Two Bolts Or Not Two Bolts...That Should Not Be The Question

A friend had his rig and board separate in the impact zone recently, which got me thinking about my longstanding choice in mast feet and how it would be a good topic for the Peconic Puffin to tackle (or muck up.)   Let us sing the praises of the two-bolt mastfoot, which I believe to be superior to the one bolt mastfoot without exception or qualification.   There have been plenty of debates on the topic (and as a gearhead I have followed them all) but I believe there is a clear answer that is right for everybody.  (I must be a jerk to believe that, yes?  So if you're playing at home, please reply with why I'm wrong ASAP so I can learn something.) 

Anyhow here is my reasoning:

1.  (The big one.)  A two-bolt uni is far less likely to separate from the board than a one bolt.   The first time I saw rig separation I was a mile from shore, sailing about 100 yards behind a friend in 4.0 conditions in heavy chop.   All of a sudden he was sinking...I thought "what a lull!" (He was on a sinker).  But actually his board had shot out from beneath him when his mastfoot slipped out of the track.   A gust picked up his board and tossed it 50 feet downwind, from where it proceeded to continue away from him.   Fortunately I was there to sail to his board and stop its escape.    Most single bolt slip-outs can be blamed on the sailor (didn't tighten the mastfoot enough, didn't wash out sand that was holding the foot in place giving the illusion of a tight fit etc) but...do you want to blame or do you want to keep your rig attached to your board?  There is also the rare breakage of the mast track nut (I had an industry rep once tell me "it never happens".  I told him my story of the nut from my WSH mast foot cracking in half (happily I was on the beach.)   With two bolts, if you've somehow failed to tighten the thing and one of the bolts somehow manages to slide out your rig will still be attached, and you'll notice the flopping long before its possible for the second nut to slide out.

2.  You don't have to remove the mast foot in order to roof rack or bag the board.   Just pop out the uni joint and leave your mast foot where it's presumably dialed in for the board.   Speaking of which,

3.  The two-bolt mast foot does not limit your useful mast track range.   How can I say this when the two-bolters most definitely limit the extreme forward and backward range?   Here's how:  I was lucky enough to have a conversation with Peter Thommen, master board builder (Bjorn Dunkerbeck's board builder in Bjorn's heyday) about mast tracks and the proper position to set the foot of a mast track.   Thommen said that mast tracks offer way more range than anyone should use, that they are as long as they are because they need a long mast track so there's enough material to attach the thing strongly to the board.   He said for any given windsurfer on a given board there's only about 3 cm range of mast track adjustment that benefits the board and rider no matter what sail is used on it, and that board designers center the mast track around that ideal area for an average sized windsurfer.    I found this a revelation at the time.   Thommen continued "so if you ever are out on the water and find the board seems to be sailing in perfect balance, mark that spot, and never move the uni more than 3 cm in any direction from it."        If he's right (and having played with this for years since that conversation I believe he is) then all any of us need is about an inch and a half of range.   Unless you find that you own a board that is only dialed in when the mast foot is jammed all the way forward (or all the way back) for one sail (in which case if this theory is true then all your sails should be rigged way forward or way back on that board) there's no reason to need all that range.   For myself, I own two boards that I sail a lot of sails on ("Candy 77"...a 77 liter freestyle wave, I sail from 3.4 to 5.5, and "Calamity Too" a 109 liter freestyle board that I've sailed 5.0-7.0) I've been able to dial in with two bolt mast tracks.

4.  If you own several boards, you can own many mast feet bases but fewer unis.   We have 6 boards total (all with two bolt bases) but half as many unis.   The newest uni is reserved for wave sailing, the oldest for nonplaning freestyle in the creek, and a "middle" uni for any non-wave sailing (if the Mrs. and I are sailing together she gets the wave uni because NOTHING IS TOO GOOD FOR MY WIFE!)

I know two people who were rescued by boats a mile from shore due to rig separation...they could not swim fast enough to catch their boards as they blew downwind.   That will always underscore for me the best reason to choose two bolts over one.

(Photo:  A Chinook two-bolt mast base.   This one features a rubber U-joint.  I prefer the tendon...some other folks opt for the mechanical joint.)

Comments

[Bunty]

Do you know I didn't even know that 2 bold mastfeet existed!

[Ned]

Nice Micheal,

I had that base separation thing happen to me back in the Gorge in about 1989...back in the day. It was scary and I managed to reconnect but it was like a wrestling match with cork that would not cooperate. I like your reasons for 2 bolt bases and agree....little I know.

Hatteras was good for me...15 days sailing straight. Did ABK and sailed 12 days after. Back on Hudson now, off to Tinyo's 2nd June for "instructor trainer" course, then 16th June start at American YC. So I will miss 7 June Hecksher Freestyle event.

How was ABK at Napeaque? I plan on doing ABK this fall. Still van shopping.

Ned

[Catapulting_Aaron]

I've always sailed 1 bolt, but after reading this I'll probably convert. If you sail in very safe places with lots of shallow water, then I could see an argument for 1 bolt, though.

Thanks for posting that Thommen comment. I've often tried to "overtune" with mast track position with poor results so that explains a lot.

[g-42]

Re. "NOTHING IS TOO GOOD FOR MY WIFE!"

Wow, you're really working on those karma points - that ought to be good for a hallpass on a windy day ;)

Not sure I agree on the two-bolt deal. If you look at the whole setup and figure out potential failure points, the 2-bolt setup eliminates (or reduced risk) of failure at the bolt/nut level; unfortunately, you've just introduced another failure point right above it with that little retainer clip arrangement keeping the base plug in the plate. Similarly, the Euro pins don't give me the warm fuzzies, either, but that's a different story (and those have come a long way since the ones that separated or broke on my buddies and me in the late 80's).

In most applications, the way to test this would be to look at failure rates on the different kinds of setups over a sufficiently large population, statistically correcting for different use patterns and such. And given the small size of our sport, we'd never get anywhere near the large numbers to come to any sort of conclusion (either on the population or the failures). So it's all conjecture, anyway.

One more reason I don't like the 2-bolt is the slightly elevated position of joint. It's not much, but when you're using race gear, you definitely are looking to lower the pivot point, not raise it.

-Andreas

http://g-42.blogspot.com

[Michael]

Good points, Andreas! Unfortunately the statistical evaluation you suggest (which would be great) ain't gonna happen. I've never heard of the retainer clip coming undone (or otherwise failing.) But single bolts sliding out of the mast track? I've heard over a dozen stories.

I don't like the europins either...I use the chinook cup.

How much elevation does the twin bolt add? My guess is 1/4". Perhaps for racing (where there are lots of people around you, and presumed hyper-focus on gear set up before you hit the water)a single bolt offers an advantage in that regard.

[giampaolo]

Good topic.

In 26 years of windsurfing I never personally had a single bolt mast foot sliding out of the mast track... I must have strong hands! Those few times that it did get loose a bit, it slid forward (like it is supposed to naturally slide) and forward it can't come out.
It did happen to me to have a bolt (the brass kind) cracked, but fortunately on the beach too. Since then, I have a spare bolt in my harness pocket (together with a spare line and the car key).

Anyways, no doubt that the two bolts kind is safer from this point of view.

Still, I prefere the single bolt because I have more than six boards and I continuosly try out more boards (got a lot of friends...). I need something that is quick to screw in and out and it would honestly bug me to have to own a base for each single board I use.

And now let's talk about euro pin or american double clip system...
I really don't trust the euro pin, since that can detach in the waves.
So I use a double clip UNI, but don't like the Chinook one, since it's plastic. Once I broke the tendon and my spectra line (I always replace the safety line with a spectra one...) teared right thru the plastic of the tendom ends like it was butter.
So I bought a Streamlined one, that has the top and bottom parts (where the tendon is attached) in metal. Unfortunately, the plastic cup of the Streamlined sucks (the holes of the clips get ovalized) and it was the cause of a couple of breakages of expensive carbon extensions.
So, I now replaced that cup with a Chinook one. In other words, a hybrid with the best parts of both.
Will never understand why Chinook does the tendom ends in metal only for the europin UNI and in plastic for the double clip...

Sorry to be so long, hope somebody can find this interesting. I better copy this and save it for that post about UNIs that I always wanted to do and never did on my blog...

Oh, one more thing... I always remove the top of the chinook cup (the one with those two little screws). What the hell is it for? To keep the water in so that it will rotten the clips? Plus without it, I am able to acces the clips in case I will need to do that in the water... that happened too.

Cheers!

[Bruce]

I have had 2-bolt chinooks (for many years, probably around 15) its the one area where I have never had a problem. Basically requires 2 points of failure, bolts coming undone, threads stripping, even mast box failing. Even if both bolts are loose and the base slides its unlikely to come out. Rock solid, I would recommend them to anyone.

[michael]

Great reply, Giampaolo. A few thoughts on your thoughts:

Carrying a spare nut is probably not a bad idea for single bolt-ers, but there's still the problem of losing your board downwind during seperation (and the difficulty of reuniting board and rig in the kind of conditions you might encounter.) Carrying spare line is a must.

While sliding a single bolt base on and off a board is easier than a two bolt base, with a little practice the two bolter only takes 30 seconds longer to do.

"Once I broke the tendon and my spectra line (I always replace the safety line with a spectra one...)teared right thru the plastic of the tendom ends like it was butter."

Wow! Also, I never considered switching that line out with Spectra. But why not!

"So I bought a Streamlined one, that has the top and bottom parts (where the tendon is attached) in metal. "

I've got Streamlined unis in a Chinook base myself.

"I always remove the top of the chinook cup (the one with those two little screws). What the hell is it for? To keep the water in so that it will rotten the clips? Plus without it, I am able to acces the clips in case I will need to do that in the water... that happened too."

My only thought about that top piece is that it may help keep the cup from deforming under load. Though whenever I lose the top piece I don't bother replacing it.

[James]

Michael- You make a very persuasive argument for 2 bolt bases! I may just have to switch soon. But I do some have reasons for liking single bolt...

I've always used single bolt bases because they're a little cheaper and simpler and there are fewer parts to lose. Especially since you don't have to buy a separate base plate for every board.

Also, I think what Thommen says about not needing the whole range of mast track tuning only applies when the sail type, size, and age are closely matched to the board. For less upwardly mobile windsurfers who acquire used gear in a piecemeal fashion, that is rarely the case. For example, if I want to use a pre-1998 board with a post-2000 sail, I may need to put the base at the very very back of the track to get it to work right, which is only possible with a single-bolt base. Additionally, if I am using old mistral boards with adjustable mast tracks, and I lose the mistral pin or don't want to use the crappy mistral extension, I can still use them by screwing a single-bolt base into the alternate hole of the carriage.

Regarding failures, the only thing I've ever had happen is the base slide forward in the track when I didn't screw it in well.

[michael]

James...at last! (note to readers...I reached out to James for a comment because he can really bring it technically...click on "James is Crazier than I am" in the right hand column to see!)
First of all, you can move the plate from board to board, but it will take you 30 seconds more than with a single bolt uni. And you're not going to lose either piece any easier than you'd misplace an entire single bolt unit.

It is true that a board ten years old or older, combined with a sail made in the last few years, will often sail best with the sail jammed all the way in the back of the mast track. I'd suggest that when you're on that gear combo that you pay particular attention to the health and attachment of the uni.

[F Messina]

Nice well thought out essay. I must admit I am a Streamline two bolt user. I like that I can leave the base attached all the time with no bulk, and attach the tendon uni when I sail. Three weeks ago after a great Crab session I came in to discover that both my bolts were loose on my base. All that had happened was my base had moved forward 1/4 inch. Thank goodness for redundancy.

[Mark]

I'm definitely with the two bolt system. But interestingly most of my single pin failures have been with pin shear at the top.

I regularly hear of boges failing at the point where the metal goes into the joint. The bummer about that failure is that it tends to be catastrophic and sudden so even inspection beforehand doesn't spot the danger. Also the webbing can be useless in such circumstances.

I'm using Chinook at the moment and they have a single piece of machined steel top and bottom and the protective rope goes from machined steel to machined steel so even if the tendon was to hyperspace completely away there would be a sailable connection between sail and board.

[atx windsurfer]

Last year, when I was getting a rig together to learn to windsurf, I agreed with the argument of the two bolt. I also hated detaching a sail with the 1 bolt after a long tiring session, my hands were just too tired to really pinch the pins in to release the sail.

However, after 9 months, I think I am the first and only one at my local lake to experience a board separation on a 2 bolt at the clip. It was a 15-20kt day, I was on an 8m with a Techno Formula. I had sailed for more than 3 hrs without problem, and I know my clip was clipped in properly. On a failed jibe, my foot slipped somewhere near the mast base. And if it was by some miracle that my big toe could have declipped the mast base, I should have bought a lottery ticket that day, but my sail came right off of the board. It was a tendon joint, so it did take about 15 minutes of swimming to try to attach it back in. Fortunately, it was an 8m non cammed sail, and not enough water could get into the luff to sink it, like some of my wide luff cammed sails.

I asked the other windsurfers around, many have been sailing for 10-30yrs, and no one can say that they had the same experience. I am hesitant to use my 2 bolt, but perhaps I just need a new mast base plate. I did get this one used.

[the editor]

So the piece that prevents the clip from retracting had to be disfunctional (permanently depressed) for your foot to be able to push the clip "out". That does seem like a ten million to one situation!

Of course it's no argument for a single bolt base...I see someone have their single bolt slide right out of the mast track about once per year, for whatever reason (not sufficiently tightened, or loosened by a hard landing or wave abuse etc.)

I always check my plate to verify that the retaining piece is doing its job...I've never had to adjust it, though I do take them off the boards and rinse them off at the end of each season.

In any event, glad to hear you made it back in one piece!

[MikeC]

I have seen a couple ways that the singles fail that have not been discussed. I bought a used board that had a mast track repair! I must have tightened on a high or crumbly section of the mast track repair itself. You can guess the results.
The other is that I must have had sand or something jam inside of the uni (total neglect) and the thing unscrewed itself and came off the board mid air. One could ask well how could you unscrew it if you are going back and forth doing the same type of gybes/tacks? The answer is that while learning I only made the port tack gybe as the starboard tack gybe was in the rougher water and would result in a crash so at some point the "unscrew" tack won. 2 bolt all the way ,streamlined deckplates and replaced the screws w/ a 3mm hex head screw which also fits the batten hex head so the tool is carried aboard sail at all times.

[Michael]

MikeC, for tightening the twin deck bolts I prefer using the built in wrench in the bottom of the uni. I'd be worried that the batten tool would break before I got the bolts as tight as I like them.

[Keith]

Anyone with any common sense, even non-windsurfers, can clearly see that the two bolt chinook with the "hourglass" shaped rubber u-joint (like the one pictured at the top of this page) is BY FAR the best to use. It does limit the range of adjustment slightly. But if you need that much more room to move the base fore or aft, then something else is very wrong with your setup. Another minor issue is the extra height and SLIGHT loss of added rigidity. But unless you are racing for money (and we're really splitting hairs here) this is so miniscule for the average sailor to worry about. I have one particular two blot base and u-joint that has served me well for over 15 years! All my boards have their own base which stays on the board, and i have two joints. Never a single problem with any component. The guys sail with swear by the single bolt tendon but every year, at least one of them has a breakdown. And when I started sailing I had two of the tendons tear out of the cup. For me, It's simple math.

[Mark]

Dear All,

We've just had a death of a windsurfer in offshore conditions and we think the most likely reason is board / rig separation resulting in the participant being unable to paddle back home. We can't tell for certain but his board was found 1.5miles out to sea.

As it stands I have been unable to get any furhter information on whether there was a deckplate in it / or bolt or broken deckplate or some such other combination and I haven't been able to get any information on his kit in his kit bag.

He was sailing in a very tricky location by himself but he was a good sailor and he was doubtless pressed for time because his family needed him back to his house so chose ultimately the close but dangerous beach.

Manual decoupling as a result of sail failure may have been the reason for rig and sail not being together.

Please be aware that I have seen far more boge failures where the metal comes out of the rubber section (webbing then ineffective) than any other failure.

Next to that is single bolts just unscrewing themselves.

Sorry guys but take care from what I can tell from this site you guys really sail in very similar conditions to us. Strong rips / waves and offshore conditions in secluded beaches.

I'm like Keith each of my boards has the double in the board which stays in the board.

I just think its miles safer than anything else I've seen.

[joe]

My issue with the single bolt mast bases has always been that it was difficult to remove when my hands were cold and/or i was tired. I try to take good care in ensuring the parts are all good, functioning and TIGHT. So, I have been contemplating the two(2) bolt plate for some time. This article made me realize I actually have a safety feature on my most used mast base. It is a piece of plastic protruding from the protector plate that goes next to the board. [img]http://thumbs4.ebaystatic.com/d/l225/m/m8pQPN8cPx-GU503G8Mx43w.jpg[/img] When i put the plate all the way back i put that protrusion at the back and that way the base cannot slide out. Perhaps i should put it in the track in that fashion all the time ?

In any case, the one time i had a sail come off the board was on the local river with my Fanatic CAT and home made mast base adjustment - to be able to use the pulleys. It came apart and i was in the middle of the river. It took me 15 minutes to put it back and i drifted under the bridge. Someone had called the fire department and so I quickly sailed to shore before any more drama occurred :-)

These types of articles are NEEDED. Safety is always under-rated. As i told a fellow windsurfer - whenever i sail alone i carry a cell phone in a water proof bag. He sails with a dry suit and never thought of that before ...

Me too, believe strongly in metal bases !!!

THANX again
joe windsurfer
http://joewindsurfer.com

[Olderwindsurfer]

Very interesting comments. I have both 1 and 2 bolt. I have not had a separation since the early hour glass used to break. I have never had an issue with a tendon. Overall I've have had more issues trying to get the pin in and out of a 2 bolt base, and when is it too worn to continue using? Nothing wares on the 1 bolt. I have had single bolts come loose, due to careless installation, but they slide around and I use the deeper not that has plenty of thread, so just a trip to the beach for an easy fix. I have also not got the pin quite seated on the 2 bolt which is much more dangerous. I'm still on the fence.