Perkins 4108 and Hurth gearbox

[pappaecho]

When I bought the boat in November, the surveyors report highlighted that the prop was too close to the hull - only about 1.2 cms.

The solution is to move the propshaft back by about 35mm. There is no adjustment on an E32, so the usual route is to make a spacer between the gearbox and the shaft flanges.

I need either a drawing or a measurement of the the flange on the Hurth gearbox... can anybody help please?

 

[AndrewB]

There are some dimensions shown here.

It isn't usual to attach the gearbox direct to the shaft flanges. Normally one of these couplings is fitted in between, which perhaps would solve your problem? It is a very standard part for Hurth gearboxes, and any decent marine engineer (like Lancing Marine) would stock it.

 

[minquiers]

look in the asap web site , they have a shaft extension, they call it a bobbin,its in the same section as shaft couplins, fitted one on my boat and works perfectly, could be your cheap answer.

 

[jerryat]

Hi Andrew,

Sorry, don't agree with your statement ....

> It isn't usual to attach the gearbox direct to the shaft flanges <

It certainly isn't UNUSUAL in my experience. I've owned four boats where this is precisely what happened and many, many other boats have couplings made that way. A lot depends on the factors involved, length of shaft, intermediate supports, fixed or flexible engine mountings etc etc, where a flexible coupling may be desirable, but not every time!

Cheers Jerry

 

[AndrewB]

Apologies, I stand corrected. I can recall seeing about six 4108/Hurth installations (including my own) and thought from memory all had some form of shaft coupling.

 

[pappaecho]

This one definitely has not... but as the prop is so close to the hull, it suggests that the previous owner removed it when the cutlass bearing was replaced.

Obvious solution then to fit one and return the prop to its rightful position ... this will keep me out of the pub for a couple of days next week!