[C320-list] Ahoy owners with Perkins engines

[Warren Updike]

>From what I understand, a flex coupling has two main benefits: 1) provides a
level of vibration isolation; 2) acts as a shock absorber in the even of a
fouled or struck prop.

Typical engine room soundproofing will reduce the noise that is transmitted
through the air. However, a fair percent of engine noise is not transmitted
through the air; but, directly through the hull as vibration via the
transmission, engine mounts, and shaft. A flex coupling dampens some of this
vibration preventing it from reaching the hull. The primary function is to
protect the drive train.

Not much chance of striking a prop on the ground with a sailboat; but, here
in the Chesapeake it's not at all rare to capture a crab trap line in the
prop. I've had several such incidents, and a very common event is for the
line to wrap on the prop/shaft and haul in the float to wedge between the
hull and prop. Nothing will stop your engine as fast. Imagine the stress on
the drive train. With a flex coupling, the shock is absorbed by the
coupling. The coupling might even part. Better to ruin a $300 coupling than
have a bent prop, shaft, and/or other damage.

Warren & Pattie Updike
Catalina 320, #62, "Warr De Mar"
Middle River, Chesapeake Bay


-----Original Message-----
From: Kirk McCullough [mailto:kirk.mccullough at telus.net] 
Sent: Monday, October 26, 2009 11:24 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Ahoy owners with Perkins engines

It's a good thing to keep in mind. I did the SS shaft at the same time and
also installed the Kiwi prop. The Kiwi puts a heck of a load on the gearbox
in reverse so I feel safe with ZF10.

Whats the benefit of the flex coupling?

Kirk

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Warren Updike
Sent: 24 October 2009 13:26
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Ahoy owners with Perkins engines

Yes, in fact when I contacted Foley about rebuilding my Hurth 50, they
recommended I go to the ZF10/Hurth100. I think it is about 10mm longer than
the ZF5/H50; and, indicates that I should shorten the shaft which I decided
not to do. Instead, I had the HWB50 rebuilt at a shop near Annapolis for
about $750.

In the future should I find the need to deal with the transmission again, I
will definitely go with the upgrade, replace the shaft with SS, and add a
flex coupling. I figure that will cost about $700.

Warren & Pattie Updike
Catalina 320, #62, "Warr De Mar"
Middle River, Chesapeake Bay

-----Original Message-----
From: Kirk McCullough [mailto:kirk.mccullough at telus.net] 
Sent: Friday, October 23, 2009 3:55 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Ahoy owners with Perkins engines

Another option is to get the ZF 10 (hurth 100) which is designed to take the
29 hp the Perkins can deliver, in fact as I recall it's good up to 45 hp.
The ZF 5 or ZF 6, just like the Hurth 50 is really on the edge of the
specification for our engines. The ZF 10 a little longer but otherwise is a
direct replacement.

Kirk
#124

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Warren Updike
Sent: 22 October 2009 09:27
To: c320-list at lists.catalina320.com
Subject: [C320-list] Ahoy owners with Perkins engines

Actually, this is about your Hurth transmission. FoleyEngines.com is an
authorized facility for Perkins and ZF/Hurth products.  This is not a
recommendation, just a heads up for owners that may not know about Foley.
Check this out:

http://archives.subscribermail.com/msg/9ca93553bbd5413abfd0e5ce4695fe78.htm

 

Warren & Pattie Updike

Catalina 320, #62, "Warr De Mar"

Middle River, Chesapeake Bay