What's with fattening the mast?

Thread starter #1
I was away from the class for a dozen years and one of the rule changes that came to be during that time was away is the right to add a sleeve to the base of the mast to make it thicker and stronger (?). Could someone explain whether this is a go-fast deal (less slop and wasted energy), a way of making the mast last longer, or both. Should I be doing this to get more competitive?


Eric Woodman
Hey Eric,

I think there are a couple of different things going on here.

First, the new "rule" that you are speaking of is actually a change in manufacturing specs that is now being offered by Vanguard, this is a response to a problem with the newer masts bending...the “Fix” is to insert a 19” sleeve inside the lower part of the mast. All new masts are now supplied with this sleeve in place and an Upgrade Kit is available through any Vanguard dealer. If your rig is as old as your boat, or brand new last year, you should be fine…if the mast is 2(maybe 3) years old you should probably sleeve it.

The other aspect is wrapping the OUTSIDE of the mast where it sits in the step, to the best of my knowledge this has been going on as long as I have been sailing these boats (25+ years). Wrapping the base of the mast takes up the space between the mast and the step which helps stabilize the mast and eliminate the play. I have seen a ton of methods for this and the most common would be tape. One problem with tape is that it will wear over time and end up making a “Sticky Mess”…the method I like the best (so far) I got from Drew Staniar, he uses a sheet of thin flexible plastic – he rolls it up and inserts it into the step and then slides the rig in, works great and doesn’t leave any mess behind. I went to Staples and found a 3-ring binder with a flexible plastic cover, I then drilled out the two rivets holding the rings in place and I end up with one piece of flexible plastic that is about 21” x 11 1/2”. This size is perfect, when rolled up and placed in the step the 11 1/2” height just sticks out of the step by an inch or so (perfect for removing it later) and the 21” length works just right for my boat and rig (yours may vary)…remember you DON’T want to eliminate all the play, the mast needs to rotate while your sailing.

If you come down for the Spring Frostbite (starts a week from tomorrow) you can check out my set-up…and maybe even finally get you wind indicators back.:eek:
Wavedancer said:

That's an excellent tip. Will this method protect the mast tube from damage to the gel coat, if not worse?

Hi Jacob,

So far this method has covered all the bases....

First, it takes up the extra space and reduces the amount of play.

Second, It protects both the Mast and the gel coat.

Third, by filling the space it reduces the amount of water that can gather in the step during sailing. This is a minor gain but a gain none the less.

Also, because it is removable there is no danger of long term water damage. Over time water gets trapped between the tape and the mast and this can result in corrosion.
It is my understanding that Vanguard, to reduce inventory, combined the Laser and Sunfish masts to one size of tube. The tube selected is for the Laser which has a thinner wall than the original Sunfish tube. Therefore the need for the stiffener to prevent the lighter mast tube from bending when used with the Sunfish.
Isn't that ironic...considering there have been so many complaints about the quality of the US laser mast sections. People are going nuts trying to find Aussie extrusions and other, non-US sections because they think the US ones are weak.


Upside down?
Staff member
LAuman said:
THANKS! Hmm! $33. . . How many folks have bent/broken their masts while sailing? Might it be related to crew weight? BobF
As John Fonseca and Supercub reported, Vanguard introduced the mast sleeve because of complaints by Sunfishers with newer masts.

I believe (!) that the mast bending occurred during heavy weather sailing and I imagine that this would depend at least to some extent on how much boomvang was applied. I had an old (1979) boat with a stiffer mast to begin with and only heard about the problem from others.
It has been reported the change to the mast tubes goes back as far, possibly, as 1993. Those who race hard, vang hard, stay out in wilder conditions, or sail commonly in windy locales had ongoing, incessant breakdowns. There were a couple Worlds where much of the fleet bent their masts. The "rest of the story" only became known more recently, that the tube sections were changed and made the same for both lines, etc., etc.

If your mast tube is of the newer variety, you likely should sleeve the inside. Otherwise, no worries.

It won't do any good to bash anymore, as the fix has been determined, though we can wonder a little why it took so long to clear it up ...
Any creative solutions to this? Does the insert have to be the official $33 kit? The dia. required is 5.24 cm., and, it seems to me that it just has to stiffen the lower 19" of mast (and, maybe, not promote internal corrosion).
If you're racing, this is the only approved solution. If you're not racing, and perhaps day sailing, and not going out it big breezes, save your money. If you want to DIY, you're likely going to want to spend the $33, because by the time you take apart the cap on the bottom, you'll want to do it right so you don't have to do it again as long as the mast survives. They don't last forever, no matter what! If you're in salt water, they corrode simply because the gooseneck is not aluminum, the set pins are stainless, and other materials are dissimilar. Can't beat that game. And the wear on the metal from flexing (imperceptable in the mast, but trust me, it bends in heavier air), eventually causes it to fail.
Re: What's with fattening the mast?-Crew weight

Crew weight? I don't think so. I've seen Derrick Fries have one break. It was blowing about 15-20. Not crazy, but a nice breeze. He's not heavy by any stretch. Many others have had it happen, but I can't remember names right now.
Um. . . the "set pins". . . What are those? Perhaps they fasten the end caps? Our end caps were fastened with single pop rivets, and both of the bottom caps tore out.
As to the insert; with all due respect for class measurers, how do they know what's inside?
Original installation has two small tapered pins inserted on each side of the mast top cap and base cap to hold them into the mast. If the bottom caps came out, (tore?) the pins either wore way or were electrolyzed away, allowing the caps to fall out. If the masts are older than '93 there's nothing to do other than replace the caps, and I would still attach them with the set pins. Pop rivets stick out too far into the mast step that you can wear a hole in the step and start another problem. Caps at the top should be pop riveted, but I would use two so that the sheer load is balanced on both sides, rather than a pry load always in place on the one rivet.

When it comes to measuring, if it's apparent something has been done, an inquiry will be made. Someone who lies may or may not get away with it. However, some people in the past have made modifications to parts and to hulls and have been disqualified from major regattas for the infraction.

Part of this sport involves a sportsmanship quality that is difficult to quantify. Once a person earns the label of cheater, it's often difficult to shed. It's easier in my book to play by the rules, recognize and admit when I screw up or just don't have as good a skill, and try to get better AND have a good time doing it!

So, it's between you, your maker, and a probing measurer to truly answer your question!
Mast plug - We have a 2003 and a 2005. Both came ex factory with a single pop rivet, and both tore through the edge at the rivet and came out of the mast.
Insert - Point taken. . . Thanks.
Major surprise to learn they've gone to a rivet. Hopefully someone's monitoring this and will realize the tapered pins were used for 40+ years for a good reason. A single rivet will tear out--there's a big load on the caps, lots of leverage, and at a minimum two would be necessary; again the leverage though and the mast step wear issue would point me towards the pins.
Al, Gail, All you folks! I would really like to see a white paper on the S’fish mast and rig (a new bible?). I take respectful exception to your response on the legality of internal reinforcement of the mast. . . My remark about x-ray vision on the part of the measurer was an attempted joke (I STILL try to imagine expression in e-mails), and I have always observed the spirit of the rules in the classes in which I’ve competed. I point out, however, that there’s nothing in the Sunfish rules that I’ve read that refers to internal mast reinforcement - let alone requiring use of the manufacturer’s kit.
Also, I need to say that I have the greatest respect for Vanguard. . . They’re still alive and competitive and supplying quality products in a business that has had many casualties over the past 40 years. US dinghy sailors would be lost without them!
However, we have three 2003 or newer masts on which the factory-provided single rivet in the bottom cap failed messily – cap torn, mast step scored. To be sure, we take them out in whitecaps, under conditions in which even a Sunfish will plane. I e-mailed the dealer, and they'd never heard of a problem. I guess we need 3 rivets or “pins”.
The rivets DO stick out, but we’ll be using tape or the above-suggested plastic wrap around the mast. I see that APS lists a part # V79513 “boom cap pins”, and I guess that those are pins referred to.