Mast-step ball centre [Robert]

[Archive]

Robert wrote:

Does anyone know if I can purchase a new centre for the mast step ball on my fifteen? It seems to have jumped out whilst I was towing home from the Nationals. I think that the Laser part no. is D00425.

Thanks to everyone who helped to run the Netley event - it was extremely enjoyable.

Cheers

Robert #1351

[Archive]

Bob replied:

Hi Robert,
I suspect that you have to buy the whole ball but speak to Brian Phipps at Windsport. I had it happen to me but as I worked in Engineering I had an apprentice make me up a new one. It has to be a pressed fit & it needs to be domed on top. A half decent approximation is to go to the builders merchants and buy a coach bolt with a domed head that looks about the right size. Buy a few so that you can practice and also have a spare. You then cut off the head with about 15mm of the shank (shaft) left on the head. There is a square section close to the head. Grease it (as it is mild steel and will rust) and fit it in the ball. If it is a loose fit remove it when trailing to stop it falling out. If it is a tight fit then you are lucky so you can hammer it in using a soft drift. It will not come out when the mast is in place as it is trapped. I see no reason why this should not work as a long term cheap solution provided that you keep it greased and keep a spare in case it rusts or falls out when the mast is not on the boat.
Regards
Bob

[Archive]

Robert replied:

Thanks Bob.

I shall have to drive more slowly on the B Roads in future. It was still there at the Warwick Services on the M40 but had mysteriously vanished by the time I had got out to the sticks. I'll try Windsport first as I suspect it is made from some clever material that is just the right hardness and doesn't rust. I'm also wondering if Laser would sell me a Dart 18 one which I could alter to fit. There mig htalso be a coachbolt in my garage that would do.

Cheers

Robert

(I'll catch you up one day and hope not to roll over straight afterwards!)

[Archive]

George Stephen replied:

Hi Robert,

The insert is made of stainless steel, and is supposed to be an "interference fit" - per Laser Centre who couldn't supply me with one - even though the Dart18 insert is the same as that for the D15. Laser Centre advised much as Bob did - but I'd go for a stainless steel bolt - measure the diameter of the hole you're trying to fill and go to a specialist "Fittings" shop to see what they can do. Expect to have to buy one that is too long, and cut it short. Go for one without a slotted head, and grind the head down to match someone else's insert - do most of the grinding first, leaving only a fine "tuning" so that the holes in the mast foot line up with the one in the ball.

I'd glue it in with a 2 part waterproof adhesive.

George

[Archive]

Robert replied:

Thanks George,

That's interesting - what is an "interference fit"?

Presently I am waiting for Windsport to let me know if they have one in stock, but I'm not holding my breath. I understand that the part number might be SM771 (Windsport catalogue).

Hopefully I shall be sorted for Carsington on 16th Sept.

Co-incidentally, Alex from Windsport has just telephoned to say that they haven't got one in stock but he'll try and get back to me tomorrow to let me know if/when they can source one for me.

I am impressed.

Cheers

Robert.

[Archive]

George Stephen replied:

Hi Robert,

an interference fit is made so that the inner part is marginally wider than the hole into which it is to fit. Sometimes this involves milling (like round a 5p or 10p) on the surface of the inner part. Force is required to press the inner part into the outer - bodgers use a hammer, but the proper way is to use a press - the nearest you're likely to achieve to this at home is probably a vice.

The inner part is thus held in place by the high friction between the 2 parts, without glue, or threads and nuts etc.

It seems that the machining of the hole in the ball and/or the diameter of the insert pin was occasionally less than precise (eg because the tools used had lost their edge, and not been re-sharpened), leading to the pin being prone to come out....

George

[Archive]

Robert replied:

Thanks George - those tools again!

I now have a BZP coach bolt that might do the job, a hammer and some glue. I'll try for a stainless one or a genuine part if I can.

Thanks again for your advice.

Robert.

[Archive]

Dan Edwards replied:

Hi, Sorry to jump on an existing topic with a new question.

Have just bought my first Dart, whilst rigging up at the weekend to check through i noticed that the mast rotated on the ball. With the shrouds secured it still rotated on the ball. Is this correct or should there be a friction fit to stop the mast rotating on the ball joint? If it is supposed to rotate are the shrouds just tensioned to secure it?

Any advice greatly appreciated,

Thanks Dan

[Archive]

Dartful Codger replied:

Hi Dan,
Yes , the mast IS supposed to rotate, as it forms part of the total aerofoil, obviously including the sail.
Without wishing to complicate the answer further (as there are many views on how tight your rigging should be for various wind strengths), in general, the rig should be tight enough (by tensioning up the forestay), so that the mast will still turn one way or the other without force, to about 70 degrees from centre. You should still then be able to rotate it a further 20 degrees by hand, when it will push against the shrouds (which are now wrapping round the mast at the top) to 90 degrees, or parallel with the front beam. A little lubrication of vaseline or similar on the top of the ball is also desirable to ensure it continues to pivot easily.

Paul Smith (Beaver S.C) 1961

[Archive]

Dan Edwards replied:

Hi Paul, Thanks for the quick response. Hopefully now i'm set to try it next weekend.

Thanks again

Dan

[Archive]

Martin Searle replied:

Folks,

Since I still have the mast down after going to the nationals, a bit of leakage in the hulls causing a temporary lay-off. I took the opportunity to look at the state of the mast step and the socket on the mast.

I have noticed in the mast's socket there is a piece of metal that has been pop riveted in and on mine this is very worn and the mast step metal insert has left a indentation in it and the pop rivets have been worn almost flat. On comparison with Kevin Dutch's mast which is a pretty new boat there is just a slight worn area on this piece of metal (it looks a lot thicker too!).

This looks like something that needs replacing during the off-season but can one obtain the right bit? What would happen if the rivets failed?

The mast ball is looking pretty worn too with the metal pin standing slightly proud of the surfce. Replacing that bit looks like a job for an expert.

This may all have a bearing on my forestay issues (see earlier posts).

Martin S.

[Archive]

John Long replied:

My boat, 1133, is 18 years old. Just before the Nationals I replaced the mast ball because it had worn almost flat on top and was very sloppy in rotation with excess movement. I bought a new Ball from The Laser Centre ( ?21 ) together with new non corrosive rivets. A fairly simple job to fix the new one in place , although a large size rivet gun is necessary.I also bought the small oblong plate which is affixed to the inside bottom of the mast and sits on top of the ball,held in place by two non corrosive rivets.Mine did not need replacing. If the plate is of use I can let you have it. Of interest,the six rivet holes in the front beam did not exactly line up with the new ball foot.

[Bob Carter]

Bob replied:

Hi Robert,
I suspect that you have to buy the whole ball but speak to Brian Phipps at Windsport. I had it happen to me but as I worked in Engineering I had an apprentice make me up a new one. It has to be a pressed fit & it needs to be domed on top. A half decent approximation is to go to the builders merchants and buy a coach bolt with a domed head that looks about the right size. Buy a few so that you can practice and also have a spare. You then cut off the head with about 15mm of the shank (shaft) left on the head. There is a square section close to the head. Grease it (as it is mild steel and will rust) and fit it in the ball. If it is a loose fit remove it when trailing to stop it falling out. If it is a tight fit then you are lucky so you can hammer it in using a soft drift. It will not come out when the mast is in place as it is trapped. I see no reason why this should not work as a long term cheap solution provided that you keep it greased and keep a spare in case it rusts or falls out when the mast is not on the boat.
Regards
Bob

I'm just resurrecting this item as it has come up again in a current thread (WaveyDavey's mast rotation one)
Cheers Bob

[Martin Searle]

Martin Searle replied:
<snip>
I have noticed in the mast's socket there is a piece of metal that has been pop riveted in and on mine this is very worn and the mast step metal insert has left a indentation in it and the pop rivets have been worn almost flat. On comparison with Kevin Dutch's mast which is a pretty new boat there is just a slight worn area on this piece of metal (it looks a lot thicker too!).
<snip>

This caused my mast to drop down by about 4mm or so (see Steve Willis mast article my one is referred to in that) anyway what had actually happened was that the indentation in the wear plate was actually hiding a hole pushed through the bottom of the mast foot casting by the pin in the mast ball being proud and my preference for a tight rig. I didn't find this until I tried to replace the wear plate and found this hole in the bottom.

Thus I had to replace the entire mast foot casting (easy and cheap to do btw) and this cured the mast dropping problem and allows me to use the pin in the bottom of the mast properly before I had to lift the mast slightly to put in a tent peg into it.

Martin S.