Tiller

[Mondo99]

New narrowboat owner. 
I have a 55ft narrowboat, I bought this 3 years ago, it was built in 2003 but has never been in the water, I am now nearing completion, the boat did not come with a tiller so I need to fit one. What it does have is a rudder and a 40mm bearing/bush assembly that bolts onto the stern of the boat. The rudder has had a 40mm ID square tube welded into the top of the rudder, is approximately 100mm deep and protrudes above the rudder about 10mm. As an engineer I prefer to do all the work on the boat myself, I do however have some questions:

Do I need to use solid bar or will thick wall tube be up to the job, I can get some 40mm x 3.25 tubing.

I have seen on other narrowboats there is normally a joint just above the bearing, is there any reason why I cannot have a one piece tiller.

My thoughts at the moment are to make the tiller out of the thick wall tube. Where it enters the square tube on the rudder I could sleeve it internally with solid bar, about 200mm and then bolt the solid bar with 2 x 12mm SS bolts to the square tube to allow me to fit and remove the tiller. Will this set up be strong enough? 

Do I need to use solid bar where it enters the rudder, would thick wall tube on its own be strong enough, would sleeve inside the tube. 

Is it normal practice to fit a secondary bush close to where the tiller enters the rudder?

With this set up there is nothing to stop the rudder lifting up out of its lower pivot point, I can make something to stop this but what method is normally used. 
Question 2

The engine I fitted to this boat was a very good Yanmar 3YM30 (30hp) marine engine that I already had, I am now not sure wether this will be powerful enough.

Any advise on the above greatly appreciated. 
 

 

 

[Jen-in-Wellies]

Welcome to the forum. Do you have any photos of the tiller/rudder area? We like photos.

[Mondo99]

Could get some at the weekend. 

[magnetman]

The reason for having it in two parts is to be able to remove the tiller (Z iron, ramshead, swan neck there are different names) so that the bearing can be replaced or rudder removed for other reasons. 

 

You could just weld it on and be prepared to cut the weld later if rudder needs removing. 

It has probably been done but due to the turning forces it would want to be serious welding. 

 

Solid bar is preferable but thick wall tube is better. 1/8 inch (3.125) is not very thick. 

 

I have seen a tiller made with plasma cut plate and a flange welded on each side but it looked a bit wrong and seemed quite a lot of work. 

 

 

 

 

 

I think it is worth closely copying the original style to reduce vibrations. 

[Tracy D'arth]

Hollow section will not last long, use solid. 

The joint is to enable removal for repair to rudder and top bearing which will wear and rust.

Bolts through joints have a habit of loosening, wearing and shearing. Liverpool fixed all their rudders with through bolts, they are a frequent cause of looseness and rattles.  There have been all sorts of "remedies" that don't work. Most end up being welded on solid which then makes subsequent repair complicated.

The pro way of joining the short shaft on the rudder and the tiller shaft is a square taper about 4" long on solid bar. With the male taper on the tiller shaft so that it can be tapped free and pulled up through the bearing. The joint is just above the rudder blade. No bolts, just a tight fit. So no looseness or rattles.

The rudder should be able to come out of the bottom cup, the first time you carelessly sit it on a lock sill when descending you will be glad that it can.

[David Mack]

2 minutes ago, Tracy D'arth said:

The pro way of joining the short shaft on the rudder and the tiller shaft is a square taper about 4" long on solid bar. With the male taper on the tiller shaft so that it can be tapped free and pulled up through the bearing. The joint is just above the rudder blade. No bolts, just a tight fit. So no looseness or rattles.

There's usually a bolt (or stud and nut) to keep the swan neck tight on the taper on the rudder shaft.

1 hour ago, Mondo99 said:

The engine I fitted to this boat was a very good Yanmar 3YM30 (30hp) marine engine that I already had, I am now not sure wether this will be powerful enough.

Depends on how well matched the gearbox and prop are to the engine. But in principle 30hp will be fine on a 55 ft boat. Loaded 70 ft working boats towing a loaded butty managed on less.

[Tracy D'arth]

1 hour ago, Mondo99 said:

Question 2

The engine I fitted to this boat was a very good Yanmar 3YM30 (30hp) marine engine that I already had, I am now not sure wether this will be powerful enough.

Any advise on the above greatly appreciated. 
 

 

 

30HP is enough for a 70' leisure boat.  Most vintage engines only produced 30HP but with a lot of low down torque.

The once most popular old engine was the 1.5D BMC which on a good day produced  around,    guess what?   30HP!

[Ex Brummie]

My Perkins 4108M is governed to 29bhp and has never come up short on a57ft boat. It is coupled to a PRM150 2:1 ratio.

[blackrose]

7 hours ago, Tracy D'arth said:

Hollow section will not last long, use solid. 

 

 

It depends on wall thickness but if it was thick enough, say 6mm then there might not actually be that much difference. The vast majority of torsional strength of a shaft comes from the material around its circumference.

7 hours ago, Tracy D'arth said:

 Liverpool fixed all their rudders with through bolts, they are a frequent cause of looseness and rattles.  There have been all sorts of "remedies" that don't work. Most end up being welded on solid which then makes subsequent repair complicated.

 

 

While I agree with this assessment I've never actually had any problems with my 2005 Liverpool boat rudder fixings. I replaced my rudder recently but only because someone had made a nice fishtail profile rudder for me. I also replaced the bolts. 

 

I know that the LB method of doing it was far from ideal, however I also think that there are far more LBs out there like mine that have never had a problem with a sloppy rudder than those who have, and the majority of those who have had this issue would be the people who didn't bother to check the tightness of those bolts when their boats were out the water.

[Mondo99]

14 hours ago, Tracy D'arth said:

Hollow section will not last long, use solid. 

The joint is to enable removal for repair to rudder and top bearing which will wear and rust.

Bolts through joints have a habit of loosening, wearing and shearing. Liverpool fixed all their rudders with through bolts, they are a frequent cause of looseness and rattles.  There have been all sorts of "remedies" that don't work. Most end up being welded on solid which then makes subsequent repair complicated.

The pro way of joining the short shaft on the rudder and the tiller shaft is a square taper about 4" long on solid bar. With the male taper on the tiller shaft so that it can be tapped free and pulled up through the bearing. The joint is just above the rudder blade. No bolts, just a tight fit. So no looseness or rattles.

The rudder should be able to come out of the bottom cup, the first time you carelessly sit it on a lock sill when descending you will be glad that it can.

• Some excellent advice there Tracy, lots to consider. 

[Tracy D'arth]

I got my top and bottoms confused there.  I will try again.

The female taper is in the solid rams head that the z swan neck tiller bar is welded to and the male taper is on the rudder shaft stock so that the joint is above the deck. There is a big thread on the top of the male taper and an equally big nut on the top of the rams head to hold the taper tight.

 

Edited October 25, 2023 by Tracy D'arth