Anodes education for me please

serpa4

Well-known member
Joined
Jun 20, 2020
Messages
286
Fluid Motion Model
R-23 (Sterndrive)
Hull Identification Number
FMLC3051D818
Vessel Name
DayLo
MMSI Number
368173760
So, I just agreed to buy a 2018 C30 Sedan with the LE package!!!! Yeah.
Anyway, the boat is 2000 miles away. I went for a test run and all was good. Then hired a surveyor and his report came back very good with minor issues that can be fixed pretty easily.
One was the Anodes (zinc???). I'll primarily use in salt water, but 30% in fresh water lakes.
I cannot go take delivery of the boat and trailer till January, but would like to take the anodes with me since the boat will be on a trailer.
The rear anode on the transom needs to be replaced asap.
There are two, one on each trim tab.
Anyone have a specific brand and part number so I can order online and take them from New Mexico home to the boat in Florida? I'd like to use the boat while I'm in Florida for a few days to shake it down.
Are there other anodes on the boat? The surveyor said some boats have them in the thrusters.
Thanks for any help, part numbers, or web links.
 
I have a large zinc on the prop shaft behind the prop, one on each of the trim tabs and small ones on both the front and rear thrusters (tips of the small propellers). I also have 2 zincs that are located on the engine - raw water side at the heat exchanger and further rear in the same raw water path. If you have the volvo manual it should show you approximately where these are located. I don't really have a brand preference. My boat is moored in salt water all year and, at least where I'm at, they need to be replaced roughly every 6 months. It's pretty obvious when they start to deteriorate - the get pitted badly and if left long enough may partially or totally disappear.

Since I'm having some work done on my boat at the moment I'm taking the opportunity to add two additional and larger zincs, one on the top side of each of my trim tabs.

Better the 'burn' zincs than the metal that holds your boat together.
 
I get my zincs from boatzincs.com Great service and fair pricing. You will need to decide if you are going with aluminum or zinc for the anode material. Best not to mix but sometimes impossible not to.
Here’s a good article explaining the differences of metals:

https://www.fisheriessupply.com/underst ... ial-anodes

In my R25 Classic I have zincs in the following locations:
One each on the thrusters
A set on each trim tab
A big plate on the transom
Two inside my Yanmar 4BY2-150 engine (your Volvo may be different)
One on the tip of the prop shaft aft of the prop
Some folks (not me) have a set mounted to the rudder

PS: When you identify the right part numbers for your boat I’d buy at least two sets of everything. If you keep your boat in the water full time they will go pretty fast. I have heard of folks in the PNW in “hot” marinas going through four sets a year.
 
"PS: When you identify the right part numbers for your boat I’d buy at least two sets of everything."

Ya, that is what I hope to find from this post is a few part numbers since I don't have the boat in front of me to measure.

In the immediate future, I really need the anode on the rear transom with the two bolts going through it.
 
The Bennett trim tabs use this zinc: R-3A Rudder Aluminum Anode - 3-3/4" Dia. or the R-3 in zinc from boatzincs.com
If you have SidePower thrusters the zinc is the SM31180A Side-Power Aluminum Anode. Don’t think zinc anodes are available for the Side Power thrusters any longer.
 
scross":25faf90r said:
I have heard of folks in the PNW in “hot” marinas going through four sets a year.

I can vouch for that!
 
Size anodes can be found here viewtopic.php?f=20&t=15150#p100115

Shaft Dia.1-3⁄4". PROP ANODE SIZE
3-3/4IN Trim TAB anode
4x9 X 1/2 IN. Divers dream anode
(Imtra) Mfg# SM31180A part number of thruster

Fluid Motion uses Zinc anodes which work in salt water only

I use ALUMINUM ALLOY Fresh water/ Brackish/ Saltwater

Zinc as a sacrificial anode is becoming "old school" It works and has worked for years.Zinc is not favorable to our environment. The Aluminum alloy anode works as well and in many cases better than the zinc anode. Do some research on the subject to make a decision as to what will work best for your use.

There are plenty of places to purchase all the anodes needed for the C30. Use the sizes posted above for a reference. .
 
Number ONE reason for anode loss is keeping a boat on Shore power in 'hot" Marinas. Your boat becomes Ground for every other boat around....causing anodes to work overtime. Almost impossible to avoid when on Shore power anywhere in busy boating waters
Unless you NEED to be on Shore power 24/7 (running the AC, Refig., etc.), many advise just hooking it up 1-2 days before you depart. FWIW: My '19 zincs are original, 2 Seasons old -still over 50%.
 
If you are picking the boat up in FL then most any marine repair shop will have the anodes in stock. They are common items in all cases.

The thrusters may, or may not, have anodes as there is a change happening in the industry to resin gear legs and assemblies that mitigates the need for an anode. There are two types for these, cones and donuts. Once you see your thrusters you should be able to tell.

You might also reach out to the surveyor and get his ideas on where you could find them as I am guessing he was local to the boat.
 
JonR":24jraf8d said:
...
Since I'm having some work done on my boat at the moment I'm taking the opportunity to add two additional and larger zincs, one on the top side of each of my trim tabs.
...

Jon,

Be aware that unless you have modified them the trim tabs are not bonded and thus additional anodes on the trim tabs will not help protect anything on the boat besides the trim tabs. If you are looking for more protection for all the bonded underwater metals I recommend adding anodes to the swim grid struts below the water line (they should be bonded), adding a rudder zinc, or adding a transom zinc (mini divers dream).

If you are just trying to add more protection to the trim tabs then you can ignore this.

Curt
 
Not sure if the Cutwaters come with a galvanic isolator from the factory. If not, you should consider one if you will be on shore power often. Will reduce the need to change you anodes as often. They are not cheap but are easy to install. I plan on installing mine on my R29 over the holidays. - Franco


Sent from my iPhone using Tapatalk
 
The clam shell ones for anodes....
Doesn't 1/2 the anode above and 1/2 below the plate mess up the water flow on the bottom of the trim tab?
 
BB marine":2k85yrrq said:
Size anodes can be found here viewtopic.php?f=20&t=15150#p100115

Shaft Dia.1-3⁄4". PROP ANODE SIZE
3-3/4IN Trim TAB anode
4x9 X 1/2 IN. Divers dream anode
(Imtra) Mfg# SM31180A part number of thruster

Fluid Motion uses Zinc anodes which work in salt water only

I use ALUMINUM ALLOY Fresh water/ Brackish/ Saltwater

Zinc as a sacrificial anode is becoming "old school" It works and has worked for years.Zinc is not favorable to our environment. The Aluminum alloy anode works as well and in many cases better than the zinc anode. Do some research on the subject to make a decision as to what will work best for your use.

There are plenty of places to purchase all the anodes needed for the C30. Use the sizes posted above for a reference. .
Thanks. I just started reading about the aluminum alloy ones. They seem the best of all worlds.
I"ll definitely check a local place in Fl for them and just pick up a few of each. I live in New Mexico, marine stores are = 0.
 
I have to kick in as aluminum is best for salt and brackish water, but magnesium is best for fresh water. And I agree with zinc anodes being old school. I decided some time back to move away from zinc anodes. It's either aluminum or magnesium. And boatzincs.com has a wide selection of sizes and types at a good price.
 
ohioan55":1jcaw2tr said:
I have to kick in as aluminum is best for salt and brackish water, but magnesium is best for fresh water. And I agree with zinc anodes being old school. I decided some time back to move away from zinc anodes. It's either aluminum or magnesium. And boatzincs.com has a wide selection of sizes and types at a good price.

Ya, boatzincs has a lot. I'll have to get the right one off the back of the boat under the swim platform when I get to FL. Then start ordering on line.
 
Diver's Dream or whatever brand.

Mini: 6" x 4". 1-1/4" to 4-1/4" slot spacing with 3/8" bolt size.
Normal: 12" x 6". 2-1/4" to 9" center-to-center bolt slots with 1/2 bolt size.

Any preference or can you use a larger one in that the slot spacing is larger and bolt hole is larger.
I don't have the boat in front of me to measure.

Can you mix Zinc and Aluminum?
From the survey, the Hull one is almost gone/needs replacement. Trim tabs one is more dissolved than the other, but all are zinc. I'd like to go aluminum. I.e. I assume thrusters (if it has them) are also zinc.
Update: Guess you cannot mix al and zinc. The Aluminum anode will be used to protect the zinc and will erode faster. I guess you can mix, just wasting money.
 
According to the spreadsheet for the C30, it says, "As of 2017 thrusters are Lewmar"
And the sheet does not list anodes for lewmar. Only the (Imtra) Mfg# SM31180A.

If my boat is a 2018, do the Lewmar not use anodes?
 
A call or e-mail to the factory customer service technicians will give you all your answers. I assume you have the Hull number. The ranger tug parts department can give you the exact numbers of all anodes used. If you elect to use Aluminum anodes you can use the zinc anode numbers and cross reference them to aluminum.

You should not use different anode materials if they are bonded. Example: the thruster housings are not bonded to the boats bonding. Imtra recommends the use of Aluminum anodes to protect the housings. Aluminum is installed there. The Bennett Trim tabs should not be bonded to the boats ground. The anodes mounted to the trim tab planes are only protecting the trim tab planes. Many Ranger and Cutwater owners use zinc anodes to protect the rest of the under water hardware. Think of this as three separate boats being protected.. I personally do not like using different anode materials. It is not advisable to mix. You should not mix anodes that are attached or connected to metals that are with-in the scope of the boats bonding.
 
Lots of really good information discussed in this thread. Thanks.....
 
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