Forum Replies Created
- Replies
I have a copy of C24586 and it gives the dimension of the middle chock as 6’2” from the aft one (centre line of chock to centreline) and 11’6” from the forward one.
Hope that helps – it’s always nice to have the exact measurements.
If you want a copy of the plan I could sort one out for you?
Regards,
Simon
Trevor,
Personally, I would be really cautious about using stainless under water or any where without contact with oxygen (ie buried in wood) especially if galvanic action comes into play – as I am sure you are aware Stainless & aluminium are poles apart galvanic wise. I have had personal experience (on a previous boat) to this effect – stainless looks ok on the outside but in the wrong circumstances crystallises & weakens internally. This is the main reason why I went for aluminium again on my pintle (though as with stainless you need to consider the grade you need for the job in hand). It’s also why I have taken steps to isolate the stainless from aluminium – at least a visual inspection of aluminium or steel etc tells you when its time to get a new one.
Regards,
Simon
Trevor,
I did think about sending the details. They have done a good job but it has taken a long time – they seem busy and it was a small job and certain machines were set up and in constant use. To balance and in fairness sorting the exact grade of aluminium & supplier was the biggest issue time wise.
If you do use them I would recommend sending them the old rudder & drawings.
http://congleton-engineering.co.uk/
I dealt with Rory but I think he will still be on holiday next week – 01260 279647.
All the best with it & keep us updated.
Regards,
Simon
Murray,
You are so right!
The guy who ended up finishing the job is a real craftsman the main pin & though holding pin fit perfectly. When the measurements from the plan are cross checked they are all spot on. The main pin was put in upside down (I didn’t leave the old fitting as I wanted to scarf in some new wood – probably a mistake (in the end) not to) but because he had put the retaining pin in dead centre (main pin has a shoulder) it wasn’t a problem.
Forget fine art, sculptures & the like I could look at this for a long time – almost a shame it’s not going to be seen.
Regards,
Simon
I finally got my new pintle back today. Milled from a chunk of 7075-T6511 aluminium (rather than the original welded version in 3/8″ plate – I think that later boats were milled from solid bar?) with 316 stainless pins by Congleton Engineering (I think that they have done a Stella job – though it did cost £215). I have isolated the stainless pins from the aluminium with Duralac. I would have liked to have got it anodised but balked at the £132 min charge I was quoted (from another company) and I was also concerned about getting it back quickly! The old one did 50 years – so it will see me out & some!
Murray, Tim
Many thanks for both your responses – it’s really appreciated. Now that I have seen Murray’s photos and have managed to get my spare apart (though it’s not in as good a condition as I had hoped) I am less concerned about the one on Gambol failing.
I still can’t get the one off Gambol despite lots of heat, freeing spray, oil and blows with a lump hammer.
I will have another go at the end of the season (I think I will end up cutting it off) and put up with the excessive play – I have wasted enough time on it for now!
Many thanks again,
Simon
Dominic,
Many thanks – heat and rotation has sorted out the replacement. The one on Gambol is still putting up a fight – I will have another go in the next few days.
Many thanks again,
Simon
Murray,
Many thanks for having a look – it’s really appreciated. I have since found a spare, in a box of bits I didn’t know I had! Unfortunately as you might expect it’s only in a little better shape than the one I removed.
I have the drawing for it now so I will go and see what the engineering firm makes of it sometime in the next few weeks.
Regards,
Simon
Many thanks for the replies.
I have already come to the conclusion that I will look into getting a new one made in Aluminium – Trevor my cheque for the drawing is already on it’s way.
The only problem still is which grade to use. If I have this right the original made from Hiduminium? had an ultimate tensile strength of 61k to 72.5k psi. 5086 or 6061 marine grades are around 45k psi. How much of the original specification was down to the material being available and was it over engineered? I really don’t want to find out the hard way.
7075 (used in aircraft industry) has the strength but, from what I can find out, is not so happy in a marine environment. Though as Trevor says, the key is to prevent salt water reaching the aluminium in the first place and the original has managed 50 years with inferior sealants to those available now.
I will go and see what the engineering firm, I used to have the prop shaft reworked, in the New Year have to say – though Crewe engineering firms are more used to working with bits for trains than boats.
Simon
