Cleaning/Rehabing Perko Sea Strainers

[JohnV8r]

Guys,

I'm in the process of rehabing my Perko 493 sea strainers. I soaked them overnight in a salt & vinegar solution to deal with the amount of heavy patina. Is there anything more aggressive that I can use to get down to the actual bronze color.

In the photo below, you can see one of the tops I wire wheeled and scrubbed with a stainless steel scrubber pad. The other is just straight out of the salt & vinegar solution. Wire wheeling and scrubbing is a very time consuming PIA way to get this clean. Can I give the parts a bath in something more aggressive - maybe Muratic Acid - to get to a clean surface down to the bronze?

[Bruce]

A mild solution of muriatic in an open area will do the trick. Its what I always used.

[JohnV8r]

Awesome. Thank you!

[Yannis]

John,
I recently did that job too.
I submerged them into a bucket filled with 100% vinegar overnight.
Next day they were sparkling shiny like yours, no need for any scrubbing.
Here you can buy 4 lt containers with vinegar at the supermarket, probably destined for restaurants, at approx. €3-4.
Muriatic I'm unaware what it could be.

[Rawleigh]

Be careful as too much acid will make it appear red in color.

[JohnV8r]

I did the muriatic acid bath in a 15 gallon water to 1 gallon acid mixture yesterday. I did have a few spots look a little pink, particularly the rods that hold the tops and bottoms together. However, this is what they look like this morning after staying outside last night (pieces are in the same order as the picture above):



You can see the one that was cleaned with the wire wheel is still more clean, but it doesn't look as clean as it did. There are a couple of spots of petrified cork from the gaskets that I'm going to get my Dremel out and grind off. They're too small for the wire wheel's to get to and they need to come off to prevent gasket issues down the road. For reference sake, this is what the strainers looked like just before I pulled them from the boat:



In the end, I'm not concerned about how long they look shiny and bronze. I just want to minimize the corrosion and make sure I've arrested what corrosion I can. My port rudder post is my real concern and cleaning up the Perko strainers was a dress rehearsal for getting into this issue:



I couldn't really see the extent of the patina on this rudder post until I had the deck off and really saw it in a 360 degree view for the first time. I am concerned that my port rudder looks worse than my starboard as I think some of the patina is electrolysis driven corrosion. I'm hoping the rudder post corrosion is all external. I have not had any leakage from my rudder posts either, which I think would have happened if the surface the packing gland material pushes up against was pitted.

I'll know once I get them off.

[Tooeez]

I am sure you know already, but after everything is cleaned up be sure to redo all the bonding wires--the corrosion seems to travel up the wires from the terminals, so just redoing the ends isn't enough. It's a pretty easy job when the deck is up. A Dremel with a stainless steel wirewheel makes quick work of the studs on the bonding strip. I was lucky enough to get my boat from the original owner, who did next to nothing in the 8 years he owned it, so I got to see a lot of how the boat came from the factory. The bonding wire for the rudder posts is attached to one of the thru-hull bolts; a jumper wire is connected to that bolt and the tiller arm, so that the rudder is also protected. The wire flexes as the rudder turns, so the terminals break on a regular basis. I am sure 98% of owners never replaced the jumper, so subsequent owners never realize the steering system is not fully protected.

[JohnV8r]

Wow! That's great info on the rudder bonding. I had no idea. I'm actually redoing the entire bonding system and adding a galvanic isolator. However, I'm pretty sure there is no bonding on my tiller arms looking at pictures I have with the deck off.

[Tony Meola]

John

When I redid mine, I did not go the jumper wire route, I just bonded each fitting directly into the system. I believe jumper wires are questionable.

Also, when I did my rudders, I made the wire longer than needed then curled it. This way it expands and contracts as the rudder turns. Eliminates breaking the wire.

Actually long run bonding wire that does not have support should be curled. Simple enough to do. Just get a half inch piece of copper pipe or anything else round and wrap the wire around it and slide the wire off.

[JohnV8r]

Great advice. Thanks Tony! I am following Pete Fallon's advice and running #8 Green wire in place of the copper bands. My plan was to put terminal blocks inline at strategic locations to allow me to run the bonding wires to each piece of hardware individually.

[Pete Fallon]

JohnV8r,
Another method is to use a bead blaster or soda blast them, just be careful not to etch the stainless steel ball on the inside of the sea cocks, also check the condition of the rods and nuts that hold the sea strainers together, they might be badly worn from years of use. New rubber gaskets on the top of the strainer body is a must. Perko sells a rebuild kit with new sight glass(Plastic), rods, gaskets and nuts. On your rudder posts check to see that the opening has not elongated over time, judging by the looks of the post it might be time to invest in some new ones. The hard stainless steel posts against the softer bronze has a tendency to wear the inside of the posts and packing nuts and on the hull bottom they might be elongated, I had to replace mine after 36 years in the boat.
Pete Fallon

[Charlie J]

why not do away with the strainers
and install south bay strainers on the hull

[Pete Fallon]

JohnV8r,
I replaced my strainers in 2010 with slotted strainers on the hull bottom, it freed up the interior space between the engines for additional storage and an extra group 31 battery on a shelf out of the bilge. Also your not tempted to step on the top of each strainer when the engine boxes and the hatch between the motors are removed.
I went with the Groco hinged style 2-1/2" full flow intakes under each slotted strainer. I used 2-1/2" long #6 Phillips flathead thru bolts to install the external strainers and bonded each strainer with #8 green AWG marine grade wire. Pre- drill and caulk each thru bolt when installing the slotted covers.
The reason for the change over was, I used to fish a lot of weed lines for Mahi Mahi, Wahoo and Sailfish in South Florida, I found that I was always checking the round sight glasses for weeds and the sight glasses used to get very dirty and the cheap welds on the internal stainless steel wire basket handles were always breaking or getting stuck when trying to remove them. The Groco's were not cheap but I found it well worth the change over, also my mushroom style thru hulls were getting worn and pitted after almost 40 years in the boat. Good luck with what ever way you go.
Pete Fallon

[JohnV8r]

I'm thinking about adding the external strainers. My biggest concern - aside from the fact that I'm bleeding money on this project right now - is the potential for Northern California marina growth to clog the screens. The water is colder here, so we typically do quarterly hull cleanings with divers. I do dive my own boat from time to time with my scuba gear to clean the underwater light lenses before any evening SF Bay cruises. I'm always amazed at the amount of stuff that seems to like the light lenses. I'm sure I'm overthinking it, but it's the devil I know versus the devil I don't.

I'm probably going to bight the bullet and get the sea strainers. It's just one of those things where I have a solution that costs $0 versus an upgrade of another $700. The engine rebuilds are at 166% of the original quote and the mechanic isn't finished yet.

We'll see.

Thanks!

[Tooeez]

If you think about it, if the packing in the rudder post is doing its' job the rudder itself is electrically insulated from the post, hence the jumper. The coil in the wire is necessary--I wrap mine around a pencil, makes wire coil smaller and easier to install under that rudder shelf. The jumper is still going to break about once a year no matter what. I also did the terminal blocks at various locations--it gets the connections up out of the bilge, much easier to clean and maintain.
One last thought about the south bay vs. internal strainers: if something plugs up the internal strainer you lift a hatch and clear it. If something plugs an external strainer someone needs to go for a swim.

[Charlie J]

in all my years of running boats I have never had a problem with the south bay strainers or the groco as pete mentiond
getting clogged
not saying it cant happen

[Tony Meola]

If you think about it, if the packing in the rudder post is doing its' job the rudder itself is electrically insulated from the post, hence the jumper. The coil in the wire is necessary--I wrap mine around a pencil, makes wire coil smaller and easier to install under that rudder shelf. The jumper is still going to break about once a year no matter what. I also did the terminal blocks at various locations--it gets the connections up out of the bilge, much easier to clean and maintain.
One last thought about the south bay vs. internal strainers: if something plugs up the internal strainer you lift a hatch and clear it. If something plugs an external strainer someone needs to go for a swim.

My rudder post makes direct contact with the bearing at the top as well as the rudder stop. I bonded to both the stop and the bearing so I eliminated the jumper since the rudder post is also bonded directly.

If you don't have a rudder stop you should think about it. In the event something happens it keeps the rudder from dropping out.

[Tooeez]

I have a collar at the top of the rudder post, about 2 inches above the bearing, to keep the rudder from dropping out. I have never seen a south bay clog either, but I have seen barnacle growth cover almost all of the surface, allowing almost no water through, even though the rest of the hull was fairly clean.