have a paint that they recommend for keeping barnacle growth down on prop and shaft?
Never paint your metal prop and shaft.
The metals must be exposed for Zinc galvanic Corrosion protection.

My prop and shaft stay clean, if used frequently.
______

I’m wondering if any one has purchased a pump that has quiet operation?
That depends on the "Ears" of the beholder.
Mine is noisy, but it happens in bursts, since water use is short lived.

Most water pumps are Positive Displacement pumps, so their noise depends the number of "pumping cylinders".
Mine has 3, the newest 4 cylinders, is a bit quieter
Jim...
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
Never paint your metal prop and shaft.
The metals must be exposed for Zinc galvanic Corrosion protection.

My prop and shaft stay clean, if used frequently.
I disagree (respectfully), and think that you both should read this Practical Sailor article: Propellor Paints Versus Barnacles - Practical Sailor
Personally, I used the Pettit Barnacle Barrier spray as an easy, cheap solution after consulting with both my yard and diver. I've not seen the results, but the diver is not complaining. You can top that with normal bottom paint, if you like. Like all underwater paint, prep is critical, so wire brushing, cleaning, etc. before you paint. Mask all shaft zincs, or they stop working (perhaps that is what Jim was referring to).
 
Last edited:
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
While the main water pump works fine, it’s very noisy. I’m wondering if any one has purchased a pump that has quiet operation?
When you say "main water pump", are you talking about the on-engine raw water pump for engine cooling? If so,
  • When was the last time you replaced the impeller? If the answer is "don't remember" or "not since the Obama administration", then do that before you start it again, and buy an extra couple impellers to keep on-board. Lots on this board about how often to change, cleaning out the broken blades from your heat exchanger, etc.
  • Did the noise change from the past when it was quiet? How can you hear a water pump over the noise of the diesel?
  • How do you know that it "works fine", or are you just assuming that it's not overheating so ...?
  • What brand water pump, and does it have a sketchy history (Sherman)? Perhaps the bearing is shot?
  • Is it leaking?
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
While the main water pump works fine, it’s very noisy. I’m wondering if any one has purchased a pump that has quiet operation?
Also, my propeller and shaft were encrusted with barnacles from this past season. Towards the end of the season I was having issues with getting the boat up to full speed, notably once I went beyond 2000 rpm the engine would quit. Any chance that the barnacles were causing the issue or should I be focused on mechanical issues, like the fuel pump lift? Additionally, anyone have a paint that they recommend for keeping barnacle growth down on prop and shaft?
If you mean the fresh water pump, I think it is typical that they make some noise. The pump in my RV makes the same noise as the one in my boat, and I have gotten used to the noise. You could insulate the compartment the pump is in to decrease the noise level.
The barnacles on the prop shaft would not cause the engine to quit. I would look for an issue with the fuel, maybe clogged fuel filters.
The paints mentioned work well for me to keep the barnacle growth down on prop and shaft. I have tried leaving them bare, but the paint definitely works better. You might need to do a trial and error approach in your area.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Zincs will NOT protect a painted metal.

Why?
Zinc is more noble than typical prop and shafts, and painting is an insulator.

You better read closely the Practical Sailor article.

Painting with metal based paints, is possible...
But...
Consider the amount of metal in the paint versus just running your propeller cruising.

This is the best, but only if you take your boat out of water each season.
Also see their instructions...
"Do not apply anti-fouling paint over Zinc Coat"

That was my point about galvanic corrosion.
Jim...
 
Dec 29, 2017
124
Beneteau Oceanis 411 Baltimore
As always, thanks to the community for the input.
KappyKaplan - you are not kidding on barnacle growth - it was a mess this year. As to water pumps, I was speaking about the one that feeds the sinks. I got an email from Overtons advertising a new quieter model - must be one of those 4 cylinder versions.
I changed both of the fuel filters when the issue started, but it did not resolve. The mechanic on our dock thought it sounded like the fuel pump lift, but when I saw the barnacle growth was wondering if that was causing the problem.
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Pettit came out with a new prop paint and bottom paint. Not cheap but claims to be better than their Barnacle paint. I’ve tried several methods with success and some not too successful, but moving up and down the coast puts different environments around my prop and shaft. Nothing is foolproof, just better.
 
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rukidn

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Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
If your water pump is mounted to starboard under sink, that panel acts like a giant speaker cone. I replaced my pump, hoping for quieter, but no success. A 3/8" aluminum plate bolted to the panel with soft washers, and pump mounted to the plate significantly quieted things down. a little mass changes the natural frequency of the "speaker". /Ed
 
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Jan 24, 2017
666
Hunter 34 Toms River Nj
full disclosure I do not advocate this practice Nor do I do this anymore due to epa and osha regulations.
Many many many years ago i used axel grease. Worked amazingly, never once had a single barnacle. Now I sail mostly in very brackish water and don’t have any issues. I would used a good out drive paint that is not ablative. I don’t believe that zincs would not protect against galvanic action provided they are installed on clean bare metal.
 
Dec 29, 2017
124
Beneteau Oceanis 411 Baltimore
If your water pump is mounted to starboard under sink, that panel acts like a giant speaker cone. I replaced my pump, hoping for quieter, but no success. A 3/8" aluminum plate bolted to the panel with soft washers, and pump mounted to the plate significantly quieted things down. a little mass changes the natural frequency of the "speaker". /Ed
Ed - any chance that you could send a picture of your install once back on the boat?
 

DArcy

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Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
You could try some ant-vibration mounts for your noisy water pump. If you can feel the "buzz" from the pump in the nearby cabinets this may help and they are fairly cheap. There are stud mount style which should easily replace thru-bolts. You need to select the appropriate size for the mass of the pump. If you have a 4 pound pump, the mounts should accommodate 1 lb each (assuming 4 mounting screws)

 
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rukidn

.
Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
Sorry for the delay. Here is the pic of the pump with the sub-plate and additional damping pads. If I did it again, I'd use a larger, heavier plate as the mass is critical to damping the sound. The cabinet panel really resonates.

I also purchased an accumulator which will help with small water draws without the pump running. I'll install after launch.
 

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