Propeller shaft

[Brian1964]

Hi Folks, I am new to boating so apologies for my lack of knowledge.

I purchased a project canal boat 8 months ago (not a narrowboat) that was to be electric propulsion.

As I have not been able to find someone to assist me with this or use the inboard kubota beta engine (This was to be used as the generator to charge the batteries) to drive her, I have decided to put an out board on and pursue the electric option at a later date.

My problem is the shaft coming out the stuffing box. Do I just need a female 40mm  stuffing nut here to make this water tight and leave the propeller shaft in place with propeller for the future. Or is it best to remove and blank this off.

Another issue I have is I have a castle nut that keeps the propeller on but there is no hole in the shaft to put the slit pin in (I am not keen to drill the shaft as I will probably damage the thread) Is there an alternative or is this ok without the split pin.

 

Thank you so much for looking and any replies that I may receive.

 

Brian

[john.k]

A nylock nut is often used on speedier boats with satisfaction............just be sure the thread comes right thru the nylock insert by  1/4" or so......If its a stainless shaft,be a bit careful of nut material.....as stainless will jam on stainless,and you will have to split the nut to get it off..........never damage the shaft thread ,it will be costly to replace.

[Tony Brooks]

I don't think John.k understands the question.

 

You do not have a stuffing box on the outside of the boat as shown in your photos. The stuffing box goes on the inside of the boat at the front of the stern tube.

 

You can see the stern tube with a thread on it and you can also see a fluted shaft bearing inside the tube and supporting the shaft. It so probably a Cutless rubber bearing and when you come to use the shaft you will need to sort out a thorough water supply for it. The instructions for the Vetus stern gland will give you some ideas.

 

If the shaft is redundant for now, and you have a working stuffing box on the other end of the end of the stern tube, the inside, then it should not leak any water if you leave it as it is, but what would normally fit there with all sorts of variations in shaft bearing location, method so securing etc. is a bronze casting that  screws onto the end of the tube with a flange to bolt it to the boat. I will see if I can find an image, but you wlil probably need to know the thread size etc. on the end of the shaft.

 

 

It is the thing on the left. If you keep that fluted bearing then the rectangular holes to let water are important.

 

It seems T Norris marine may have the part you want, bottom two rows, probably the last row seeing where your shaft bearing is located.

Edited July 22, 2022 by Tony Brooks

[Brian1964]

 

30 minutes ago, Tony Brooks said:

I don't think John.k understands the question.

 

You do not have a stuffing box on the outside of the boat as shown in your photos. The stuffing box goes on the inside of the boat at the front of the stern tube.

 

You can see the stern tube with a thread on it and you can also see a fluted shaft bearing inside the tube and supporting the shaft. It so probably a Cutless rubber bearing and when you come to use the shaft you will need to sort out a thorough water supply for it. The instructions for the Vetus stern gland will give you some ideas.

 

If the shaft is redundant for now, and you have a working stuffing box on the other end of the end of the stern tube, the inside, then it should not leak any water if you leave it as it is, but what would normally fit there with all sorts of variations in shaft bearing location, method so securing etc. is a bronze casting that  screws onto the end of the tube with a flange to bolt it to the boat. I will see if I can find an image, but you wlil probably need to know the thread size etc. on the end of the shaft.

 

 

It is the thing on the left. If you keep that fluted bearing then the rectangular holes to let water are important.

Thank you Tony for your reply. I assume it is only the thing on the first third of the picture and the flattish plate bolts onto the boat. The thread is approx. 40mm (will measure more accurately). Do you have any idea what it is called?, Sorry for being a bit clueless.,

Thanks again Brian

[BEngo]

You need an "outboard housing for a Cutless bearing".  Item 0020 in Tony's first set of pictures.  You will need to specify the thread correctly, both diameter, pitch and type (55 or 60 degrees)  As you say, the outboard housing  bolts to the boat and the bearing screws into it. 

 

N

[Tony Brooks]

13 minutes ago, Brian1964 said:

 

Thank you Tony for your reply. I assume it is only the thing on the first third of the picture and the flattish plate bolts onto the boat. The thread is approx. 40mm (will measure more accurately). Do you have any idea what it is called?, Sorry for being a bit clueless.,

Thanks again Brian

 

I think that you have yet to grasp that apart from modern production cruisers and yachts boats are very much one-offs. Your hull shape makes me think GRP, moulded ply or possibly sheathed carvel built wood. If so that metal plate is probably an addition that has been fitted for some reason. I don't think it has  much to do with the shaft and stern gear apart from the fact that when the rear housing/casting is fitted it will have to be drilled and tapped for the screws that prevent it rotating. The thread on the stern tube will hold it tight against that metal plate or the back of the keel.

 

I do not understand your first sentence. I think the plate that looks as if it is bolted to the back of the keel and extending along the skeg may be hiding hull damage/rot. The other thing could be to reinforce a wooden skeg because over the years the prop wash erodes them so they break.

 

I am sorry but I am not prepared to do all your research for you. Visit this site https://shop.tnorrismarine.co.uk/pages/custom-stern-gear

and study it. Phone Norris if you need to. Note the tables with all the dimensions on it. You will need the thread size and form that is on the tube and the length of the PARALLEL section of the shaft where it comes out of the back of the boat.

 

6 minutes ago, BEngo said:

You need an "outboard housing for a Cutless bearing".  Item 0020 in Tony's first set of pictures.  You will need to specify the thread correctly, both diameter, pitch and type (55 or 60 degrees)  As you say, the outboard housing  bolts to the boat and the bearing screws into it. 

 

N

 

Not sure that he needs a Cutless bearing housing because he has the bearing in the back of the tube, a plain one will probably do, but I can't see any problem apart from possibly cost if he fits a Cutless bearing one.

[Alan de Enfield]

Maybe I'm being too simplistic, but if you are going to use an outboard you can dispense with the original shaft drive completely - remove the shaft (store it for if you ever decide to put an inboard in) and have the hole plated  (weld a disc over it).

 

You can then fabricate your transom mounts for the outboard.

[Tony Brooks]

56 minutes ago, Alan de Enfield said:

Maybe I'm being too simplistic, but if you are going to use an outboard you can dispense with the original shaft drive completely - remove the shaft (store it for if you ever decide to put an inboard in) and have the hole plated  (weld a disc over it).

 

You can then fabricate your transom mounts for the outboard.

 

I don't think he even needs to do that because the inboard gland should stop any leaking. I bet the transom is so far back the outboard would not foul the shaft.

[Alan de Enfield]

4 hours ago, Brian1964 said:

I have decided to put an out board on and pursue the electric option at a later date.

 

 

Are you aware of the additional safety requirements required to get the BSS (Safety Certificate) when having petrol on board ?

 

 

[Brian1964]

Thank you all for your replies. Thanks tony for the info on the flanges. I would prefer not to weld a plate over as I may explore going electric in the future, I am aware I will need a certificate for the petrol but would have needed one anyway for the diesel generator. Thanks again all. Brian

[Alan de Enfield]

8 minutes ago, Brian1964 said:

I am aware I will need a certificate for the petrol but would have needed one anyway for the diesel generator.

 

The Boat Safety Certificates is for the whole boat, but the requirements are more onerous is you have petrol aboard - example - you can only have a certain make / model of gas fridge, if you have a diesel engine then you can have whatever fridge you want.

[Brian1964]

4 minutes ago, Alan de Enfield said:

 

The Boat Safety Certificates is for the whole boat, but the requirements are more onerous is you have petrol aboard - example - you can only have a certain make / model of gas fridge, if you have a diesel engine then you can have whatever fridge you want.

Thanks for the info Alan ,I was not aware of the difference.

[john.k]

I do realize the situation,however the OP does have a new looking stainless propshaft,and was asking about drilling a hole in it for a splitpin.........This was the point I adressed.

Its quite likely you can hold two discs with a piece of allthread thru the shaft log to exclude water.......no need for costly bronze fittings ,if they being used.

[Brian1964]

Thanks John, I have a bronze castle nut to hold the propeller on but there is no hole in the prop shaft for a slit pin. I was a wee bit concerned that this may then work its way loose.

 

Thanks again

Brian

[Tony Brooks]

If you are going to refit the prop, and I am not sure about the wisdom of that, by all means use a nylock nut but if doing so and as long as sufficient thread extends from the nut I would always drill the shaft behind the nut and fit a split pit so if the nut did work loose it could not come off. This is more important as you do not seem to have a weed hatch, canal boat style, that allows you to more easily check the security of the prop and nut.

 

Unless you can lock the shaft the prop may freewheel when the OB is used and that tends to create more drag, so causing the OB to use more fuel. personally I would leave the prop off until you do away with the OB. You may find that you can lock the shaft by overtightening the stern gland/stuffing box.

[Brian1964]

38 minutes ago, Tony Brooks said:

If you are going to refit the prop, and I am not sure about the wisdom of that, by all means use a nylock nut but if doing so and as long as sufficient thread extends from the nut I would always drill the shaft behind the nut and fit a split pit so if the nut did work loose it could not come off. This is more important as you do not seem to have a weed hatch, canal boat style, that allows you to more easily check the security of the prop and nut.

 

Unless you can lock the shaft the prop may freewheel when the OB is used and that tends to create more drag, so causing the OB to use more fuel. personally I would leave the prop off until you do away with the OB. You may find that you can lock the shaft by overtightening the stern gland/stuffing box.

Thanks Tony. Much appreciated

 

[malp]

A comment about drilling the shaft, if/when you do it.  You will need drill bits suitable for drilling stainless steel, which you'll likely need to get from a proper engineer's merchant, not a DIY store.  Normal high speed steel bits are too soft and have the wrong cutting angle.   Remember that stainless steel work hardens, so  a suitable drilling technique is also required - if you're not sure then ask.

Edited July 23, 2022 by malp
typo

[Tony Brooks]

Toolstation sell cobalt drills that seem fine on stainless steel.