prop and shaft anti-fouling

[Alan Wheeler]

I took mine back to the shop asking if they had a warrantee as they kep't corroding away. Flamin cheap metals. They must be made in China huh?:-)

[Alan Wheeler]

Yeah Fstbttms, I understand. It's that accent again huh? Hey, just so you are totaly in the know, I really have no issue with you or anyone commenting on anything I state. I have said before and I say again, I stand to be corrected. I have a lot of knowledge and experiance, but I would only be a fool if I thought I knew everything.

But??? Wheels?? Now I am disillusioned! I thought YOU were the font of all knowledge Oh, that's right, it's GORD

[delmarrey]

Originally Posted by hellosailor

See now, the way I figure it a REAL dummy would have said "I don't understand why these zincs don't work, I bought four last year and I stowed them in the galley cabinet and they all still look GREAT what's the problem?" <G>

I stow my in places I can't find and have to go out and buy more. I just found them last Sat.

Originally Posted by hellosailor

A zinc is supposed to fit tightly on the shaft, and I've found that in order to get them on snugly, I need to hold a maul on one side, then slap the other side with a heavy hammer to actually force them together tightly around the shaft. After that, the screws just secure them together, no great effort needed to tighten them down.

By any chance do you have metric shafts? They do make metric zinks. My 1"ers go on just fine using the screws.

BTW my shaft zinks only last about 3 months. The keel (lead) is the only other metal in the water, but bottom painted. My thruhulls are Marlon. I do, do a lot of motoring while in the water.

[SkiprJohn]

Aloha Delmarrey,
I got the post on the max distance from cutless to prop that Gord posted. It would mean that I could have about 1 1/4" from cutless to prop. I'll probably have a bit more than that because my engine/trans/shaft coupling will probably determine that I have 2" or more. The shaft and prop max speed would be about 1020 rpm so I just can't see that it would set up too much vibration if it were a little further aft of the bearing. Am I wrong in that assumption because I can do a bit of engine bed modification to have the engine a few more inches forward? I just got it hoisted aboard so I can still do some modification before tacking it down.
Thanks for watching out for me.
Kind Regards, JohnL

Originally Posted by delmarrey

John,
There shouldn't be enough room between the strut and prop to put an anode. And, you don't want one there anyway!!!

The distance between the two is suppose to be the same as the diameter of the prop shaft, plus or minus a tad. Any more causes viberation and wear. Any less impeads the flow of water thru the cutlass bearing.

[Alan Wheeler]

Scott, I think we all sit at Gords feet when it comes to knowledge.
Mate, there is only one thing I am really turely knowledgable on. "The more I learn, the more I realise I don't know".

[delmarrey]

Originally Posted by SkiprJohn

Aloha Delmarrey,
The shaft and prop max speed would be about 1020 rpm so I just can't see that it would set up too much vibration if it were a little further aft of the bearing. Am I wrong in that assumption because I can do a bit of engine bed modification to have the engine a few more inches forward?

I'm assuming you have an 1-1/4" shaft. 1020 is a pretty good speed. If you have a fixed prop I wouldn't worry too much but it would be better to have it just right. The max. recommened prop dia. to shaft dia is 15:1. the closer to the 15:1 ratio the more viberation (18-3/4" max dia.)

Would you be able to trim a little off the motor end of the shaft and still have enough for a full key?? But if you have the room to move the motor, I would do it.

And alignment is very important and finalized while sitting in the water. Wood boats are a bitch

regards....................................._/)

[SkiprJohn]

Aloha again Delmarrey,

We're closing in on a decision now.

My prop is a Gori folding 18x13 two blade so prop shaft size to prop is ok. I can add a bit of beef to the forward end of the engine bed to move the engine if I need to. There is plenty of room. Just some more work and time.

Were you suggesting just cutting off a couple inches on the forward end of the propshaft while its in place? I guess I could to that as an option but would have to check the key way to see if it is long enough?

Hey, I guess this is what makes boating fun? Wouldn't I rather be sailing?
It's been a sunny 83 degrees the last few days with light breezes.

Kind Regards,
JohnL

[Rick]

Last week I went to a commercial "Fish Expo" and found a booth advertising a product called PropSpeed (www.propspeedusa.com), a "running gear coating". They had a dummy shaft and prop treated with their 4-step system. The first "step" is what they call "profiling" and what you and I would call "cleaning". The second step is "surface praration", what you and I call sanding. The third step is called "primer" you and I call it "primer" also! The primer is some two component chemical that supposedly bonds to metals and privides a tie-coat to the topcoat that actually prevents the growth. Step 4 is the topcoat application which, when set, is tannish in appearance and feels like a rubbery plastic.

They claim that as long as the topcoat does not get physicaly damaged that growth will not adhere to the surface. The small kit is expensive, around 100 bucks or so, I believe.

Has anyone seen or tried this product who can attest to or debunk the claims?

[delmarrey]

Originally Posted by SkiprJohn

Aloha again Delmarrey,
Were you suggesting just cutting off a couple inches on the forward end of the propshaft while its in place? I guess I could do that as an option but would have to check the keyway to see if it is long enough?

Are you still in the water?????

The shaft would have to come out but as a Machinist that would be the easiest way for me. Rather then having to add to the eng bed. The keyway can always be extended if need be. I could do it right here in my shop in less then an hour. But your a long ways off to offer it to ya. But any machine shop could handle that.

If your still in the water, the eng bed extention might be the most ecomomical. Also, cutting off a couple inches, would that create any problems if you wanted to install a PSS (packingless seal system). On this boat, I know I had JUST enough room to get a PPS on mine without moving the motor. You don't want to ruin that option!!! For an 1-1/4" shaft, you would need 8" between the front of your stern tube to the back of the shaft coupler. When installed and compressed it would be 6-1/2" long.

Enjoy............................................. ..._/)

[delmarrey]

Originally Posted by Rick

They claim that as long as the topcoat does not get physicaly damaged that growth will not adhere to the surface.

Has anyone seen or tried this product who can attest to or debunk the claims?

http://www.propspeedusa.com/application.htm

It sounds a bit like a non-stick like whats used in frying pans but cured rather then applied with heat.

I wonder how it would hold up if it were to get chipped like when a prop hits a chunck of wood?

[SkiprJohn]

Aloha All,

Thanks for all your information and explanations. I'll be deciding Friday on what to do. I can remove the shaft and might do that and have it cut down. Thanks for the offer Delmarrey. It is a bit of a flight to come see you.

Everything is a matter of economy (can't have your cake and eat it too). I can add a bit to my engine bed and forward mount the engine. I can cut the prop shaft at the transmission end. Or, I can live with about a 4" surplus shaft after the cutlass bearing.

It would probably be best to pull the shaft and have it cut down but then I'll sacrifice the length needed to do a dripless thing.

Oh well. Decisions, decisions.

I'm still out of the water which makes the decisions a little easier.

Kind Regards, JohnL

Happy Thanksgiving!!!

[fstbttms]

Originally Posted by SkiprJohn

Everything is a matter of economy (can't have your cake and eat it too). I can add a bit to my engine bed and forward mount the engine. I can cut the prop shaft at the transmission end. Or, I can live with about a 4" surplus shaft after the cutlass bearing.

IMHO, you are not going to have any negative effects from a few extra inches of exposed shaft after the strut. This is a very common situation (whether by design or happenstance) that I see every day. I don't hear anybody complaining about excess wear or vibration. I think to go to any length to rectify the situation is making a mountain out of a molehill.

Just my $.02.

[hellosailor]

Rick, the "Propspeed" sounds like exactly what SOMEone should be able to come up with these days. The stopper so far has been that everyone claims they can't get something to bond well enough to hold on at engine speeds with sustained use. I figure that just means there aren't enough "coatings engineers" with an interest in sailboat props.<G>

SkiprJohn-
As you note, everything is a matter of economy and unless someone said "Yeah, we sell all our prop shaft by the piece, not by the foot" I would question whether the designer of your boat *wanted* the shaft that long. Sometimes an extra six inches of shaft allows the prop to get an inch deeper away from the hull, and if you close that up, every time a prop blade swings by the hull you will hear and feel it. I'm just guessing, but I suspect boat builders would spec the length of the prop shaft for the minimum length, which is minimum cost, that will do the job "properly". No pun intended.

I'm kinda reluctant to change things until I *know* they're wrong. Sometimes the guys who designed or built them, just have un-obvious reasons for the way they did things. (And sometimes, they just used whatever parts were at hand.<G>)

[SkiprJohn]

Aloha Hello,

I'm in a total rebuild. The engine used to have a v-drive and a different transmission. Now is straight in line. Many things have changed. I rebuilt the engine bed before the new transmission which is longer plus changing the prop so throughout the years things in the engine compartment have changed a great deal.
At any rate, if I want it according to spec now is the time to do the change.

The prop blade will come within 3 inches of the bottom of the hull. I don't think that will be to close?

Happy TD.

Kind Regards, JohnL