Prop replacement

Post your technical questions or solutions about your boat's hull, prop or rudder here.

Moderator: KenKrawford

Triumph
Posts: 236
Joined: Thu Nov 03, 2005 7:34 am
Location: Tampa, Fl

Re: Prop replacement

Post by Triumph » Mon Feb 11, 2019 9:29 pm

I don't know the answer to your question. I looked, and I don't see my notes about which props we tested. There were three, the third being the 14x10 and the winner. I do not believe they were pitched any more than the 14x10, probably less. The increase pitch over this could harm your transmission if it is beyond what is recommended. That's what you need to check out. Otherwise, it may be a good thing.

Bill
TRIUMPH

Outlander366
Posts: 1
Joined: Mon Jul 22, 2019 3:33 pm

Re: Prop replacement

Post by Outlander366 » Tue Jul 30, 2019 3:54 pm

Triumph wrote:
Sun Feb 10, 2019 6:35 pm
Yes, there has been a lot posted about the issue with the prop making noise at higher RPM and the boat not going into chop well with the original prop. The original prop was called a "sailor" prop by the manufacturer. It's blades were not as wide as a normal prop. About 3/4" more narrow. This is the problem. Too little prop for too much boat. You need wider blades on the prop. The one Catalina suggests works well. It's got a good pitch, and wide blades. I've been running on it now for years as have other C350 owners and this pretty much solves the issues you mention.

PS. I was the guy that did the test of props for Catalina when we were looking for the right prop.

Bill
s/v TRIUMPH
Hi, I'm the new owner of hull 366 and I'm just learning the handling of this Catalina 350. Coming into my slip that has a starboard finger pier is very exciting when I shift into reverse as well as leaving the slip, although I'm able to fend off a post on the port side to counter the prop walk.

Bill, I read that you tested the M 14x10 prop. My question is does this prop do anything to reduce prop walk or did it just work to solve a cavitation problem.

George
S/V Outlander

Triumph
Posts: 236
Joined: Thu Nov 03, 2005 7:34 am
Location: Tampa, Fl

Re: Prop replacement

Post by Triumph » Tue Jul 30, 2019 3:57 pm

Only addressed the cavitation issue.

Bill

Capt. Nini
Posts: 18
Joined: Tue Feb 27, 2007 11:38 pm
Location: Gatesville Tx

Re: Prop replacement

Post by Capt. Nini » Tue Jul 30, 2019 9:55 pm

Sorry it has taken me so long to furnish details of the EWOL Feathering prop that I purchased in December 2017. I have been battling health issues that prevented me from testing the prop.

See 5 December and 6 December post.

I have a 16” wheel set at 17* which equates to 9.2 inches.
Took the boat out yesterday conditions varied. In smooth water with 12 kits. head wind I achieved 6.5 kts. STW and 5.9-6.2 kts. SOG at 2400RPM.

Reverse power is as instantaneous as in forward. Prop walk is about like the fixed prop, not enough experience to tell for sure. Don’t have light wind feathered prop stats yet.

It is hard to quantify, but under sail in 12-15 kts. wind, I felt like I had better performance.

rjengelhart
Posts: 4
Joined: Sun Sep 08, 2019 9:55 pm

Re: Prop replacement

Post by rjengelhart » Mon Sep 23, 2019 8:03 am

Hi. Anybody using Gori props...2 or three blabed?

What sizes?

Thanks.

sargentef
Posts: 37
Joined: Tue Nov 01, 2016 6:33 pm

Re: Prop replacement

Post by sargentef » Mon Sep 30, 2019 7:59 am

We put a gori 3 blade on ,15x9. Great prop, no prop walk, 6.5 kt.@ 2300.

sargentef
Posts: 37
Joined: Tue Nov 01, 2016 6:33 pm

Re: Prop replacement

Post by sargentef » Mon Sep 30, 2019 8:00 am

However, our fuel consumption has gone up!

wolfe10
Posts: 363
Joined: Mon Dec 11, 2006 2:58 pm
Location: League City, Texas

Re: Prop replacement

Post by wolfe10 » Mon Sep 30, 2019 8:30 am

sargentef wrote:
Mon Sep 30, 2019 8:00 am
However, our fuel consumption has gone up!
Look at the exhaust. Any black smoke (indication of over-fueling)? Yes, being "over-proped (too much diameter/pitch/# of blades) can cause this.

If so back out of the throttle until the black smoke just goes away. If you can run just under "starting to give black smoke" are you are OK. If not, may need to reduce diameter/pitch.

On edit: Had a private message asking how being over-proped could cause black smoke. OK, if the throttle is at or close to WOT (Wide Open Throttle), it is fueling enough to run the engine several hundred RPM faster than you are able to obtain. BUT, you are not taking in enough air to burn that amount of fuel-- the engine is "breathing less". Think of the engine as an air pump into which fuel is injected-- every second time each piston goes down, it draws in air through the intake. Lower RPM= less air flow. So, too much fuel for the amount of air- smoke.
Brett Wolfe
C350 #180
"Vindaloo"
League City, TX

User avatar
TBOT422
Posts: 353
Joined: Sun Jun 26, 2011 5:36 pm
Location: Clearwater, FL

Re: Prop replacement

Post by TBOT422 » Sat Nov 02, 2019 9:11 am

I finally had the opportunity to do some testing over the last week. Bottom was freshly cleaned. Out of gear our governed WOT RPM is about 3100 to 3200 RPM. After motoring for most of the day, while running in gear at 2400 RPM, went to WOT. RPM instantly went to governed RPM. That implies the boat is under propped per Brett's procedure. Since we have hull #422, and the letter from Jerry Douglas implies that all hulls after 400 were supplied with the Michigan M Series 14x10 prop, I assume that is what we have. I'm not sure where to go from here. My main goal is to increase boat speed when under power. Any suggestions?
Gary & Janet
The Best of Times (Hull #422)

wolfe10
Posts: 363
Joined: Mon Dec 11, 2006 2:58 pm
Location: League City, Texas

Re: Prop replacement

Post by wolfe10 » Sat Nov 02, 2019 12:10 pm

Agree, you can use more prop.

What is your boat speed at 2,400 RPM smooth water? At WOT?
Brett Wolfe
C350 #180
"Vindaloo"
League City, TX

User avatar
TBOT422
Posts: 353
Joined: Sun Jun 26, 2011 5:36 pm
Location: Clearwater, FL

Re: Prop replacement

Post by TBOT422 » Sat Nov 02, 2019 1:28 pm

I've not done any accurate speed tests. My guess is that we average around 5 knots at 2400 RPM. Sometimes 5.5 sometimes 4.5 depending on tide. A really strong tide and we can see 6 knots, but also have times when we can't get 4.

I have no idea what top speed is at WOT as I've never ran at that speed long enough for the boat to accelerate to a fixed speed.

From what I am reading, the Flex-O-Fold 15x10 may be over-propped. But I don't understand if that is a problem if you never run near WOT. If you are slightly over-propped and keep RPM below the "black smoke overheating" threshold wouldn't you be achieving your best speed possible?

As long as you are under propped you cannot reach an optimal speed even at WOT. Correct? I assume that cruising at 2000 RPM at 6 knots is better on the engine than cruising at 2800 RPM to achieve 6 knots.

We have the Universal M-35B and Hurth transmission that I believe has a ratio of 1.88.
Gary & Janet
The Best of Times (Hull #422)

wolfe10
Posts: 363
Joined: Mon Dec 11, 2006 2:58 pm
Location: League City, Texas

Re: Prop replacement

Post by wolfe10 » Sat Nov 02, 2019 1:52 pm

When discussing props, please specify 2 or 3 blade-- BIG difference.

Yes, the the Flex-O-Fold 15x10 three blade is over-pitched. Good boat speed for RPM, but one has to be careful/be aware of smoke to not overload by trying for too high an RPM. Keeping engine running at its best (valves adjusted, clean air "filter", clean fuel and clean fuel filters, etc) helps.

Said another way, with a knowledgeable operator, an OK choice.

Would see if anyone is running a Flex-O-Fold 15x9 three blade and what their experience is with it.
Brett Wolfe
C350 #180
"Vindaloo"
League City, TX

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