welded boom

[Aquah0lic]

I'm looking at a boat that has a major weld job on the boom right up by the gooseneck. Its definately a good weld, but is that good enough or should the boom be replaced?

Its a very long boom on a heavily rigged boat and the weld goes all the way around as if the gooseneck end was replaced or just broken off and repaired.

[Ex-Calif]

I'd let a sureveyor look at it.

The weld can be good or bad. Properly done a weld has better capability than the original material. The problem is identifying what is properly done.

Many welds fail right at the edge of the weld. Causes are many. Bad preparation, bad penetration, contamination while welding, wrong filler material etc., etc.

A common mistake when welding tubing is to prep the outside of the tube but not the inside. When the weld penetrates contaminants are drawn into the weld from the inside.

A weld can be inspected visually, with a 10X glass, with dye penetrant, with x-ray and probably ultrasonic and eddy current. X-ray is the most common.

Unless you know about the repair (who did it and whether they did a quality job) and have an x-ray of the weld done you probably won't know if it is good or not.

[Alan Wheeler]

The one good thing about welding with alloy is, it shows up those who can weld and those who can not just from how the weld looks. So if you think it looks really lovely, chances are it will be 99.99% a really good weld. There is still a concern however. Why did the boom break in the first place. Or is the gooseneck Ally and part of the Boom?? Whichever, I wonder why and or what broke it. It may have just been a worn part replaced of coure.

[Aquah0lic]

Dan, great answer, thanks for the input.

Alan, I don't know the story of how or if it broke but I'm going to see it again this weekend and plan to take lots of pics. I'll take a close up of the weld area and post it here.

[roverhi]

The weld in Aluminum has something like 70% of the strength of the unwelded alloy. That 70% figure is from memory so may be off by a few percent but there is a definite weakness at the weld. It has to do with the heat of the weld messing with the alloy matrix of the aluminum. For welding hulls, etc, it is no big deal as the overall structure is way stronger than it needs to be. Same with engineered aluminum fittings, they are overbuilt to compensate for the weakness of the weld. Welds in steel, on the other hand, are as strong as the material if done properly.

For a mast or boom, welding is not the usual way to repair or make them longer. Normally, a mast/boom is repaired by sleeving it and then mechanically fastening the sleeve to the outside tubing. If done right, that makes for repaired mast section as strong as the original. In fact, for masts taller than available extrusions, the mast sections are pieced together with sleeves. 1930's era 'J' boat masts were actually built up out of aluminum plate riveted together.

I'd question why the boom has been welded. It could be that the extrusion section was designed heavier so it could be welded. It's just that that really doesn't make sense as usually there is no problem getting a boom extrusion of the necessary length.

Aloha
Peter O.

[Aquah0lic]

As promised, here are the welded boom pics. It goes all the way around. The second pic is the underside. So, would you trust it?

[roverhi]

It's the goose neck casting that broke, not the aluminum extrusion. You've got an old roller reefing boom which are the spawn of the devil. Suggest you get a new issue internal reefting boom and ditch the POS, previously broken roller boom.

Mack Sails sourced a 15' boom for my P35 for around $800 including shipping to SF Bay along with a new main.

If you wanted a replacement roller boom, you just missed mine. Kept it laying on the dock for more than a year hoping someone would walk off with it. No one did so I cut it up and recycled it a couple of weeks ago.

Aloha
Peter O.

[Ex-Calif]

The good news is the weld looks sound from the picture and the weld looks old so it has been holding up under use. It's not the prettiest weld as it is pretty uneven but it looks well penetrated and fairly clean.

Further good news is the cherry rivets holding the boom to the goosneck look tight. Loose rivets might disply dirty streaks from under the heads.

I guess it's a matter of degree.

If this is the same boat you are posting about in the Galaxy 32 thread you've got a lot more work to do than worry about this boom.

I personally wouldn't take on a project this big but I don't really know your goals. We have worse looking boats in daily use around our club.

[Aquah0lic]

Hey Dan,

Yep, its the same boat and yep, its a project. I am only considering it right now because I can get it VERY cheap and it has a certain old school charm that I like. It seems a shame to not rescue her.

I looked at a Rafiki 35 the other day and this boat is rigged as heavy or heavier than the Rafiki, so I assume it is blue water capable.

As for the roller reefing boom, the mail does not roll inside the boom like on a furling mast, it just flakes on top, so I don't understand what a rr boom would be.

[roverhi]

Roller reefing booms were de riguer in the '60s and earlier. Never have been able to figure out why as they were totally idiotic, slow to tuck in a reef, required expensive hardware, created a very poor setting sail ruining the sail in the process.

At one time, there was a crank that went on to that square pin on the gooseneck. You'd rotate the boom with the crank rolling the sail around the boom. It resulted in an extremely poor setting sail with a tight leech and very baggy mid section. All the downward tension on the sail was concentrated on the leach which could ruin a sail in one reef by stretching out the leach. Since it made for a baggy middle, the sail produced excessive healing forces and drive just when you didn't want or need it. In short, it was an invention that did what it was supposed to do extremely poorly and was expensive to boot.

Your boom and sail has probably been converted to slab reefing and the roller system is just baggage now.

Aloha
Peter O.

[Alan Wheeler]

I would also be more concerned with the internal bearing and shaft of that thing.
The original damage has been done by some serious force exerted on the boom in the wrong way. I think it would be too difficult making a new Goosneck fitting seeing as that gear box unit is so long. It might be worth looking for a second hand boom.

[Aquah0lic]

Very interesting... so, was the boom used for furling as well or just reefing?

Also, on a seperate topic, I layed down on the settee to see if I would fit and looking up at the underside of the side deck, there was a hand sized area where I could see light. Not a hole that I could poke my finger through, but like looking up at an old glazed over skylight. Is that from missing gelcoat or a thin spot in the glass or...?

[roverhi]

There is what looks like a perfect specimen of your goose neck fitting on eBay (eBay # 250069655733). It would probably be way cheaper to replace the gooseneck if you can get it out of the extrusion. Worth a look.

Roller reefing was reefing only. You still flaked the sail on the boom and used a sail cover for stowing the sail.

Another problem with Roller reefing booms was attaching a vang when reefed. They made a horseshoe shaped coller that you could slide on the boom after you reefed and hook a vang to. BIG problem was this collar rested on the sail material. Wonder how long it would've taken to abrade holes in the sail.

Aloha
Peter O.

[Cheechako]

Looks as if that fitting may be a casting... if so, it would be very suspect having been welded. Welding aluminum castings is an art for sure and often not real sucessful. I would guess an unintentional jibe did the damage. The smaller diameter being the weak point. Must be some way to reuse the old boom with a new gooseneck....?

[sandy daugherty]

Odds are that hand sized translucent area is a glassed over hole of indeterminant purpose. If theres no cracking around it, and it looks OK on top, You could use Sandy's Flashing VCR fix: one layer of black electrician's tape.