Plumbing question for off shore trip

Noah · August 19, 2025, 06:51:23 PM

Kevin— WOW!

waughoo · August 19, 2025, 11:20:49 PM

Damn Kevin?!? I had thought you hit a kelp field. What did you actually hit??!!?

scgunner · August 20, 2025, 06:31:42 AM

Alex,

I have no idea what I hit if indeed I hit anything at all. There is a lot of kelp in the water but I haven't seen any big kelp paddies. If I had hit a floating object that wouldn't explain the clogged raw water filter on the other hand I can't imagine any kind of kelp encounter breaking a blade off the prop. After 30+ years the blade may have simply departed the prop. In any case I'm in the market for a new prop, a 3 blade like CD sells seems to be the way to go.

krafty81 · August 21, 2025, 06:38:04 AM

At 2200 RPM and 6.5 kts I show 155 on my temp gauge. Should it be lower?

waughoo · August 21, 2025, 09:42:31 AM

Kevin,

It makes me wonder if you had a dezincifocation of the prop blade at its root where by it weakened and let free in a tangle of kelp.

I happen to have a campbell sailor prop and my only complaint is my own selection of pitch and diameter. If you get one from the guy that spec's them, let him provide you with the "typical" set up for your engine and boat details. I asked to have a bit less diameter to allow the engine to reach max rpm at full throttle and I now regret it as there is no reserve thrust above cruise.

Krafty,

The engine's thermostat is set to open at 165 so your 155 on the gauge at 6.5 and 2200rpm is perfect.

KWKloeber ‘84 C-30 #3573 · August 21, 2025, 11:01:50 AM

Quote from: krafty81 on August 21, 2025, 06:38:04 AMAt 2200 RPM and 6.5 kts I show 155 on my temp gauge. Should it be lower?

Understand that Teleflex states that the temperature gauge "is an indication and the reading can be +/– 15°F.

scgunner · August 21, 2025, 04:59:40 PM

Alex,

"Dezincifocation" I had to look that one up. From what I gathered it's a process that affects brass and since my prop was plastic I'd say it's unlikely that was the cause.

Krafty,

6.5 knots at 2200 rpm is very efficient what kind of prop do you have? For your temp 160 is good as long as it runs around there leave it alone.

krafty81 · August 22, 2025, 06:08:42 AM

Quote from: scgunner on August 21, 2025, 04:59:40 PMAlex,

"Dezincifocation" I had to look that one up. From what I gathered it's a process that affects brass and since my prop was plastic I'd say it's unlikely that was the cause.

Krafty,

6.5 knots at 2200 rpm is very efficient what kind of prop do you have? For your temp 160 is good as long as it runs around there leave it alone.

Not sure of the type of prop but it is a folding prop.

waughoo · August 22, 2025, 09:45:49 AM

Quote from: scgunner on August 21, 2025, 04:59:40 PMAlex,

"Dezincifocation" I had to look that one up. From what I gathered it's a process that affects brass and since my prop was plastic I'd say it's unlikely that was the cause.

I made an assumption and as one knows...

scgunner · August 22, 2025, 10:44:01 AM

Alex,

No worries I'm guilty of the same thing myself more times than I'm willing to admit.

krafty81 · August 27, 2025, 07:02:36 AM

Looked on my boat. Could not find a Y valve for direct discharge but I did find the valve after the macerator pump. Looks like I can open that, run the macerator, and empty out the tank that way.

scgunner · August 28, 2025, 06:14:45 AM

Krafty,

Apparently sometime between '86 and '07 the valve was eliminated they probably felt it had become redundant. While my boat came with one I have never used it I've just never seen the need.

Ron Hill · August 29, 2025, 01:46:19 PM

Kevin : I'm surprised that with a missing blade the prop shaft didn't "Shake Your Teeth Out" !!

A thought

scgunner · August 30, 2025, 06:41:03 AM

Ron,

There's not a thing about that incident that doesn't have me shaking my head! An initial large vibration followed by the motor starting to overheat. What can clog the raw water intake and knock a blade off a prop (even a plastic one)? Then after clearing the strainer and raising the RPM back up the vibration while definitely there became tolerable so we proceeded. Most amazing to me with one blade gone (didn't know it then) we could still make a steady 5.9 to 6.1 knots with an acceptable vibration. The only reason I can come up with for this is the plastic prop being much lighter than a metal one was swinging a lot less unbalanced weight in a circle. Another thing the packing gland got warmer (but not hot) than usual but cooled back down after a while, I figure that was due to extra friction created by the vibration. That happened mid channel so we had to motor (no wind) for two more hours, all things considered I'd say Top Gun performed exceptionally well.

Ron Hill · August 31, 2025, 01:03:46 PM

Kevin : Who knows what may have been caught in that Kelp???

If you go for a fixed blade prop, I'd find a prop shop that uses "PropScan" to set the blade pitch. It sets the pitch/twist at 3 or 4 (I forget) positions on each blade. Much better than a mallet forming each blade to a wooden block!

A thought