Too much downhaul on too stiff a mast = break?

It is very unlikely that too much downhaul caused it to break. Unless you were going for broke with a winch and even then you would more than likely tear the sail before you broke the mast.

I have broken a few masts, and the one non-formula mast I broke I noticed a crack in it a few days before. I wasn't surprised at all when it broke, and it was under almost no tension as I had only started to rig the sail.

The correct mast can make a big difference to the way a sail rigs. It can make it too full or it can make it too flat, both of which will end up feeling bad. The bend-curve can make a big difference as this varies a lot between brands.

i see from a previous post that yours broke at the ferrule. these masts are incredibly resilient in flexing through downforce, so I doubt it split simply because you put too much downhaul on it. more likely the mast had developed a weak spot from accidental impact. while the mast can withstand being bent to an alarming degree (well past what an aggressively downhauled sail can), give it a sharp blow with a ball peen hammer and you can easilly shatter it.

Have a look at this mast under unusual load...
www.peconicpuffin.com/the_peconic_puffin/2010/07/mast-stick-in-the-soup-good-photo.html

That is the classic sign that the mast is about to break. Rig feels spongey and you cannot generate any power, especially when pumping.

Make haste for the beach or be prepared to swim.

i have snapped a few masts and am fairly certain that they broke due to miss treatment out of the water.

If you are going to invest in a new or second hand mast and want longevity from i would highly recommend RDM, have not snapped one yet.

Mast will bend, i was fairly impressed when i saw the photo below of the flex in my mast purely from pumping.

SDM =Standard Diameter, RDM =Reduced Diameter.

I had a rigging accident last week. Snaped almost new 400cm RDM, I used it only few times :(
It was my fault, I downhauled it and it seemed a bit hard to pull, then I heard a snap. It broke at the bottom on the top half of the mast, I guess when I put it in my sail, it separated a bit and I didn't notice.
Thank god I bought it on closeup for just 100€ and that I had a spare.

I believe it wouldn't snap otherwise, because it was very flexible mast.

If the two halves aren't properly together then its pretty likely to break. Makes a lot of sense to tape the join using electrical tape as it's easy for the halves to come apart a little while you're rigging. Plus it keeps the sand out so it doesn't get stuck.

Not an expert but from what you said you we trying to get the leech floppy, I've learnt that the little flops between battens are less on a wave sail from pics I've checked out. Wave sails generally top 2, Freeride sails have them down to around the 4th batten, and racing sails just about between every batten to the the boom!

I'm like you, I freaked out when I started to downhaul and then some to get that flop. But it's reassuring to hear from others that it is OK to give it shirtloads.

Another thing that got me paranoid is the gap that can appear between the top and bottom parts of the mast in the ferrule. Many I've read snapped there or pinched the luff sleeve and holed it. I've taped mine with black duct tape and still checked by feeling around the luff if they came apart. It's one advantage of the old one-piece masts. No ferrules to break, you just had to put up with the weight! Simple is good.

What everytime after you have put them together before you put the sail on?

The top half of the mast may have been developing a crack on one side at the bottom edge.

if you are a lazy bugger like myself,feed mast thru sleeve without tape, when thru sleeve nearly to top of sail go to boom cutout and push mast up from LOWER section of 2 piece mast , first checking that mast is properly joined.

the mast then cannot come undone as you are pushing bottom section all the way to top,it's pushing the top section of the mast up the sleeve that's when it separates.

Thats how I managed to sail several km's offshore before the mast went bang! LONG swim home. That was mast breakage number 6. You'd think that I would learn from the previous 5.

Top section crack at base.. will post pics later.. hopefully going sailing now.. had to work yesterday.I'll use the 2nd hand mast I cut the bottom off.Im pretty nervous after last sail..I'll tape the join..Hope it all holds together as I cant afford to buy one!

^That looks as if it has had tape around it to hold together an existing smaller crack at the edge.
i have had masts start to develop a crack in the same spot and to prevent and wrapped a couple of sheets of fiber glass around it to stop it ending like yours did.

The tape was just some Id put there because I misunderstood a forum post & thought you needed to tape around the bottom of it for some reason.. Now I realise the post meant to tape it together when you rig..