Tartan 37 or Westerbeke 50 Owners, I have a question

[JeremyLembo]

Good day all;

I have a question for you all. I have a 33' Morgan Out island that was repowered by it's previous owner with a Westerbeke 50. My boat is severely Under propped and my questions to Michigan Wheel are rather ill received. So, I need a new prop and I would like to know What you have on your boat, and if you are happy with the performance. My specs are similar to the Tartan 37. Diameter and Pitch would be great information to have since what I have does not work well.

[Geitz]

What's the top speed can you make under power?
Can the engine reach max rpm in forward gear? ~3200rpm
Is your prop clean?
Is the bottom clean?

[JeremyLembo]

Bottom and prop clean, I can push about 6knts if there is no wind. if there is wind, I will go backwards. I have no cap on RPM's. engine does not even see the prop at all. In gear, I can thrust like my van in Neutral. :-)

When I put the engine in reverse it takes a few seconds for the boat to react.

[Geitz]

Did you try using Michigan Wheel's prop calculator?
For speed, I think you enter the hull speed for your boat, maybe ~ 7kts?
Do you know the gear ratio?

Do you know the pitch/diameter of the prop that's on now?

[JeremyLembo]

Oh yea. I even called them. They don't like me anymore. :-)

They basically told me I am screwed in a way. Math does not work, etc...
They pretty much told me to Repower. I told them a new prop is cheaper than a new engine. If figure, if a Tartan 37 with same engine/tranny combo works for them, it's better than what I have now. 2:1 gear box. The Westerbeke 50 was a rather specific engine built for not that many things. When i was rebuilding most of my engine, I spent a lot of time on the phone with Westerbeke.

[jibstay]

Are there any prop size limitations, such as distance between shaft and hull or rudder?

If not, email Flexofold and give them your engine and transmission specs and they will provide a recommendation.

[Geitz]

I had quite a different experience with Michigan Wheel. They recommended I have my prop re-pitched instead of replacing, as my boat was over-propped.

So,you might talk to Scott at Proper Pitch. scott@properpitch.com
He was very helpful.

[JeremyLembo]

Those are some good options.

I don't have any space limitations. There is Plenty of room down there.
Repitching is a little expensive. Here in Florida, we have a lot of props floating around for not a lot of $$. Even Ebay, there is a 17x22 for like 75 bucks. :-)

[Geitz]

The re-pitch cost me $112, including shipping.

Is your current prop a 3 blade?

[Cheechako]

Is your Westerbeke 50 a Perkins 4-108? If so you have plenty of power, you just need to find the right prop. Put the biggest diameter that will go on and still leave 15% of diameter clearance to the hull.

[JeremyLembo]

Current prop is a 3 blade bronze. I still don't know what to pitch it up to. Just redid the Michigan wheel calculator and it says I need a 22" prop. LOL... just a tad larger than the 17" one on there.

The boat used to have a perkins on there. The previous guy repowered with a 1964 diesel. most likely due to his lack of funds. Engine purrs! even for being that old.

[JeremyLembo]

LOL... it seems that not one person with a Westerbeke 50 knows what prop they have on their boat. sigh. I am just going to have to look at boats for sale and then look at their props. LOL

[TrentePieds]

A 15Dx10P will be about right.

Have a go at this calculator, but remember that "garbage in -> garbage out". Check your design parameters so you are close to the truth before you enter them in the calculator.

There is only one way to know what's on there now. It'll be stamped on the hub.

Vicprop - Propeller Calculator

TrentePieds

[Kentb]

Our Tartan 37 is currently configured with a W-40 which is about 9 less HP at 3000 rpm.
We have a 2 blade feathering 17" set at 9.1" pitch. We make 6.6 knots at 2400 rpm.
From the T-37 forum, it seems that a 3 blade 17"x6" is what they use with W-50's

Just a few numbers for ya...

Btw Perkins 4-107 is the base block for a w-40 but NOT the w-50 (which is 110 ci) recent discussion reveals it may be an MG/British Leyland block @ 1.8 liters.

[Stu Jackson]

Originally Posted by JeremyLembo

LOL... it seems that not one person with a Westerbeke 50 knows what prop they have on their boat. sigh. ...

No, Jeremy, all this means is that of the thousands of folks who have W50s on their boats, they are not reading your particular post. It's nothing personal.

One "traditional" question not yet raised is what transmission you have and what the reduction gear is. IIRC, it's an important part of the equation.

Good luck.