General Info: Lagoon Cap Shroud Cracks!

[Gradient]

Originally Posted by beneteau-500

Z spa spacraft eurospa are all one in the same company,

if I had discovered suspected cracks the first thing I would do would be get a Dremel and a carbied bit and just lightly grind them to see how deep they are . If they are more than .015 deep and they continue to grow in length yes replace . But I have had the same situation on my beneteau 45f back in mid 90's and Found out the cracks where tool marks made after the casting the steel when they carried out machining them from the holding fixtures

I was a NDT inspector for 15 years and that is exactly my advice, many indications are just on the surface and will disappear after a tickle with a grinder. You can buy a dye penetrant kit from most welding supplies shops which will highlight cracks too small to see easily with the naked eye. If the indications are still there after grinding down half a mm then you could get it x-rayed by an NDT company but probably cheaper to replace!

[DavefromNZ]

We took the stay down today. On closer inspection we found nearly all of the swages/end terminals were showing some cracks but a lot were hidden behind the supports. I have attached a couple of picture of the dye testing.

Initially the rigger wanted to replace all. However we ground a crack down by about 1mm then did the dye again. There was no more crack. Here is advice we got from an experienced NDT tester:

Basically he has explained to me that when the material which the swages/end
terminals has been rolled then Forged that the material has been folded
over therefore making it appear that there is a stress crack showing, hence
once ground away the crack disappeared. We can also see further down the
forged eye where the material has been rolled over, however he said that
this should be visible down the entire length of the eye but it looks as
though this has been polished out in some areas. I showed him the pictures
of the dye test also. Unfortunately we cannot do an ultra sound on any of
the fittings due to there being a pressed toggle in the way and the open eye
end being swaged onto the stay.

I am still not too happy with the both the ends being swaged onto the stay
with a 7/8" eye swage onto 16mm 1x19 wire, especially when the chain plate
has a 1" hole, rigging screw has a 1" thread and the hole in the mast being
1" too!


The rigger was not happy with the strength mix between the wire, pins, swage. However I don't recall a Lagoon mast coming down and have to assume that the Lagoon engineers have it right.

Overall I decided that there was not a problem and had the stay refitted.

[arsenelupiga]

Good outcome !

How easy was getting mast back to fully tuned ?

Do you let riggers tune the mast or you tried to replicate exact original levels ?

Compare pics before and after?

Tightening shrouds beyond certain level only flexes the boat unnecessarily and does not add to stiffness. Finding that minimum flex point of max tightness not easy, i guess, esecially if one does not know structural parameters of the boat.

Boat must flex with more or less constant force to dissipate extreme wave force, it is my assumption.

[DavefromNZ]

I had the mast out at the end of last year to fit the Leisure Furl. I left it to the riggers to get the tuning right and will do so again tomorrow when the stay goes back on. There are black marks on the rigging screws so that should give guidance.

The rigger and I also wonder why the L450 has two rigging screws on the cap shrouds when one would have done?

[arsenelupiga]

Originally Posted by DavefromNZ

I had the mast out at the end of last year to fit the Leisure Furl. I left it to the riggers to get the tuning right and will do so again tomorrow when the stay goes back on. There are black marks on the rigging screws so that should give guidance.

The rigger and I also wonder why the L450 has two rigging screws on the cap shrouds when one would have done?

i was thinking that too. Same on 400. Only explanation I could come up with is makes it easier to put shrouds together as you can unscrew more 'meat'.

[Boatguy30]

Originally Posted by Boatguy30

Looks like a mark from the original tooling to me. Unlikely 2 fitting on different boat would have a crack in exact same spot. You can easily replace the top terminal with a sta lock long marine eye and double jaw toggle if needed.

The French love to mismatch pin and hole sizes.

[PaulinOz]

"You could get it x-rayed by an NDT company but probably cheaper to replace!"

May well be cheaper to replace if I can find something to replace it with.

The rigger confirmed that my part has multiple surface appearing cracks in it, that they should not be there on a 2 year old rig, it will fail at some indeterminate point in the future. The problem is not that Lagoon mismatch hole to pin size, it is they have mixed up pin sizes in the same fittings.

16 mm wire uses 25 mm pins in all the fittings I can buy or find the specs on. My Toggle connects to the cracked Eye bolt at one end via a 25 mm captive pin and connects to the swagged eye on the 16 mm wire via a removable 22 mm pin at the other. If both pins where 25 mm I could replace with other manufacturers parts.

Currently have a couple of people trying to source an OEM replacement eye bolt while I sit in a marina in Far North Queensland. It is not available currently in Australia so they are trying to find it overseas for me. The smaller turnbuckles on the rig are stamped "Z" but these large ones have no marks on them at all that I can find.