FYI -- Shaft Brush

[baz]

FYI... This is a device I'm going to install tomorrow to hopefully reduce the rate my prop shaft zinc erodes.

Here's the sales pitch... 😉

"Shaft Brush
The "SHAFT BRUSH" installation completes the bonding system connection to the propeller shaft. It bypasses the high resistance of the gear box, due to the thin layer of oil on the gear surfaces, and gives you a higher level of protection for the propeller and shaft against damaging galvanic corrosion.

The "SHAFT BRUSH" is designed to accommodate installations in vessels with a 1" to 3-1/4" diameter shaft."

I attach several pictures of this Shaft Brush and will follow-up with additional pictures after I've installed it.

 

[baz]

The Shaft Brush was installed yesterday without too much trouble. I attach some pictures below.

1) The small length of chain was substituted with a plastic tie to allow easy removal and rotation of the Shaft Brush when engine maintenance performed. There's not too much space stern side of engine for feet placement etc.

2) The small length of green wire that came with the Shaft Brush kit was substituted with a longer 8 gauge wire to keep the resistance between stern mounted zinc and the Shaft Brush as low as possible -- besides, it also match the same gauge as used by the factory for bonding things in the engine bay. FYI -- the supplied green wire was not long enough to reach the zinc bolt on the starboard side of the transom.

3) The Shaft Brush was initially located mid point on the exposed prop shaft between the stuffing box and the engine shaft bearing housing. Question: what type of engine prop shaft bearing is employed in the Yanmar 150 HP? Is it a ball bearing type ?.

4) One question in my mind was... could the brush cause a `screaming noise' when underway with the prop shaft turning at high RPMs. Will no doubt find out later about this, but suspect any brush noise will be completely drowned out by normal engine noise.

5) After installation completed, I started the engine and nudged it into forward gear with the boat securely tied down in my slip. The reason for doing this was to see if the brush would gravitate/move to one end or the other of the exposed prop shaft. That is, would it move toward the stuffing box or the engine prop shaft bearing. As it happened, it moved toward and contacted the engine prop shaft bearing. The adjustment to make the brush stay put is accomplished by angling the brushes via their individual fastening screws. This was done a few times and at each time I observed how the brush moved until it did not move, and remained stationary at the mid point of the exposed prop shaft. I will occasional check this over time to see if the brush moves away from the mid point. Of course, when docked and hooked to shore power the important aspect is that the brush be in solid contact with the prop shaft.

6) The 8 gauge wire connectors were properly soldered at both ends to reduce resistance. The wire was easily routed and zipped-tied in place through the engine bay and back to the long bolt holding the stern zinc.

Now, over next 6 to 12 months I will record the stock prop shaft zinc erosion rate and replacement frequency to hopefully capitalize on my investment and time/effort for doing this. I will post back here over time. 🙂

I'm still pondering over the pros & cons for installing a Galvanic Isolator. I will be speaking/discussing this with my local guru Dick Troberg here in Edmonds (he lectures on boat electrics at the Edmonds Marina) who has an enormous wealth of knowledge in these matter.

 

[baz]

Curious to know if anyone else has installed a Prop Shaft Brush as I have done ? What are your +ive and/or -ive experiences ?

 

[jroyle]

I was going to install the same type brush system on my R29 but before I did I checked the continuity between the boat common ground (wire braid at engine) and the prop shaft. The ohmmeter indicated a short which means the brush would have been un-needed

 

[baz]

I will check mine also.

Something in my Marina is eating my prop shaft zinc like crazy!

 

[abcandjrc]

I was going to install the same type brush system on my R29 but before I did I checked the continuity between the boat common ground (wire braid at engine) and the prop shaft. The ohmmeter indicated a short which means the brush would have been un-needed

Which should be the case in almost every installalation. That stuff is all bolted together and hence well-bonded unless specific efforts are made to do otherwise.

 

[baz]

I was going to install the same type brush system on my R29 but before I did I checked the continuity between the boat common ground (wire braid at engine) and the prop shaft. The ohmmeter indicated a short which means the brush would have been un-needed

Yes--- but I've connected the brush to my below water-line stern mounted zinc. This should aid the prop shaft's end zinc protection capability or at least reduce the erosion of the prop shaft's end zinc some. Time will tell if this works for me.

It appears to me that the prop shaft's end zinc is simply too small and inadequate for dealing with and for protecting all the metal in the propeller and the shaft itself.

If I do remove the prop shaft brush at a later point I would connect the below water-line stern mounted zinc to the wire braid at the engine or directly to the battery -ive pole.

 

[baz]

Finally....

1) I will connect the shaft brush to the boat's bonding system via 8 gauge wire.

2) I will be installing a NewMar 30amp (Model NMR GI-30) Galvanic Isolator and use crimper for making the wire butt connections. I will bypass the FAILSAFE models as there's little chance IMO for encountering lightening strikes in the PNW.

I mean to say, all new Bayliners these days all come with Galvanic Isolators installed. 😉

 

[Andrew Custis]

The fail safe model is meant for random failure. If your isolator happens to fail not allowing the ground to pass through the isolator, how will you know? The only way to tell is taking your volt meter and measuring continuity. Galvanic isolators are not yet a perfect thing. This is why they are not required for installation from the manufacturer and most likely never will be.

PS: There are many differences with boats you purchase these days. If we are going to start comparing boats, at least give us the courtesy to compare apples to apples. 😉

 

[RProffer]

I don't know anything about galvanic isolators or failsafe isolators. I just started reading up on them. Here is a link that makes a good case for failsafe http://qualitymarineservices.net/Galvanic Isolator Article - D.Rifkin 10-25-06.pdf

 

[Andrew Custis]

Thanks for posting that. This is the exact reason I suggest the fail safe models. Without a monitored system, the average person would never know his ground was non functional due to the galvanic isolator.

ABYC has the largest impact on boat builders today with their influence to install the right equipment the "right" way to keep boating safe. After attending multiple ABYC and corrosion seminars each one of them mentioned the DANGER of installing Galvanic Isolators and were "NOT" keen on installing these. Pro Mariner is one of the first that I know of to make the fail safe model. Until this point, I would have only recommended the install of a galvanic isolator to someone that understood the possible danger of losing a grounding point and also done the training to make sure they knew how to test and monitor this.

 

[baz]

The fail safe model is meant for random failure. If your isolator happens to fail not allowing the ground to pass through the isolator, how will you know? The only way to tell is taking your volt meter and measuring continuity. Galvanic isolators are not yet a perfect thing. This is why they are not required for installation from the manufacturer and most likely never will be.

PS: There are many differences with boats you purchase these days. If we are going to start comparing boats, at least give us the courtesy to compare apples to apples. 😉

Thanks Andrew... My choice for a non FAILSAFE model is based purely on advice given to me by local electrical guru person with over 40 years of experience with boat electrics and who presents classes on boat electrics in our Seattle area. He was quite emphatic about not needing a FAILSAFE model for the PNW area. I do understand your position about FAILSAFE and will reconsider...

I made the "Bayliner" comparison because I consider the Ranger Tug product to be a far superior product and of higher quality and wondered why Galvanic Isolators aren't stock. Your response clears that up for me. I in no way meant for the comment to be a -ive one wrt to Ranger Tugs.

I now understand why Ranger Tug does not install GIs given your position about it not being a standard and them not being "perfect".

Andrew... as always, I consider your advice to be important to me and top-notch. With this in mind I will order a ProMariner ProSafe FailSafe Galvanic Isolator - 30amp based on your responses here and the conversation we had last week. Thanks. 🙂

 

[baz]

I'm thinking of placing the GI where it's visible and easily installed and replaced if needed. The backside of the Shore power connector is accessible through the cubby hole behind the helm console. If I drill a small hole into the cubby hole directly forward of where the shore power connector is and made it large enough for two wires to pass through I can connect the ground wires to the GI that I mount on the outside of the cubby hole. This sure beats trying to find a place inside the cubby hole for the GI and having to stretch and wiggle my hands attaching things while trying to avoid disturbing stuff in the cubby hole which is crammed full of wires and stuff. 😉 How have others installed the GI ?

 

[RProffer]

Barry, A good crimp on the bonding wires does not always ensure a good electrical connection, especially below decks where the possibility of corrosion is high. If you want to ensure a good electrical connection, you might consider silver soldering the connection after you crimp it.

 

[HRowland]

I am installing a 30A Guest galvanic isolator on our R27. This is fail-safe and meets ABYC specs. I also plan to test it periodically. This is easy to do using the diode test function on a digital meter, instructions are provided in the manual.

http://www.marinco.com/product/30-amp-galvanic-isolator

I have had rapid zinc erosion at the marina. I started using a hanging zinc (from BoatZincs.com) mid summer and it was noticably thinner at the end of the season.

Howard

 

[trailertrawlerkismet]

Howard:

Have you successfully installed the 30A Guest galvanic isolator? Did you do it yourself and if so was it fairly straight forward?

Jim F

 

[baz]

Howard:

Have you successfully installed the 30A Guest galvanic isolator? Did you do it yourself and if so was it fairly straight forward?

Jim F

I will be installing my GI (ProMariner ProSafe FAILSAFE 30amp Galvanic Isolator) in about a weeks time and will post back here how it goes. I do intend to install it so it's visible and I have easy access to it.

 

[HRowland]

Howard:

Have you successfully installed the 30A Guest galvanic isolator? Did you do it yourself and if so was it fairly straight forward?

Jim F

Jim,
I plan to install it this weekend. I will take some pictures and post them. I was busy this past weekend cleaning, priming and bottom painting the trim tabs and bottom painting the hull. I am going to the marina tomorrow morning when they launch her after the winter layup. I want to get the isolator installed soon since I will be connected back to the dock power and want to preserve the zincs!
Howard

 

[baz]

My GI (ProMariner ProSafe FAILSAFE 30amp Galvanic Isolator) arrived while I was away from home this past week in Oregon. I must say it's physically larger than I anticipated from the online web site pictures. It measure overall 8" wide, 7" high and some 2.5" thick. I'm pretty sure it would not sit comfortably inside the cubby hole behind the helm console along with all the other cables and wires.

I suspect I will install it outside the cubby hole on starboard side of the cubby hole's drop down door for ease of accessibility and periodic testing for correct operation.

I will post pictures of the install later next week.

 

[HRowland]

I installed a Guest 30A failsafe galvanic isolator in the battery compartment of our R27 yesterday. The power cable from the AC inlet has a lot of slack, I was able to carefully trim the outer jacket to expose the 3 wires. I cut the Green ground wire and crimped on adhesive shrink insulated 10/12G 1/4" ring terminals. I used the inverter to power a heat gun to shrink the insulation on the terminals, I did not want to connect the shore power while the safety ground was disconnected. I had to reroute some of the heavy 12V and ground cables in the area so they would not chafe on the isolator. I removed the Engine battery during the process so I could get my right-angle drill in position.



Hopefully the zinc anodes last longer this year. "B" dock at Harbor Lights Marina was less than 1/2 filled last year. This year it will be over 80% occupied, a lot more boats sharing the dock power (and ground!)

Howard