Bow plate looks "scary"

[allanbranch]

This is my project boat. Forgive me with using wrong terminology, feel free to correct me, I want to learn.

My bow plate look like it's in disrepair with cracks, see attached.

Replace or have a metal worker fix it?

Yes my boat is tied to the bow chocks, we're removing the cleats to paint the topside.

[Hydra]

What metal is it made of? Often, it isn't possible to repair cast parts.

Alain

[allanbranch]

How can I tell?

[Hydra]

If it's magnetic, it's probably steel. Else, it could be bronze or aluminium alloy.

You could scratch it with a file. Steel is much harder than aluminium alloy. Compare with scraps of metal that you know the composition.

Strike it lightly with a small hammer and could compare the sound you obtain with what you get on other objects. Aluminium alloy doesn't ring the same as steel.

But from the aspect of the traces of chafing on the starboard fairlead, it looks like aluminium alloy. Then, probably no possible repair.

Alain

[Red Sky]

Originally Posted by Hydra

If it's magnetic, it's probably steel. Else, it could be bronze or aluminium alloy.

You could scratch it with a file. Steel is much harder than aluminium alloy. Compare with scraps of metal that you know the composition.

Strike it lightly with a small hammer and could compare the sound you obtain with what you get on other objects. Aluminium alloy doesn't ring the same as steel.

But from the aspect of the traces of chafing on the starboard fairlead, it looks like aluminium alloy. Then, probably no possible repair.

Alain

+1 on the cast aluminum alloy

[Delancey]

Pretty sure it's cast aluminum. The best way to fix it is a function of what your goals and expectations are.

Do you just want to get out on the water and be safe but don't care what the repair looks like no matter how slipshod? Are you planning on doing a complete refit so that you end up with a beautifully restored nearly new looking old boat?

Need to answer these questions first.

[allanbranch]

Safe and functional, looks are cosmetic requirements are based on costs. I am painting the topside right now though.

[Sailmonkey]

That can't be repaired.
What I would do is to remove it, remove the tangs for the forestay, clean it, re-install it, and add a chain plate bolted to the stem that bends up and around this fitting.


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[Lepke]

Aluminum can be welded, but you could have a steel replacement made by any decent welding shop. Then have it galvanized.
If the boat builder is still around, maybe a replacement is available.

[puffcard]

Oxidized Aluminum melts at a much higher temp than the base metal so when you get it hot enough to develope the pool it melts into infinity. You have to get it very clean, white metal. This is some of the hardest welding to be done. Most of the time the welder doesn't get any penetration. So you grind off the broken parts, clean the rest and spray with a clear sealer.

I would pull that one off and have a SS one built with a bow roller. That's if you love the boat and plan on sailing pass the jetty.

[roverhi]

The fitting has already lost what is probably the attachment for the sail tack. The headstay puka is probably not far behind. I'd replace it. You could have a simple SS plate cut to the shape and have tangs welded on to replace it right now. Get some appropriate chocks and drill and tap them to replace the cast chocks in the original. If you wanted to do it as built, pull the fitting and send it to a foundry like the one in Port Townsend, WA and have them cast it in Bronze though it might be pricey.

[Delancey]

Originally Posted by allanbranch

Safe and functional, looks are cosmetic requirements are based on costs. I am painting the topside right now though.

Google "investment cast aluminum" to learn more about how the piece was originally made. Replacing with fabricated stainless would be Cadillac. Welding repair would be dubious.

Quick and dirty repair would be to sandwich the central tang with pieces of aluminum bar stock of the same thickness as the tang (twice as strong). Can get a short piece from McMaster Carr. Through-bolt through existing holes in tang if possible, if new holes needed drill them close to the deck to leave as much "meat" as possible.

Conversely, radius bottom edge of bar stock where it will fit against the inside corners of the tang where it meets the horizontal part of the existing part to leave as much "meat" as possible in the sandwich pieces. Drill new holes in sandwich bar stock for rigging attachments.

That's what I would probably do anyway.

Can you get some more pictures without the bow line obscuring that shackle? Presume that it is for the forestay, sort of a critical piece of the rigging. Presume the broken hole is for the jib tack, not so critical.

[brianlara 3]

ALLAN. FWIW...Cant see you buying a new one. And if it were mine I know I can fix it easily... clearly it is attached to the deck efficiently so no problems there.
That stem head fitting is made from cast alluminium. In essence that fitting performs two functions:
Primarily it's a forestay attachment...secondly it's docking line router, and is still OK in that function...cost a fortune to have a similar thing fabricated out of 316..
Back to primary function. The vertical section, which has previously snapped off at the aft most hole....reasons being eg alloy work hardens to start with and a loosish forestay will 'work' the alloy and snap it. Secondly...316 ss forestay attachment to an alloy fitting, add an electrolyte and bad must happen sooner or later.
Frankly it looks from the image to have been seriously under sized/engineered given that is a cheap casting having little tensile strength...especially where it is need most, to hold the mast up.
If it were mine today, apart from making a new one out of 316 which is a bit exie, I know i can fix it quite easily. First I would relocate the forestay temporarily, just get it out of the way.
Next, I'd take an angle grinder to the verticlt bit, cutting it and it's awful holes off completely and toss the scraps into the bin.
Now, after grinding, you are left with a smooth flat surface, yes I know it's curved, but it can take a curved plate of 316 ss on top. And Im suggesting, having only a few images for guidance, that about 1/4" plate would be right.
Presently the forestay is attached to alloy. Im my model it will be attached to piece of 1/4" ss welded vertically onto the new ss baseplate. The verticle part will have numerous holes drilled.
The present casting can stay esp as it it fitted well AND it serves other useful purposes.
Now you cut a template, a pattern, of the top surface, ant the pattern will come out to within app 1/2" of the fittings side verticles.
The new top plate will have neen rolled by whoever is going to weld on the verticle forestay piece.
The radius need for the correct "roll" you can trace by pencil from a piece of light cardbord held vertically athwartships. This trace will be the radius so must be accurate.
Once the plate is shaped, welded and drilled, ready for fitting, it can have it's mounting holes drilled and countersunk ready to take the existing bolts/bolt holes which will probably need to be longer.
This new top plate should fit like a glove and you'be able to pick the boat up with it....if you so desire !?!?
Between the prettily ground alloy plate and the quite inexpensive top plate will be (someones coice) something like Duralac. The GOUGEON BROTHERS (WEST SYSTEM EPOXIES) would probably seal it on with an epoxy bog and so would I but Duralac etc may be easier fot you.
Remember, it's the screws, 4 or how many? , that are holding the plate on.
The alternate to the above tiring ramble is to have a new e tire fitting fabricated from 316, in which case you' better love you boat heaps.
There, FWIW.
Were it it mine I can make this thing without leaving the boat but for you, couple of drawings/patterns made, not expensive.
Plenty of very capable on this Forum and so perhaps I'm about to be humbled. If so, graciously accepted...
Can barely see the keyboard so if errors forgive.
And the brain driving these eyes is considered by experts to be irreparable too.
Have fun Boy/Girl ?
Lara.
Ps cant edit, not poss.

[brianlara 3]

What Delancey said....dont alloy weld this thing.

[boatpoker]

Take it off, patch up the broken part with Bondo, look up "foundry" in yellow pages, have one cast in Silcon Bronze using the old one as the pattern for about $8 per lb. then take the casting to a machine shop and have it drilled. Total cost should be about $120 if you find the right small foundry.