This is a second time the bar on Dakine harness and then new bought failed in one year.
Did somebody tried welding this staff ( stainless steel
) or new replacement bar is the only option?
BTW I am disappointed a bit that without any spectacular reasons
this pieces are cracking that easy.
In such case harness bar by Dakine should be called consumables.
is that really a DaKine bar? doesn't look like any DaKine windsurf spreader bar I have ever seen before.
I'm pretty sure thats the NP quick release bar. i had three break in exactly the same spot. It's a design fault IMHO. I now dont use a NP harness. The point where it cracks is just way too thin
I have now snapped 3 Dakine spreader bars through fatigue (never during a catapult funnily enough) although in their defence I am 94 kg's and sail some pretty rough conditions so the bar is constantly being quickly loaded and unloaded as opposed to a steady loading sailing flater water.
Where the hollow main bar has snapped (once) just next to where the hook is welded onto I haven't bothered trying to repair as the wall thickness is too thin, but where the hook has snapped just past it's weld point onto main bar I have repaired (welded) successfully. Having just bought a new harness I also now have two spare (repaired) bars.
BTW Macroscien, to the best of my knowledge that is not a Dakine bar as Bender and Aus301 have pointed out.
Yeah, NP bar.
I had one break the same after about 12months but it was in a horrific catapault in 35kn - ended up with the harness turned around (hook on my back) and pretty much sore everywhere 
so I'd not blame the bar for snapping.
Hmmm now I have read the above, and have a new bar maybe buying a spare is a good idea just in case
Mine all failed within the first 3-4 uses. Mine was a seat harness and i was sailing fully powered up with bigish sails 7.0,7.8 and 8.4m RSR's.
I'm not into brand bashing as the NP harnesses are very nice. However they have designed this part of the bar incorrectly and it's a potentially dangerous accident wating to happen if you continue to use these harness bars. When they snap (and they do) you may be catapaulted and having a sharp piece is steel stabbing you inthe guts, face, sail and board will not be fun.
It can be welded with tig 316 stainless no doubt but you may need to place an insert into the joint to strengthen it.
I've tried to weld stainless spreader bars before and they always failed near the weld very soon afterwards.
There's something about welding that makes the stainless brittle. But I'm no welder, and an expert may be able to do it without this happening.
Agree with Buster, u can tig that but will need an insert to add the strength it needs as well as the fact it is so thin, the weld will become stronger than anything around it though and if u are paying anyone to do it u might as well buy a new spreader bar!
You can't weld an insert inside, or a plate on the outside, to strengthen it
The way the plastic bit fits on the outside and the other plastic bit goes up the middle leaves no room for added stuff 
Otherwise I'd have had mine done already.....
I was going through 2-3 a year to snags, they don't make them like they use too.
now I use a 12 year old one I had laying in the Shed and its still going strong
.
We (windsurfers) are lucky bunch that if something fail there is not too far to soft landing.
I will be more careful in choosing right gear being para glider , -parachuter even kiter that could fly higher and more often then we do.
Now I need to make a hated trip to the shop knowing that stuff you are buying is going to brake, just a matter of time, later or sooner.
Or should I try to replace just the bar with another type and made quick release on the belt somewhere ?
Unless NP will come with some idea how to modify that bar history will likely repeat itself.
a kite bar is a bit more robust. i know the hook looks a bit different but the one i used for a while was no more difficult getting in and out of the lines for me. unfortunately the rest of the harness was heavy and uncomfortable. if u get a kite bar, you might need to change to slightly shorter lines
possibly worth a try if you keep busting them?
as already mentioned, the alloy bars seem to last longer. I broke a steel spreader each season for a while (2 x dakine and 2 x np, and always right next to the hook weld) and i'm under 75kg. I've been using this current alloy spreader for a couple of years now. unfortunately they seem to be hard to find
p.s. macro - a slim healthy chappy like you doesn't need a quick release
North harness bars seem to be excelent I'm a really fit 110kg an they hold up really well for slalom sailing, and I'm definitely not a light sailer, however I have had a seat harness that completely tore off while I was sailing, the stitching was pretty ordinary tho, brand new harness that got ripped off
