English: Sabb 2G with 2GRG gearbox

[robertbastiaan]

Hi all,

 

I am new here so my first question. I am strugling with the fact how to install my Sabb Diesel in my lifeboat. The old construction was with a fixed coupling between the original SABB gearbox directly through the hull. The bearing in the hull is broken so I need a new one for that. My idea at this moment is to mount the Diesel directly on the foundation without rubbers. This was also the way it was installed in the lifeboat. Then use the old original Sabb coupling and a new water lubricated bearing. This bearing is mounted on a shaft that is laminiated in the hull. This way I can do easy aligning of the engine with the shaft.

 

the problem is that no body is able to give me a suitable reaction on this. The "problem" is that the shaft of the gearbox has a lineair movement and I do not know if a water lubricated bearing is going to leak with this setup. Is there anyone that has experience with a system/setup like this? Maybe someone has a similar setup and has some pictures of the system.

 

The engine I have is a SABB 2G with a 2GRG gearbox. Estimated year if origin si 1976. https://baatplassen.no/bildearkiv/25/25764/sloep_004.jpg

 

 

Hope to hear from you.

 

RObert

[Fiks]

Hello Robert,

 

I have a 25 ft. wooden motorboat with a Sabb 2H with CP propeller. I am now working with the shafting arrangement,

replacing a corroded stentube and damaged frames due to "nail sickness"

 

The linear movement of the shaft mentioned by you, have you seen that on your gearbox or do you mix this information with the CP propeller system that is actually working by moving the propeller shaft in the axial direction?

 

The sketch below is taken from the Sabb 2G manual and shows the shafting with water lubricated bearing.

 

 

If you don't have that manual, it is possible to download manuals and spare part list here: Sabb instruction manuals

 

Best regards

Fiks

[robertbastiaan]

Hi Fiks,

 

 

thanks for your reaction! The original Sabb gearbox was mounted on a solid propeller with shaft, so no variable pitch propeller. The linear movement comes from the gearbox number 4 in your drawing. As it is a minor movement it can cause a lot of problems when the currect water lubricated systems are not up for the job Sabb requires. Nice to see that you have found a manual with this drawing, but i have sat down for an hour and starting to feel a bit... stupid. But sorry, I can not find it. I have opened all manuals in all languages, but starting to get the feeling I overlooked it. Can you be more specific or add the specific link to the document if it is not to much of work? The 2G manual i found does not have the part you mention in your post.

 

For now my gut feeling tells me that the water lubricated propellor shaft is the solution.

 

regards,

 

robert

[Fiks]

Hello Robert,

 

The sketch I posted was taken from the installation part of the Norwegian manual for the engine. Unfortunately the pages concerning the installation are not included in the English manual. I assume that you can use any water lubricated propeller system that suits a 32 mm propeller shaft for your engine. I have also looked at the drawing of the gearbox in the spare parts catalogue, it appears that the propeller shaft has a longitudinal movement of a few millimetres between forward and aft position as told by you. I don't assume that this movement will cause any problem for the aft rubber bearing and the stuffing box because this configuration is also used for CP propeller plants with tension tube, which also has a longitudinal movement thru the sterntube.

 

 

Best regards

Fiks

[robertbastiaan]

Hi Fiks,

 

thanks for your efforts. I think i will order the system today. Time is running out and the weather is starting to get better. Your information is verry helpfull!

 

regards,

robert