R21 EC Prop zinc gone, again

[jkurlanski]

At the end of the season last year I noticed the prop zinc was gone, hex bolt and all. Figuring I had not torqued it down enough when switching it out that June. So this year I just put a new zinc and hex bolt on and gave it an extra crank.
Two weeks ago I had to pull the boat to deal with a lobster line wrapped around the prop (Maine hazard) and noticed the zinc and bolt are gone again!
Am I missing a nut for that bolt? Am I missing something else? I have to pull her again this weekend and will slap another on there, but what am I missing? Arm strength? :lol:

 

[knotflying]

Are you using Locktite blue on the threads? I also have placed two pennies on two sides of the hex to make a very tight fit. Are you in a marina and plugged into power? You may have a voltage leak going on in the marina. A sacrificial zinc fish over the side may help as will a galvanic isolator. What is going on with your other zincs?

 

[captstu]

Lock tire is essential for zinc threads installed without a nylock nut. As the zinc sacrifices, the bolt gets loose and goes away. You can use hot glue if you prefer, just as good and easier to get off when renewing zinc.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[jkurlanski]

Are you using Locktite blue on the threads? I also have placed two pennies on two sides of the hex to make a very tight fit. Are you in a marina and plugged into power? You may have a voltage leak going on in the marina. A sacrificial zinc fish over the side may help as will a galvanic isolator. What is going on with your other zincs?

I did not use Locktite. That may help as could the pennies. No shore power and the other zincs seemed normal.

 

[baz]

Joe: Take a look at my R-21EC Zincs photo album to see how my R-21EC's prop zinc is installed. It shows the old one and a new one to replace it.

These are photos of my 2016 R-21EC zincs after being in on the dry for 4 months, then fresh water for 18 months and then in salt water for 2 months. My diver zinc inspector took these photos before and after the inspection with some of them being replaced and some things just being cleaned.

In particular the old prop zinc and the new one for how it's secured.

http://www.tugnuts.com/gallery2.php?g2_itemId=49047

 

[jkurlanski]

Thanks all.

Does anyone remember the correct size of the bolt? I know I just bought it this winter, but I seem to have forgotten to write it down!

 

[jkurlanski]

Factory call and answer noted here for when I need to look this up again:

Stainless Machine Bolt will do.
5/16"
1 1/4" long
18 thread count

Zinc is a 'C'

Of course, posting this also ensures that I'll never need it again. :lol:

 

[sheral]

Loc Tite works great and I even use it on my mooring shackles.

 

[Cutwater28GG]

how do you do this in the water with a diver :?

 

[knotflying]

how do you do this in the water with a diver :?

Try this one if underwater
LOCTITE® QuickTape® 249™
Threadlocking TapeThe one and only threadlockering a tape form. Thisr evolutionary medium strength threadlocking adhesive is removable with hand tools, and offers the same reliability as traditional LOCTITE® removable- grade threadlocking liquids. Convenient, durable package is a must for every toolbox. LOCTITE® QuickTape® 249™
is easy to apply and can be preapplied for future assembly

 

[jkurlanski]

And hurray for trailerable boats which make pulling for mid-season checks a snap! 🙂

 

[SGIDAVE]

Factory call and answer noted here for when I need to look this up again:

Stainless Machine Bolt will do.
5/16"
1 1/4" long
18 thread count

Zinc is a 'C'

Of course, posting this also ensures that I'll never need it again. :lol:

Hello JK,

Here is the ordering page for the Prop nut anode. Yes, you want the 'C' size. Toward the bottom of the page the bolts are sold separately, and they already have the thread locker on them. Alternatively you can buy the entire assembly as a kit to include the 'nut' that threads onto your prop shaft to which the anode attaches. Boatzincs.com is the bomb. They sell little packets of thread locker that works well. Remember to apply to the bolt's threads ahead of time and let it dry prior to using the bolt.

dave

 

[captstu]

Locktite is applied, allowed to dry, and can then be screwed in underwater.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[Rwnorton]

Elaborate more please on the use of Locktite. Do I understand that the first time Locktite is used, with the boat either in or out of the water, apply to bolt, let dry, and screw it in. The next time, assuming the boat is in the water and the job is being done by a diver, what needs to be done? The Posts suggest there is residual Locktite to be removed, with difficulty?

 

[knotflying]

I would carry an extra bolt with the locktite applied and dried or use the tape and have it ready to go when your guy comes. You can then prepare the removed bolt for the next change. I never had a need to remove any old Locktite after removing the bolt.

 

[Ilovemaui]

This thread makes me curious. I assume the R 21 EC comes with zinc installed from the factory. If so how often does it need to be changed on a boat moored in slat water?

 

[Stevan47]

Concur with all the above advice. For myself, I always use Loctite, plus either an internal or external tooth lock washer under the head of the socket bolt. I also check the bolt security whenever I am out of the water and on the trailer. Only had a loosening problem once. Kind regards, Stevan

 

[baz]

This thread makes me curious. I assume the R 21 EC comes with zinc installed from the factory. If so how often does it need to be changed on a boat moored in slat water?

Gosh.... it all depends.... 😱

Typically (in most cases) a zinc will deteriorate faster in salt water. An anode can either be zinc, aluminum or magnesium. Many have converted to always use aluminum these days.

Salt water combined with keeping a boat in a marina and connected to shore power will/can cause the zinc to deteriorate faster that when not connected to shore power. It all depends on how other boats in the marina and especially ons close by have their electrical system configured.

 

[Sea Turtle]

I have an R21EC that was delivered in May and has been on a mooring all season. I have a diver periodically clean the bottom of the boat as we get a fair amount of growth in Bristol RI. He noticed the prop zinc was loose when cleaning and also was questioning the use of a stainless steel washer on the bolt. Also from reading this post is looks like stainless steel for the bolt is also used. Is it normal for Stainless Steel to be used for zinc mounting? He is going to tighten the bolt on his next visit. Will be interesting to see if the bolt is tight and the loose condition is the result of zinc loss. Appreciate any comments on the use of stainless steel. Thanks...Bob