400: Bow roller material - Lagoon400

[crayiii]

This is a known issue with several Lagoon cats, including brand new ones. They installed stainless components directly to the aluminum crossbeam with zero protection. Lagoon has known about this issue for years but they don't notify owners. If you contact them, they will ask for photos and will either send a kit to treat the corrosion or they will let you know you need a new crossbeam.

[meirriba]

Originally Posted by crayiii

This is a known issue with several Lagoon cats, including brand new ones. They installed stainless components directly to the aluminum crossbeam with zero protection. Lagoon has known about this issue for years but they don't notify owners. If you contact them, they will ask for photos and will either send a kit to treat the corrosion or they will let you know you need a new crossbeam.

As I mentioned several times, there is no corrosion.
And the base is certainly anodised aluminum not S/S. On L400 there are two identical units on the front beam and the second unit is there and it is clearly aluminum.
So in this case the idea of corrosion between dissimilar metals is misplaced.

[crayiii]

You have gone back and forth about what the material is made of. I've never seen a stainless crossbeam nor an aluminum bow roller. I've seen plenty of examples of the opposite though.

In any case, it sounds like you have it under control. Safe sailing captain.

[Sohum]

Originally Posted by meirriba

On L400 there are two identical units on the front beam and the second unit is there and it is clearly aluminum. .

What’s 2 nd unit? Please clarify. Unless it’s been replaced, the anchor roller.that doubles as a mount is aluminum. Roller sheave I’m not sure the OE material, definitely plasti

Name. Lagoon 400. Length. 12m/40ft. Manufacturer. Lagoon. Anchor roller on aluminium cross beam ...
There’s a good view in slides

https://www.ayc-yachtbroker.com/lagoon-400-1

Have a good day.

[meirriba]

Originally Posted by crayiii

You have gone back and forth about what the material is made of. I've never seen a stainless crossbeam nor an aluminum bow roller. I've seen plenty of examples of the opposite though.

In any case, it sounds like you have it under control. Safe sailing captain.

In the first two posts I have wondered about materials.
In the following posts I have made it clear.
Everything, repeat everything, both beam and roller bases are clearly anodised aluminum.

[meirriba]

Originally Posted by Sohum

What’s 2 nd unit? Please clarify. Unless it’s been replaced, the anchor roller.that doubles as a mount is aluminum. Roller sheave I’m not sure the OE material, definitely plasti

Name. Lagoon 400. Length. 12m/40ft. Manufacturer. Lagoon. Anchor roller on aluminium cross beam ...
There’s a good view in slides

https://www.ayc-yachtbroker.com/lagoon-400-1

Have a good day.

On the front crossbeam of our L400 there are (or in our case - were) two identical rollers.
One in front of the chain path, for the anchor chain. The other, offset to the starboard side, for rope rode, but too far aside to be used with the chain.
Both units of anodized aluminum with plastic roller.
I am probably going to have a copy made of the remaining one, with two side flaps to add more rivets and maybe two throughbolts (protected against corrosion by plastic sleeves)

[Sohum]

Cool. Please follow up when complete. Specifically wondering how you secure the unit onto the cross beams outer edge. Last yr I went to remove mine so a shop could fabricate a flared side plate (cheeks wearing thin). The fasteners are internal hex bolts, very tight access inside the beam. long story short, I put this on the to do later list.
Good luck

[belizesailor]

Originally Posted by meirriba

Yes

The metal assembly is (was in our case) connected to the crossbeam by 7 rivets.

These rivets broke while raising the anchor and the metal base with the plastic roller fell into the sea.

The boat is about 10 years old.

As I have mentioned, there are no corroded areas around the rivets holes except one hole that is ckearly enlarged.

The forward beam is aluminum. The bow roller base was almost certainly stainless steel. The rivets for a high load application may have been steel. Lots of different metals there. Almost certainly a galvanic corrossion issue.

[meirriba]

Originally Posted by belizesailor

The forward beam is aluminum. The bow roller base was almost certainly stainless steel. The rivets for a high load application may have been steel. Lots of different metals there. Almost certainly a galvanic corrossion issue.

As I see the second unit in real life and not theory, you are certainly mistaken.

[Spot]

Originally Posted by meirriba

As I see the second unit in real life and not theory, you are certainly mistaken.

Is is possible to post a picture of the situation? Then we can see what you are seeing and then we are more likely having the same conversation.

I am still curious about the failure mode.
Are bolts with locking nuts an option for replacing the rivets?

Moving the off-center one to center with better fasteners comes to mind.

[crayiii]

Originally Posted by meirriba

As I see the second unit in real life and not theory, you are certainly mistaken.

I've been searching for an aluminum bow roller for a year to prevent the crossbeam corrosion issue and have not been able to find one. On Monday I stopped at a large metal fabrication shop and brought my stainless bow roller assembly in and asked if they could make one out of aluminum. They said no because it wouldn't have enough strength without being much larger.

I really would like to know what yours looks like and where I can buy them.

[meirriba]

Bow roller, rivet hole

[meirriba]

Originally Posted by crayiii

I've been searching for an aluminum bow roller for a year to prevent the crossbeam corrosion issue and have not been able to find one. On Monday I stopped at a large metal fabrication shop and brought my stainless bow roller assembly in and asked if they could make one out of aluminum. They said no because it wouldn't have enough strength without being much larger.

I really would like to know what yours looks like and where I can buy them.

The original can be only from Lagoon, so you need a sort of contact there...
I am waiting now for an offer from a metal worker in Preveza, Greece.
If it will be to the point, I will post the details here.
Anyway, In my opinion there is no strength issue with aluminum base. The problem lies with the rivets (that broke, while the base was clearly intact!)
So, as mentioned above several times, we consider adding through bolts to make the connection of the unit safer.

[meirriba]

BTW, I have just passed next to newish Lagoon39, and its bowroller bases are made of S/S...

[meirriba]

Originally Posted by Spot

Is is possible to post a picture of the situation? Then we can see what you are seeing and then we are more likely having the same conversation.

I am still curious about the failure mode.
Are bolts with locking nuts an option for replacing the rivets?

Moving the off-center one to center with better fasteners comes to mind.

It is certainly one of the fastest options if a substitute cannot be made quickly.
Here is another picture of the ex rivets holes that show how clean they are and the elongated one clearly by side pressure.