Leaky Mast Step

Thread starter #1
Hi Folks!

About 10 years ago I went sailing in a really, really strong wind :eek: It was actually way too windy and just about all I could do was go with the wind and then, gradually climb back up to my departure point. I did this several times before I was exhausted (my sailing buddy, who weighs 200 pounds, cancelled out on me when he saw the wind!)

Anyway, as I recall, my sail stretched that day (I actually heard/saw it happen!) and I also had a rigging problem somewhere along the line. The long and short was that I ended up upside down in the water resting on the bottom of my boat for some time. (that was when the people on shore called the Coast Guard - but that's another story) :rolleyes:

The waves were big and ever since that trip my mast step started leaking water. I think what happened is that the cunningham was a little loose and the mast might have come out of the step a little bit and then the rocking of the waves might have cracked the step somewhere...

I decided to re-investigate the issue today and what I found was that the step doesn't leak at the bottom - it leaks further up. That is to say, water will only drain to a certain point and then it remains. Given that the problem seems to have happened on 'that' day it makes me think the step might be cracked further up and that the rest of it might be OK.

If that is the case, can I just make a hole (ouch) and the wrap the step in fiberglass? I'm trying to decide what to do with the boat and I don't really want to spend a lot of time doing major re-construction so I'm hoping it will be a more simple repair given how it happened. Anyway, I took some pics (before cutting a hole!)

Also, my hull number is ZFSA 4786 M82D - if anyone can tell me what that means I'd appreciate it too!


Yes, it does sound like have cracked the mast tube. It is a pretty easy fix, you'll want to put in an inspection port, wrap the tube with 2-3 layers of fiberglass mat/resin (and possibly the base of the tube as well, since you are in there.

The following thread gives you a good idea of where to cut the hole - there are a number of additional threads on here about fixing the mast step (it's usually the base that lets go), use the search feature and search on mast step repair


The hull id number tells you where it was built, the sail number and the month/year it was built. You can decode it with the info here :
Thread starter #3
Hi 49208 ~ thanks for the reply :)

I'm encouraged, I'll get an inspection port and take the plunge :eek: With repspect to the serial number, mine seems different then the ones in the FAQ...

ZFSA 4786 M82D

ZFS: Performance Sailcraft
A: Sail Number 104786 ??
M82D: ???

I'm not sure what to make of it :confused:
You have the manufacturer and sail number - the last 4 are a little harder, for sure the 82 was the year of the build, and guessing either March or Decemeber was the month.
Thread starter #5
I'm thinking maybe it's this;

ZFSA 4786 M82D

ZFS: Performance Sailcraft
A: Sail Number Starts with 10 so it's 104786
M: August
82: 1982
D: ??

Dave built it? :D
For sure, you are correct with the builder and sail number Marvin. My boat is a similar vintage and though I'm not particularly worried about it, the last four numbers/characters have always perplexed me:

ZFS 98617 M81G
Builder: Performance Sailcraft, Point Claire, Québec
Sail Number: 98617
Year: 1981

Based on your reasoning, my boat was also manufactured in August and was built by 'Gertrude' :D
Thread starter #8
If anyone is monitoring this thread I'd love to have some 'real world' advice on my mast step issue. I was thinking it would be cool for advice on a step by step basis (pardon the pun) :D

I managed to pick up a 5" Deck Plate (Inspection Port) and I got one with a clear top :) It cost me a whopping $9.99 CDN

I then cut the hole and stuck in the trouble light. There was trace water around the bottom front of the tube. Putting more water in the step caused it to some out fairly quick through the bottom :-0

Just as a refresher, the reason for opening it up is not that the step is broken or loose but that it leaks. The depth of the whole is pretty close to 14.5" so I assume there's some wear on the bottom of the tube too.

Is the next step removing the old Bondo? If so, what's the best way to do that?


If you are sure it's leaking at the very bottom, then you should create (pour) a new bottom. Search the threads here, you basically need to clean out the bottom of the inside of the tube as best you can, then literally pour resin (add graphite powder if you desire) to form the new base. You aren't adding a lot, you usually only need 1/4" to 3/8" to seal the existing leak and make it solid.

As far as the donut on the outside of the tube, IMHO, it looks in pretty good shape, I wouldn't remove it, just dry the area thoroughly, rough it up with a grinder or sandpaper and then lay down a couple layers of fiberglass mat to tie the tube to the hull. Gouv has a pretty decent how-to on his site here:
Thread starter #10
Hi 49208;

Thanks for the guidance :D

Originally I thought it was leaking farther up but when I removed some of the donut it became clear that it's leaking in at least two places - at the bottom of the tube and also in a couple of places about .5" higher up the tube...

My guess is that the turning action of the mast in the tube slowly wore out the bottom. So that appears to be one leak...

If I shine a trouble light towards the front of the tube inside the boat and then look down the tube from above I can readily see that it's very 'thin' at the lower front of the tube. In fact, if I run my hand around that part of the tube I can easily feel it.

My guess on those leaks is that the front of the tube is probably also prone to wear because the mast is usually loaded (bent) towards the rear of the boat causing the bottom to exert pressure on the lower front of the tube. Why they are higher up though is beyond me.

At any rate, it appears that I have more then one leak :mad:

The good news is that I have most of the donut removed on the front :D


Thread starter #12
Thanks Kaiser ~ I saw your thread and enjoyed it.

I've never done fiberglass work before - do you know specifically what West Systems stuff I need and also what fiberglass I require when the time comes? :eek:
I had only done it once before myself - with limited success.

I basically used three mixtures:
1) The first mixture was mostly epoxy with just a little bit of high density filler and colloidal silica (I don't think I really needed the CS - could have just used the filler) to thicken it up to a honey consistency. I just poured this into the bottom of the donut to fill in the space below the mast step tube and set the depth of the tube (i.e. how far the mast would stick into the hole)
2) Epoxy plus a lot of filler to make a peanut butter or toothpase-like consistency. This is what I smeared in around the edges of the tube to really cement it into place
3) Epoxy with no filler - I put this into a roller paint tray, soaked the piece of fiberglass (I mostly used the 4-inch wide fiberglass "tape" - which is just a roll of 4" wide fiberglass) in it, and then pulled the piece of glass between the tray and one of the yellow flexible spreaders to get the excess off (so you wind up with a piece of thoroughly wetted-out tape - but no excess, dripping epoxy)

Unfortunately, it's really hard to see how I laid the fiberglass down in my pictures because it's clear and it blends in with what's behind it really well.

Here's an excerpt from an email reply I gave someone else who asked the same question about what products I used.... I went West System all the way. It's expensive - but it works really well:

I used a single quart and had a little bit left over. Note that the last letter in the part number for the resin and hardener is a size code and they match up - so you use the -A (quart) resin with the -A hardener, -B (gallon) with -B and so on.

Check out the how-to page for West System here:http://www.westsystem.com/ss/use-guides/
Here are the basics that you'll need:
#105-A Epoxy Resin, Qt.
#206-A Slow Hardener, 0.44pt.
#300 Mini Pump Set
#404 High Density Filler
Fiberglass tape and cloth

Oh - and definitely a lot of acetone and rubber gloves.

Other cool stuff to have:
#808 Flexible Plastic Spreader
Their little plastic stir sticks and mixing tubs (can't find the numbers)...
Thread starter #14
Hi Kaiser ~ thanks for the additional info :D

With respect to the 404 High Density filler - it seems to come in a variety of sizes.
15 oz & 43 oz (and more). How much would be appropriate?

Also the 808 Flexible plastic spreaders come in 2 packs or 12 packs - how many of those should I get?

I'm getting closer... :eek:
The 15oz filler should be plenty. I'd get two 2-packs of the spreaders.

BTW - just a disclaimer... I'm no expert at this... I design electronics for a living. I just read the West System information at the link I provided, made some judgments/guesses about how I wanted to go about the repair, and went for it - and so far it's worked out fine. Also, I was mostly concerned with strength and ease of repair on a pleasure-only boat - I gave no thought to saving weight or class legality.
Thread starter #16
BTW - just a disclaimer... I'm no expert at this... I design electronics for a living. I just read the West System information at the link I provided, made some judgments/guesses about how I wanted to go about the repair, and went for it - and so far it's worked out fine.
Hahaha - up here we call that CYA - and I don't mean Canadian Yachting Association :D

No worries, I'm in the process of trying to gather the 'right stuff'. I'm in agreement with the desired result and just needed someone to tell me what I need from West Systems.

I know zip about this stuff and didn't want to walk in the store and walk out with all the wrong material only to get home and have to go back etc. Thanks much!
I just finished (I think) my mast step reinforcement/repair. After getting all the old gunk out of the joint between the step and the hull and thoroughly drying everything, I started filling with west epoxy. Then I chopped some glass and filled the void to flush. I then put a layer of glass mat around the bottom of the mast step and added three inch wide by about ten inch long strips of woven glass down the step and about 5 inches out inside the hull. I kept adding strips until a had built up about 3 layers. It was about 15 pieces all together. I think I have it plenty strong now. I brushed the epoxy onto each piece of glass before I stuck them in the boat, then I used my fingers and the brush to work out any air bubbles or voids.

I like your idea about adding 3/8" of resin inside the bottom of the mast step. Is West system#105 w/#206 hardener the correct product to use for that? Will it get hard enough to still let the mast rotate freely or will I have to add an aluminum or teflon disc?

Barometer Soup
Thread starter #19
Even though I have no direct experience with this (yet!) in my research several people mentioned that you should not seat the mast directly on top of the epoxy because it doesn't want to turn.

One fellow actually broke something (boom vang bracket?) and as a result he created a policy of epoxying a stainless disk in the bottom of the tube whenever he did a mast step repair.

Just a confirmation for you :D