my prop is turning blue

[f_inscreenname]

What dose it mean when you get blue areas on your prop? I use a left hand bronze ocean racer (very small solid hub) 15 1/2 X 21 cupped prop on my Volvo 270 and I have noticed some blue areas on the blades. It is the same color blue as when you start to heat a piece off steel with a torch. They seem to go away after a day or two of sitting in the driveway. Do I have to much slippage or something going on? I have never noticed this on any other prop I have used. I even had a right hand 15 X 21 cupped prop made of the same material (bronze) but it looked like a standard prop for a Volvo 270 (large hub) on the boat and I never seen anything like that. When I changed over to this prop last year I did notice that I lost a couple MPH but with the left hand prop it steered a lot better then it did with the right. With the right at high speed you would have to yank on the steering wheel to get it to turn but with the left it was like having power steering. I thought the lost mph was from the prop having less torque just because I changed from right to left but now I starting to think the prop isn't hooking up right.<br /> If it matters WOT is 4700 rpm and I see it at least before I come back to the ramp.<br />

 

[tommays]

Re: my prop is turning blue

bronze will turn a blue\green color when it Corrodes kind of like copper water pipe<br /><br />tommays

 

[f_inscreenname]

Re: my prop is turning blue

Hummm........... then why do I only notice it after a run? Never in the driveway (after a day or so of sitting). Is running it causing more corrosion? If so why?

 

[tommays]

Re: my prop is turning blue

i dont no but i guess your in salt water and the exaust gasses do pass over it most bronze props are on shaft drives and never get any exaust<br /><br />i dont think its a big deal<br /><br />never see and outdrive with a bronze prop<br /><br />tommays

 

[f_inscreenname]

Re: my prop is turning blue

Running in upper Chesapeake bay. Brackish water at best. I also use thru hull exhaust. At “any” forward speed the exhaust tips are out of the water. <br /> Like you said “ i don't think its a big deal”. Me neither but like I said I lost a couple MPH when I changed over from my last prop. I thought it may not be hooking up right. Maybe to much slippage or something. <br /> I will soon be putting it away for the winter so now (and for the rest of the winter) is the time I start analyzing things to see if I can make things better for next year. When you are a speed boater every little bit helps.

 

[Northern Eclipse]

Re: my prop is turning blue

I'm trying to figure out how you went from a right hand prop to a left hand, to my knowledge a left or right prop referred to direction of rotation could you further explain. I once had a aluminum prop that became discoloured at the leading edges, it was due to cavitation.

 

[Dunaruna]

Re: my prop is turning blue

NE, Your knowledge is correct, it does refer to rotation. The VP270 can be easily changed from Left hand to right hand, all the change does is make reverse forward and forward reverse....or was that forward reverse and reverse forward - I can never remember <br /><br />Aldo

 

[Northern Eclipse]

Re: my prop is turning blue

Cool,can't do that do a merc.

 

[f_inscreenname]

Re: my prop is turning blue

No you can't. Makes it nice when you are looking for props on e-bay. I prefer a left (boat performs better) but a right will work OK.

 

[paulrfrancisco]

Re: my prop is turning blue

Could the prop be cavitating? this is known to cause deteriation to a prop over time, perhaps yours show that with a color change in its early stages...

 

[Scaaty]

Re: my prop is turning blue

Originally posted by Northern Eclipse:<br /> aluminum prop that became discoloured at the leading edges, it was due to cavitation.

My guess too...due to cavitation.