Tempoarary Shaft Zincs

[Pgtjs]

I recently had a Kiwi Feathering Prop installed and it works very well especially in reverse. But it has a cone which precludes attachment of a cone zinc. As well it does not allow enough space between the end of the skeg shaft housing and the start of the prop hub. A regular collar zinc is about 1" thick and there is about 3/4 inch available. I have a couple of options and would appreciate any input/suggestions. One, I could shave the skeg fibreglass housing about 1/4" and then fit the collar zinc. There appears to be about 1/2" of skeg fibreglass protruding before the cutlass bearing is visible. Second, the Kiwi prop vendor has come up with an idea of cone extension and they are working on that but who knows how long? I put the boat back in the water rather than having it blocked up whilst this problem is solved. I will have to use a diver when we finally sort it out.

I checked with Kiwi and they say that the prop is all stainless and kevlar/ plastic and is not subject to electrolysis. I think the shaft is also stainless. But I feel nervous about not having zincs on the boat. I think the through hulls are all nylon and there is no other metal? What about the Rudder shaft?

So in the meantime, until I get one of the above, I am hanging a zinc over the side. I bought a "grouper zinc" at Westmarine but it only has 15" of wire line, supposedly galvanised steel, and I have attached it to the stern backstay for now. However I cant see that the backstay is connected to any earth so it may be useless. I was thinking of adding more wire line and leading it to the engine block which would mean about 25"between the zinc and the block. Would this be ineffective as it is too long? One marina observer says that the zinc needs to be near the next weakest metal and should be a short length from the grounding location. It should not be as far away as one of the mid ship shrouds. Am I correct in thinking that the shrouds connect to the boat's grounding system?

Until we get it sorted out, fellow 350 owners need to be cautious about the Kiwi props. I had one on my 320 and it was remarkably better in motoring boat speed and in straight line reversing. They are half the price of Max Props and much easier to maintain. Where we have rogue logs and difficult currents in marinas around here in the Pacific Northwest they are invaluable.

Thanks in anticipation for comments, cheers, Geoff (# 392).

[Tim April IV]

My shaft was (note the past tense) bronze. A little "incident" with a log last Christmas enabled a change to stainless.

I've read where some of the owners cut their zincs in half in order to fit in the very tight space available.

I wouldn't go without the protection of a zinc on your shaft. I was going to try to make an inappropriate joke about using protection........but it's not really all that funny.

Good Luck!

Tim Brogan
April IV C350 #68
Seattle

[william vanwagoner]

I think to be safe you need to have some sort of zinc on the prop or shaft. The stainless shaft is attached to other metals at the transmission and engine, and stainless can errode away. I have the standard 3-blade with a cone zinc, which fell off one time, and since have been having my diver cut a shaft zinc in half and put it on the shaft in case the cone should ever fall off again. I have noticed that the shaft zinc goes much faster than the cone zinc.

[Hans Grasman]

Bill,
I started using cone zincs 3 years ago and I have no problem loosing them. Before that I cut the donut zincs but that was a chore and they did not last as long. A diver cleans the bottom every 5 weeks and only replaces the cone about every 10 months.
In SW Florida you need to clean the bottom often.
The pencil zinc on the engine also lasts about 10 months.
Good to see a little activity on this site.

[Pgtjs]

Further to the lead posting above, I added a "shaft saver" coupling - West Marine part number 36848791 which is a Nylon type "shim" unit bolted between the shaft flange and the transmission flange. There are 4 bolts onto each flange ie 8 in total. This "saver" had the effect of extending the shaft length by 1" and creating enough space to fit a regular Donut Zinc on the shaft ahead of the Kiwi feathering prop. It has a second major advantage to us here in the Pacific Northwest where we are plagued by "dead head" logs in the water - if you hit one, the shaft saver is supposed to break before you do big damage to the shaft and ultimately to the transmission and the possibly the prop. I had such an event (bent the shaft etc) with my previous boat and they are not rare events at all around here.

I had the zinc checked after 6 months by a diver and it appears normal - perhaps 25% used. But an electrical engineer friend says I have made a mistake in that the shaft is not now earthed to the engine there being the nylon saver in the way. He thinks that leaves the shaft vulnerable despite the collar zinc. He said I should install a "shaft brush" outwards of the "saver" and tie it back to the engine block thus jumping over the nylon saver.

I asked the old sailor veterans at West Marine and they said they dont even sell shaft brushes any more - Marinco used to make them. They dont see why it would be necessary given the zinc collar in the shaft which is apparently working as it should. My shaft is stainless and the prop hub is stainless, so the zince is the softest metal unless there is something in the rudder cavity which is weaker.

So what do you all think I should do? In lieu of the shaft brush, I can tie two of the offset bolts on the saver unit together with electrical connectors and a short piece of 15 guage wire so could get the circuit reestablished from the shaft to the engine block. But is it necessary?

By the way, the West Marine part number is for a Yanmar 3YM 30 Engine - I have one in my C350 by special order when I ordered it so if any one wants to install a saver unit, WM can look up the exact unit for those with Universal engines. It may be the same but I doubt it.

Regards, Geoff, (Taeko IV) # 392.

[Tim April IV]

Geoff - I can't believe that you found room for a shaft saver coupling in your drivetrain! When I had the Dripless Shaft Seal upgrade/warranty work accomplished - which was done at the same time that I replaced a bent shaft, the mechanic that did the work had a heck of a time just getting enough room in that drivetrain to compress the bellows on the shaft seal - let alone take away another inch of clearance for the soft coupling.

When we initally bought the boat, the dealer mentioned that a Shaft Saver soft coupling might be nice and that he happened to have on "laying around", but when we went and looked at the factory installation of the new boat, we saw that no-way was there enough room for one.

Wonder how Catalina changed the installation to get more room between my #68 and your #392?