Yes it can be straightened But when such material is forged (casted) the process requires cooling procedure or Stress relieving . The boom has been considerably weekend wind Unfortunately i don't believe there is any sort of cold bending of the parent metal (boom)that can produce a equal or stronger outcome.
Sure its not the dimple stretch illusion from the harness line wrapping around the "boom grip" material
Bend it back but don't go out to far ! I think the area weekend will become malleable and will bend again in a short period of time.

I have been thru consecutive ali booms now and and they don't seem to be going the distance.

Windxtasy said...

No optical illusion, it is definitely bent, but still useable.
Would I be better leaving it alone?

The short answer is "yes"

Windxtasy said...

Just noticed today my maui sails aluminium boom is bent on one side where the back harness line attaches.
Can it be straightened without it breaking?
How?

when you say bent, is it dented/folded ? or is it just out of overall shape?

dented/folded its gonna be a short life for it, short of cutting it open and rivetting an ali sheave in.

If its just a bit out of whack I reckon you could have a go at bending it back but bending alloy is never a good thing, it weakens it

The strength and durability of aluminium alloys vary widely, not only as a result of the components of the specific alloy, but also as a result of heat treatments and manufacturing processes. A lack of knowledge of these aspects has from time to time led to improperly designed structures and gained aluminium a bad reputation.

One important structural limitation of aluminium alloys is their fatigue strength. Unlike steels, aluminium alloys have no well-defined fatigue limit, meaning that fatigue failure eventually occurs, under even very small cyclic loadings. This implies that engineers must assess these loads and design for a fixed life rather than an infinite life.

Another important property of aluminium alloys is their sensitivity to heat. Workshop procedures involving heating are complicated by the fact that aluminium, unlike steel, melts without first glowing red.,, like all structural alloys, also are subject to internal stresses following heating operations such as welding and casting. The problem with aluminium alloys in this regard is their low melting point, which make them more susceptible to distortions from thermally induced stress relief. Controlled stress relief can be done during manufacturing by heat-treating the parts in an oven, followed by gradual cooling—in effect annealing the stresses.

Pay the extra wind Go Carbon next boom start saving and run the ali till i breaks.

busterwa said...

Yes it can be straightened But when such material is forged (casted) the process requires cooling procedure or Stress relieving . The boom has been considerably weekend

The material is extruded and yes I believe it must have had a "considerable weekend" and now it is bent

A mate's got a north skinny boom...it's bent like spaghetti, but he still pushes it around in big conditions. I bent a X3 a few years back, went to the carpark & straightened it on a mate's bullbar - lasted a while & never broke, but my confidence was shot. Got a 10yo boom that handles 110kgs swinging off it, keep wanting to retire it, but it's the only boom I have that fits a couple of my bigger sails.

Not an expert in materials, but in my view, the best (and likely) case scenario is that a single, unusual, and very sharp pull on the back strap of the harness line has caused this, but the boom is still structurally sound. Perhaps someone familiar with metals can confirm, but a catastrophic failure would feature "buckling", also called "beercanning failure", where the tube folds onto itself, and this doesn't look too close to it.

Edit: In retrospect, this is what Subsonic said.

I'd suggest monitoring this, and if the bend ever deteriorates with use, perhaps get another boom?

d1 said...

Not an expert in materials, but in my view, the best (and likely) case scenario is that a single, unusual, and very sharp pull on the back strap of the harness line has caused this, but the boom is still structurally sound. Perhaps someone familiar with metals can confirm, but a catastrophic failure would feature "buckling", also called "beercanning failure", where the tube folds onto itself, and this doesn't look too close to it.

Edit: In retrospect, this is what Subsonic said.

I'd suggest monitoring this, and if the bend ever deteriorates with use, perhaps get another boom?

I think the side in tension has had to stretch a lot so if it hasn't cracked a little on that side it would be pretty damn close. (Particularly given the temper applied to booms)

Absence of beercanning on the compression side doesn't mean it is good for use.
I would not risk using it


I agree with Mineral, Anita I didn't realise it was so new I'd hit up the supplier for a new arm. Still got that spare u can have as per P.M

You would think if I'd done something significant to that boom I would remember doing it! It must have been in that session at Safety Bay last Monday because I'd have noticed if the boom had been bent before.

The boom is nearly two years old I think

I bent an aeron 3 years ago, my mate bought it off me cheap, he is still using it, it hasnt bent further. He only uses it in safe areas though, always offshore but with a harbour wall over a mile away, usually people get resuced before they get to the wall.

Keep it for backup / rigging a second sail to leave on te beach. You can always swap booms over when you use the second sail.

redsurfbus said...

... he only uses it in safe areas though, always offshore but with a harbour wall over a mile away (ie 1.6km..), usually people get resuced before they get to the wall.

hmm - that sounds safe..