Offset gearbox

[doinguptheboat]

Hi,

We are considering re-engining our Seamaster 27 which currently has a Ford Wortham Blake petrol with Hy-Drive gearbox. (we know it doesn't make financial sense!) The reduction box has a horizontal offset, so the engine is not in line with the prop shaft.
Does anybody know of any modern gearboxes the have a horizontal offset?
Moving the engine in-line with the shaft will mean removing the current, rather substantial, engine bearers and installing new ones. We don't want to re-use the Hy-Drive 400 box as spares are pretty well non existent and it has a couple of small oil leaks.
If we have to we'll remove the bearers, but it would be a lot of work.
A second question, do you think 27hp would be ok for pootling about on the Nofolk Broads or Great Ouse?

Many thanks
Simon

 

[Ferris]

We used to have a Seamaster 30 with an offset G/B, a TMP brand. Our model is probably completely obsolete but it looks like TMP still exist and provide an offset G/B: http://www.thameswaymarineproducts.co.uk/transtyp.htm

May still be cheaper to build new bearers anyway, also they may need rework to accommodate the new engine. The seamaster 30 had a perkins 4107 and did about 5-6kts. 35hp would be fine in a narrower, shallower hull like the 27 so long as you won't be plugging against river flow.

 

[doinguptheboat]

Thanks for the reply. I'd forgotten about the TMP boxes, a tad on the expensive side though. I think you could be right about the bearers needing work anyway, most of the modern diesels seem to have a much narrower footprint. I know Beta Marine will manufacture feet to match existing bearers, for a price, but probably cheaper to redo the bearers!

Cheers
Simon

 

[Tranona]

If the current bearers are sound then you may be able to fabricate a steel framework that picks up on those and mounts your new engine in line with the shaft. As you say modern engines have narrower footprints so it may well still be within the space between the bearers.

 

[burgundyben]

Isn't your gearbox a drop centre one that has been indexed round?

 

[ian2008]

Beta marine will turn their gearbox on its side and provide offset engine mounts.
I have seen one in a freeman 23 which has a similar offset( 4.5") from memory.
The engine and gear box fitted inside the original engine box under the seat and the shaft lined up perfectly.

 

[doinguptheboat]

If the current bearers are sound then you may be able to fabricate a steel framework that picks up on those and mounts your new engine in line with the shaft. As you say modern engines have narrower footprints so it may well still be within the space between the bearers.

Had a look and unfortunately I don't think this is an option.

Simon

 

[doinguptheboat]

Beta marine will turn their gearbox on its side and provide offset engine mounts.
I have seen one in a freeman 23 which has a similar offset( 4.5") from memory.
The engine and gear box fitted inside the original engine box under the seat and the shaft lined up perfectly.

Interesting, may have to look into that. How does that work re filling and checking the oil level?
Our previous boat was a Freeman 22 - loved that boat...

Simon

 

[doinguptheboat]

Isn't your gearbox a drop centre one that has been indexed round?

I don't think so. The offset reduction box hangs off the back of the gearbox and I think could only fit one way.

Simon

 

[ian2008]

Beta re engineer the filler and vent on the gearbox.
They move the dipstick as well, comes with full warranty still

 

[doinguptheboat]

Beta re engineer the filler and vent on the gearbox.
They move the dipstick as well, comes with full warranty still

Thanks for that, very interesting to know. Sounds like some enquiries are in order in the not too distant future! I've always heard good things about Beta Marine engines - just hope I don't pass out when I hear the price...

Thanks to everyone again
Simon