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Bob,
I'm needing your expert advice on props, please, sir. I broke a shaft and lost a prop. The props were 18x18.5 3 blade bronze with a medium cup. I got the 315 Yanmars with 1.5 ratio gears. The boat performed great coming out of the hole and plenty of power for blowing through waves. top speed was 40 mph at 3800 rpms fully loaded. Problem is, the props were reworked several times and there's no way to buy one new to match the one that I have left. We can't find a brand on the prop. If you have time, would you please give me some advice?
Thanks. Bob
John.

ps I can use 1 3/8 or 1 1/2 bore props.

I can use 1 3/8 or 1 1/2 bore props.

John,

Does that mean that you're using 1 3/8" diameter shafts? If so, you really need to be running 1 1/2" Aqua 22...

yes I agree 315 yanmars need 1.5 shafts
1 3/8 would explain the broken shaft

We hit something in the water going 30 knots and the shaft broke just behind the strut. You guys are right, but for now, I just need to get back in the water asap...the wahoo are thick and we're fishing every weather permiting chance. I'll upgrade everything when there's more $ in the boat fund. I'm having a shaft built this week, and, I have a throw down pair of props that i'll use until I come up with something else.
Thanks.

John.

I'll keep a look out for the Fed Ex guy with a package of Wahoo delivered to my door. I know you wouldn't forget your ole pal Mark?!

John

You better get a set of prop nuts with that shaft. I sent you the only ones I had.

Tony

john do you know the transmission gear ratio? normally 2 to 1 with those engines and if so you are running a prop. dia. to small to take advantage of diesel fuel economy however if you are happy with what you have and you have a nearby prop shop they will put the other side prop on the "comparator" not really a computer but most nautical people call it that so you put on computer and a prop shop will match exactly except in counter rotation.i agree with the captain should be 1 1/2" aquanet 22 with only 1" space between rear edge of struct and forward edge of prop. hub on shaft for high speed running like that.you could ship prop to me and i copy ,build and ship both back both shipping cost would be crazy.

Call Baumann. Have them pick up your remaining prop from Noe's. They can match it. Same material, same pitch.

Mark,
I'll swap you wahoo for chesse curds...deal?
Bob.
I'm real happy with the 1.5 gears...35 plus knots at wot, and, 1.7 mpg at 28 knots. I'm going to use the 1 3/8 shafts for now and will upgrade in the future. It seems like you guys have alot more load on your shats with the 315 or 330 hp engines with 2 to 1 gears and 21" or 22" wheels than I have with 1.5 shats with 18" x 18" wheels.The problem is, my existing prop has been cut down, repitched, recupped, and, I thought it might be hard to match..and, ther's no brand name stamped into it. Even though I'm happy with the performance that I had, if there's a way to enhance things, than now would be the time to do it. I know that you are the prop professor, so I thought you might have time to help, but, I don't want to impose.
Thanks everyone.
John.
ps I messed up on my first post...I need 1 1/2 bore wheels and will use shims untill the shafts are upgraded...I'm using them now and have no vibration or any other issues.

Hyena Love wrote:Call Baumann. Have them pick up your remaining prop from Noe's. They can match it. Same material, same pitch.

I'll second Ernestos recommendation. Don't use MIke Hood, I still want to peel his eyelids off over my first set of props.

If you dumping money for a new shaft...maybe consider just doing the one side, cause that "used" shaft is going to be a loser when you try to get rid of it.
Pull strut, machine and install 1-1/2" cutlass. Stuffing box and coupler are not big ticket items, might even be able to open what you have....your already looking for a 1-1/2 bored wheel.
My .02 and gets you motivated to do the other side sooner then later.


I mention as my friend kept snapping the shafts on his 47 Buddy Davis...mostly when docking. We were giving at just over cost...but he was always running the boat up and down the coast, and although he had heavy pockets...he liked to keep them heavy. Finally one let go offshore on a snotty day when backing down on a fish...it was a long haul in bad weather back to Hyanis, he was then hit with a ridiculous number to get boat back up and running again. When he got back, he finally let us do the upgrade. Not a problem since.

Another .02 with a story.

carl could not agree more even if it seems like a strange move.i would replace broken shaft,prop with 11/2'. not prudent to replace with 13/8" and expect any improvement.i guess you might say you are half way into "doing the right thing".

Carl,
What you say makes sense. My boat is in a cradle lift, the new shaft will be done tomorrow, I'll be out $650, I'll be fishing by Friday, that's the way I'm going for right now. I'm already using struts that have been punched out to accommodate the 1 3/8' shafts. Right now, I'm not ready to pull the boat and redo both struts, stuffing boxes, shaft alleys, and, the shafts. For short Money, I'll be ready to rock and roll asap. What I'm really needing, fellas, is some advice on some bad ass props for Reel Cowboy. If you guys can help, great. If not, thanks anyway.
John.

Any shop I've ever had work on, tweak or anything otherwise on a prop always kept a record of end size whether the props were reworked numerous times even if I did not keep a record. The 1.5:1 ratio you use is not a common power boat Yanmar ratio. All my info is for 2:1 ratios.

Other than a slight difference maybe for the ZF reverse rotation if your prop person allowed for that, pull the opposite prop and have them scan it for diameter, pitch and cup. Its gonna be damn close and then you can tweak from there.

JohnCranston wrote:Carl,
What you say makes sense. My boat is in a cradle lift, the new shaft will be done tomorrow, I'll be out $650, I'll be fishing by Friday, that's the way I'm going for right now. I'm already using struts that have been punched out to accommodate the 1 3/8' shafts. Right now, I'm not ready to pull the boat and redo both struts, stuffing boxes, shaft alleys, and, the shafts. For short Money, I'll be ready to rock and roll asap. What I'm really needing, fellas, is some advice on some bad ass props for Reel Cowboy. If you guys can help, great. If not, thanks anyway.
John.

Got it, have to fish when they are there.


$650 is a pretty dam good price....is it at least A-22? Or A-19.

At this point, maybe skip the Bad Ass props and use whats available as losing another prop is not out of the question. Not to mention Bad Ass props...they are bad ass cause they are hooking up, or have less slippage great for haulen ass...not so great with undersize shafts.

Again...just my .02

Thanks, Bruce,
Scott, off the board,gave me those props, and, I know where he got them reworked...I'll give them a call. As far as the 1.5 ratio. my bahia is 2,000 lbs lighter than most others out there...everything is Nida-core or Cabrera. I feel like the performance speaks for itself...I posted 35 knots but it's more like 36..up on plane in an instint and blows through any seas that we've encountered. I think that Richard Mastery gave me good advice.
Thanks again,
John.[quote][/quote]

Hi John,

I hope this helps. We are also running 1.5:1 gears 315hp Yanmars, 1 3/8 shafts, with Michigan nibral 18x20 djx 3 bladed props in a very light Bahia mar. We have 1450 hours and have had no shaft issues. This setup was recommended to us by Al Grovers Marine in Freeport, NY. The boat turns 3850 loaded at 36.4 knots in the spring when it first goes in the water. She slows down a little bit at the end of the season due to bottom growth. We are averaging 100 gallons of fuel on day trips to the canyon, running anywhere from 70 to 100 nm each way, with 8 hours of trolling. We like to run at 26 to 28 knts, anything more is getting a little squirrely.

Regards,
Chris Holgerson

Bruce,
Come to find out, the props were Michigan Dyna-jets with no alterations except number 3 cup...found a used pair after calling a bunch of shops...37 knots wide open and am very happy.
Carl,
The shafts were a19's...that's all he uses and had it done in a couple of days...thanks for your advice.
Chris,
you gave me good advice years ago on gear ratios and props, which I took, and am completely satisfied.
Bob,
You were a huge help....
Thanks again.
John.

i had the honor of your presents on my boat at a Bertram rendezvous years ago please come back for another round of drinks on me.

Bob,
Do you serve doubles?
You're a class act, Bob, and what I like so much about you is, you think outside of the box...I tried to emulate your expertise when deciding on engine placement and shaft angles when we put together Reel Cowboy, and, it really payed off nicely.
Thanks again, sir.
John.
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