Replacement Rudder and possible upgrades?

[dougxn]

Say, I pulled my rudder off my 2015 R-27 inboard this afternoon and brought it to Tacoma Propellor to have it reconditioned. It looks like my ruder has experienced a severe amount of Electrolysis. I have contacted Ranger about how to get a replacement, but I thought I might check with fellow R-27 inboard people and see what they have experienced. FYI: Ranger Tugs (Fluid motions?) seems to have contracted out the parts to Marine Depot Direct and they are extremely. slow getting back to me.

Anyway, it seems likely that the rudders might be made by Marine Hardware, but I will wait to find out for sure and see if that is the only place to get one.

1 - Has anyone replaced their Rudder with anything but the stock model? If so what did you get and how is it working.
2 - I noted someone suggested putting a set of clam shell zincs on the rudder to make it last longer - a little late for my current rudder, but for the future sounds like a definite plan. If you did it, has anyone found a good spot that won't interfere with steering?
3 - I resume the rudder is bronze, another materials any would suggest?

Back to the prop. I notice a fair number of people have a spare - Is it worth it? At $2200 that is one expensive extra part

Has anyone changed out their prop and had better luck with a different model. The one I pulled off is a ACME 1118 17"x17". I know this question will probably get me some push back, but I cannot think how best to shelf it.

I bought a prop puller, acme 330SN - it worked like a charm. Actually the hardest part was getting it tight and lighted up to the shaft.

I plan to install a big zinc somewhere on the transom as that should also help and my boat has grounding back to the rudder - easy access.

Thanks for your insight in advance - dn

Pictures - https://photos.app.goo.gl/Ejn1FSmfxUYsMy1t5

 

[BB marine]

The rudder is a Marine Hardware part. I have purchased parts directly from them. The big question is why did the rudder get damaged as badly as it did? Unfortunately Fluid Motion did not do a good job for protection of electrolysis. They did bond the underwater metals but did not add any protection for them. The only anode was prop protection. When purchasing a Ranger or Cutwater there are a few additions that you want to do to help protect the metals under the water line. First devise you want to install is a Galvanic isolator if you plan to keep the shore power active when at the dock. This will help from ow voltage DC currents circulating between boats nearby your boat's underwater metals, via the marina’s common AC earthing conductor. The next thing to do inspect all bonding connections at underwater metals. Make sure that they are not daisy chained. Each bonding cable should go to a bonding block. There should be no more than 1ohm of resistance between the metal and the bonding block. A divers dream anode should be installed on the bottom of the boat. One bonding cable should be wired from the bonding block to the divers dream anode. Resistance checks between the divers dream and each bonded underwater metal. (1 ohm) Parts that are included thru hulls and the rudder, engine block. parts not included that should have individual anode protection. Prop and prop shaft, Trim tabs, thrusters should be protected by anodes and not bonded to the bonding block. Anode preferences have changed. It use to be that zinc anodes were the best for protection. Aluminum alloy anodes now are the preferred anode. The bottom line is make sure that they are not mixed. You don't want both aluminum and zinc to be used. I would not install an anode on the rudder. I would make sure that the bonding cable attached to the rudder arm has a good connection and continuity to the bonding block and a driver dream is used. To check, ohm meter lead divers dream and the other lead touching the rudder 1 ohm or less reading and the anode is protecting the rudder. The photo of the exhaust flange. First thing I would do is remove all the cheap 304 SS fasteners that Fluid Motion uses and install 316 SS fasteners. Run a bonding cable to one of the fasteners and take it to the common bonding block. You want to inspect all 12V wiring in the bilge. Confirm that all butt connectors are properly shrunk sealed and not laying in bilge water. This is another source of stray DC current that can damage the metals. All of these items should be done when the boat was built and then inspected by the vessel owner or service center to confirm all in good condition annually. If this is dome with regular anode inspections you will not have a rudder that looks like yours. The prop? I'm not a fan of having a 2000.00 prop laying in the bilge for an emergency. I am a fan of regular inspections and tuning of the prop. This is needed in your case. I'm also a fan of when tuning the prop making sure it is tuned to allow the powrplant to turn 150RPM above manufactures recommended WOT. Example: D3 Volvo Penta 200 hp @ 4000 rpm. If propped correctly when fully loaded the motor should turn 4150RPM. The ACME props are IMO well made props. Expensive but good! Good luck with your repairs.

 

[dougxn]

The rudder is a Marine Hardware part. I have purchased parts directly from them. The big question is why did the rudder get damaged as badly as it did? Unfortunately Fluid Motion did not do a good job for protection of electrolysis. They did bond the underwater metals but did not add any protection for them. The only anode was prop protection. When purchasing a Ranger or Cutwater there are a few additions that you want to do to help protect the metals under the water line. First devise you want to install is a Galvanic isolator if you plan to keep the shore power active when at the dock. This will help from ow voltage DC currents circulating between boats nearby your boat's underwater metals, via the marina’s common AC earthing conductor. The next thing to do inspect all bonding connections at underwater metals. Make sure that they are not daisy chained. Each bonding cable should go to a bonding block. There should be no more than 1ohm of resistance between the metal and the bonding block. A divers dream anode should be installed on the bottom of the boat. One bonding cable should be wired from the bonding block to the divers dream anode. Resistance checks between the divers dream and each bonded underwater metal. (1 ohm) Parts that are included thru hulls and the rudder, engine block. parts not included that should have individual anode protection. Prop and prop shaft, Trim tabs, thrusters should be protected by anodes and not bonded to the bonding block. Anode preferences have changed. It use to be that zinc anodes were the best for protection. Aluminum alloy anodes now are the preferred anode. The bottom line is make sure that they are not mixed. You don't want both aluminum and zinc to be used. I would not install an anode on the rudder. I would make sure that the bonding cable attached to the rudder arm has a good connection and continuity to the bonding block and a driver dream is used. To check, ohm meter lead divers dream and the other lead touching the rudder 1 ohm or less reading and the anode is protecting the rudder. The photo of the exhaust flange. First thing I would do is remove all the cheap 304 SS fasteners that Fluid Motion uses and install 316 SS fasteners. Run a bonding cable to one of the fasteners and take it to the common bonding block. You want to inspect all 12V wiring in the bilge. Confirm that all butt connectors are properly shrunk sealed and not laying in bilge water. This is another source of stray DC current that can damage the metals. All of these items should be done when the boat was built and then inspected by the vessel owner or service center to confirm all in good condition annually. If this is dome with regular anode inspections you will not have a rudder that looks like yours. The prop? I'm not a fan of having a 2000.00 prop laying in the bilge for an emergency. I am a fan of regular inspections and tuning of the prop. This is needed in your case. I'm also a fan of when tuning the prop making sure it is tuned to allow the powrplant to turn 150RPM above manufactures recommended WOT. Example: D3 Volvo Penta 200 hp @ 4000 rpm. If propped correctly when fully loaded the motor should turn 4150RPM. The ACME props are IMO well made props. Expensive but good! Good luck with your repairs.

Thanks so much for your detailed explanation and advice!

 

[Rode Trip]

I agree with everything Brian wrote above, but I don't believe it addresses your problem. That's not galvanic corrosion in the pictures, you have a stray current corrosion problem.

Maybe someone with a good eye can spot your electrical problem, but most likely you need someone knowledgeable with a silver/silver chloride reference electrode to test everything on the vessel until they find the source. You really, really don't want to put a new prop and rudder on there until you find the problem. That extreme damage you already suffered can happen again in a matter of a day or two. You also really need a close inspection of everything else tied into the bonding system.

 

[BB marine]

I agree with everything Brian wrote above, but I don't believe it addresses your problem. That's not galvanic corrosion in the pictures, you have a stray current corrosion problem.

I do agree that the damage seen could be caused by stray current which I mentioned in my post. Proper bonding, inspection of wiring, especially DC wiring in the bilge. One of the faults I have found in production boats is the use of marine butt connectors that are not properly shrunk and sealed. I had a good percentage of connecters in my C26 that were not sealed. I also found a number of unused circuits that were fused with 12V present, tie strapped, and bundled with no devise connected. So 12V dc available with an open ended butt connector sitting in the engine compartment, gunnel or bilge. All can be a source of stray current if it is in moisture. The galvanic isolator is also a devise used to block stray current from flowing to the boat. I look at the galvanic isolator as helping in both galvanic and stray currents. Blocks low voltage stray current and also creates a one way connection to shore power blocking the connection to other boats on the dock. This insures that the anodes installed on the boat are only protecting "The Boat"and not other boats in the marina. Anode saver plus blocks stray current.

The prop in my opinion does not have any corrosion it is just damaged from hitting ''hard water" I would not be that concerned about installing a newly repaired prop. Plus it is protected by an anode. The rudder was not. The other item that was not discussed about the rudder damage is cavitation. I do believe some of the damage is from corrosion be it galvanic or stray current. I also know that the Ranger and Cutwater designed hull with the prop pocket and somewhat close prop tip clearances to the bottom can cause cavitation to the rudder. This was discussed years ago. Curt (Red Raven) had to replace his rudder because it was damaged possibly worse than Doug's. At that time I had my Cutwater and had painted the rudder with two part epoxy and bottom paint. I did a 3 week trip and when I completed the trip the same area of the rudder was stripped of all paint and polished to a shined finish. This was from cavitation.

So I do agree that the damage Doug has may not be caused entirely from galvanic corrosion and could possibly be stray current corrosion. The troubleshooting is about the same. The fix will include protection with anodes, galvanic isolator along with electrical inspections and repairs if needed as noted in my last post. I also believe that cavitation could be the cause too. There is nothing you can do about that. It is in the design of the hull. In my case and Curt's case we discussed it was possibly from higher rpm running that caused the cavitation. Just another possible cause for that severe erosion found on the rudder.