MAST SUPPORT BEAMS

Joel Smith, Sonar, # 646

I have a new crack in no. 646's beam under the mast step. It's a "check" I suppose, rather than a crack, as it is horizontal and not vertical or diagonal.

Dana, JADE, #99

As part of #99 JADEs rebirth- I removed her mast beam and found two very large "checks" - minimum ten inches long from each from both ends. They were not visible until I removed the beam from the boat.

Mine was very definitely an example of the "iceberg" theory- that which what was visible- was only a small portion of the real problem.

The problem with the original beam, in my case, was- a single large piece of oak lumber that unfortunately had two very large knotholes. The knotholes were the source of the checking. There was no sign of any water damage from leaking decks, etc. (The numerous flaws were provided by Mother Nature, the cousins Pearson, time and stress.)

It is amazing that the beam still supported the rig.

I briefly considered epoxying the "checks" (or humongus cracks-) hesitated, and decided that there was a better way.

I have since fabricated a new beam from 1/2" planks of epoxy-laminated white oak. (Ferenc Maté gives pretty good directions for making your own deck beams.)

My new laminated beam is larger in all dimensions and is many times stronger than the original solid piece of lumber.

By the way, unless a previous owner has done something very extreme, the removal of the original beam is surprisingly easy.

The beam in my boat was held in place by two long vertical bolts thru the aluminum mast step plate. Also (4) 1/4" diameter hex cap bolts thru the beam and bulkhead. After removing the bolts- the beam came out quite easily. My beam and deck are not flattened out as yours is.

I was fortunate that when it came time to laminate a new beam I had two original beams that I drilled and bolted together as a form for the new beam. It became obvious to me that the beam from my boat was twisted like a pretzel. Upon clamping it with the other damaged beam they pulled each other straight and square. It was amazing to see just how close in size and shape the two beams were. One beam was from #80, the other from #99.

The double beam form worked great!

Oddly enough- upon unclamping from the form the new beam displayed about a half inch of spring back on each end. The surprise was- when it cam time to do the finish fitting of the new beam- it fit better than the original! Imagine my delight!

In your case you will need to restore the curvature to your deck. If it were me- I would put a jack under the beam still in place- and see if it was possible to move it up back where it belongs. I would go slowly and gently. If you can get the curvature back- you might think about fixing the rotted core in that area before removing the beam.

If that works- I would sister the damaged beam with a rugged piece of wood in order to preserve the curve, that hopefully, you have been able to restore. As I mentioned earlier- the original beam can be used as a form or pattern - so long as the shape is right.

Bill Bell, Kialoa, #41

The crack in Kialos' main beam was there when we met in l967 and it is still there today - no change. The boat has been sailing quite actively in the intervening period. Good luck

Chris Grundler, GULL, #704

My beam has bent or compressed due to deck delamination beneath mast step---the beam is now horizontal between companionway posts, rather than curved, and I may have some movement of the beam at the ends where it is attached at the hull). At this point I have removed step, removed rotten core, but have not touched the beam.

Mark Harrington, Ananke, #166

I just resolved my beam problem by replacing it with a tabernacle (stainless steel) that spans the distance between the two posts, but above deck. I had the "flat beam syndrome", and when I pulled it out, found that the depression in the deck around the mast step had allowed water to seep through the lag screw holes anchoring the step. The whole middle part of the beam was rotten, but not visible.

As Dana says, the beam is very easy to remove.

Celeste & Heather, Ebb Tide, #141

Knock on wood, but Ebb-Tide has a crack right down the middle of the beam, it looks like it has been there forever, never gets worse, and doesn't appear to flex at all. When we sailed Ebb down from SF, we hammered in a compression post just in case, but when I removed it I found it hadn't really been doing anything since the beam was still fixed in place. I suspect the original owner did some intense racing and probably stressed the rigging regularly to tune the mast.

Ray Alsup, Pegasus, #256

A modification made to Pegasus during her racing days was the addition of 2 heavy duty compression posts at the companion way leading to the foc'sle (the primary bulkhead). I have been told that this type of installation was common in the racing community during the late 1970's which would explain why it was made to Pegasus. Although the added support was good in theory, it lacked some basic fabrication details. Different grades of aluminum (none of which were marine grade) and SS had been brought together in an area subject to large amounts of moisture. The results of course was electrolysis and corrosion of a super magnitude that destroyed the weight distribution features and left the compression properties questionable.

I replaced the aluminum posts with a 2x6 inch mahogany post split lengthwise then shaped to fit snugly to the 3/4 inch bulkhead. The posts were stained, finished and attached using #12 SS machine screws on 12 inch centers from the foc'sle side. The aluminum weight distribution plate that had rested on the threshold was not replaced. The overhead SS bracing was retained however, it was covered with a padded bumper so I didn't have to wear a hard hat when entering the V-berth.

Mark Parker, #516, All Ways

I distinctly remember my first sail on "All Ways" after spending 3 years restoring her. It was blowing 20-25 and I had to use two hands on the tiller going to windward. I thought to myself, "What on earth have you done, sinking so much time and money into a boat that sails like this?!" When we got back to the dock, I hung a wrench on the halyard. It was nearly 4' aft or the mast base! I retuned the rig until it was exactly perpendicular and she sails beautifully.

My deck was cored under the step! (Step is mahogany.) I removed all the core and built up the deck so it is solid glass for about 2' x 3'. I sistered the original beam with 1/4" stainless steel plates on each side held in place by several through bolts and lots of 5200 (my beam will NOT be easy to replace for the next owner ;>) To protect my head from the ss, I covered them with mahognay trimboards. The result is SOLID.

Rob Squire, #96, Head Over Heels

Head over Heels is a west coast boat. Between the deck and the cabin liner which sits atop the beam was a large dollop of resin with filler. It was about a foot in diameter and supported the mast between the beam and the deck. My beam showed some signs of crush at the top, but no sags or cracks.

As a sidebar, my mast was moved forward 6 inches in the '60's. Sadly, the mast base rested half on the dollop and half off. The result was deck flex and cracking. Water damage occurred to the plywood bulkhead, but the beam seamed okay. Also, the mast movers added a second oak beam to the forward side of the bulkhead with knees parallel to and thru bolted to the original support beams. They all survived the water intrusion with no apparent damage.

My fix for the mess was to cut out an approximately 1 foot diameter section of deck at the site of the final mast step position. I used a Sawzall at a 30 to 45 degree angle to the horizontal to cut a pie pan shaped circle all the way down to the beam tops. I scraped out as much of the rotten bulkhead material I could find, then poured "Git Rot" into the remaining material. Using Epoxy and ropes of glass cloth strands, I refilled the gap between the beams, then proceeded to refill the opening with many layers (like 40) of weave and roving, all saturated in Epoxy. I built the opening up to the deck level, smoothed and finished the area with Brightside. The result was a step the seams like concrete when I jump on it. I have since driven the boat hard and see no signs of flex in either the deck or the beams.

My impression is that the beams are over built on some boats and underbuilt on others. If the beam is in okay shape, doesn't flex under load, fix the deck. If the beam is cracked and flexing, fix the beam (and the deck where it cracked). I've read that the only bulkhead required in the Triton is this mast step bulkhead, but the center section does no work. The sides carry the load to the hull via the support posts. If the center section of the bulkhead is trashed, I would refill it to provide an adequate spacer,

then tie the outer ends of the beam to the bulkhead with screws and glue.

Stephen

On Hull # 140 I made a cardboard template of the inside arc of the top of the forward bulkhead. Then I cut one 1/4" stainless steel plate and two pieces of 2" by 6" (as I recall) oak to that same arc.

Then I clamped it into place with a little tension from a bottle jack under it. Drilled and through

bolted it in place with stainless steel bolts.

Then I added vertical oak support columns thru-bolted on each side of the doorway opening in the bulkhead to support the beam.

Later sailed in 50 plus knots and fell off some serious big wave tops and as far as I could tell it never moved.

Bill Meyer, #393, Fjordia

Fjordia carries a forward lean in the mast right up until the jumpers. At that point it begins to rake back somewhat. Sailing in S.F. Bay in summer, I carry a permanent 1/3 reef, and the boat sails wonderfully with little to no weather helm. Carrying full sail however is a different matter. Reef early! Reef often!

I might add that in the summer along with the 1/3 reef I also carry a 100% jib. In the fall when winds are light I can successfully carry a 180 and full main with hardly any weather helm. All of this for whatever it's worth!

Allen, #158, KAHOLEE

I took a quick look at the mast beam section of the MIR, and it looks like KAHOLEE's solution is different, although I could have missed something. Her mast beam is a piece of stainless steel sandwiched between two pieces of hardwood. The stainless steel plate is mounted on edge, and attached to the support beams on either side of the cabin door. It is really quite simple, and takes advantage of the strength and lack of flexibility of the stainless steel mounted edge on to the compression. If you like, I'll be back in TorC next week, and I'll take

some pictures so you can see exactly what I'm talking about and send them to you.

Found this on the web site... http://members.tripod.com/~suter/improvment/maint.html

Gene Zaustlinsky (TALIS)

The deck-stepped Triton mast is supported by a beam which is bolted to the main bulkhead. It is only marginally adequate, we know of several broken beams. Check also that the deck has not been crushed under the mast step. The deck should be solid glass under the mast. This is not the case with older boats where this section is cored with plywood or balsa. A crushed section must be opened from beneath and filled with glass.

The original beam has a breaking strength of less than 1 ton; it is supported by a bulkhead good for more than 15 tons! Gus Moldestad, TALLYHO, U221, made up a new beam consisting of a sandwich of 1/4" stainless steel, an oak beam and a thin teak cosmetic facing. It equalled the thickness of the original. In my STARDUST, X39, my new beam is a sandwich of two 1/4" stainless plates flanking two 1" thick laminated ash beams. I also replaced the original four vertical bulkhead stiffeners with eight to center the beam under the mast step. The beam will be stronger if the ends are securely attached. I recommend bolting and epoxy glueing all component parts into a single, rigid structure.

It is essential to keep water out of the beam. If you have any holes in your beam, ream them out, fill with epoxy and redrill.

Several owners report good results with temporary "lally column" posts set up in place under the mast during races.

Larry, #607, Dogstar

Dogstar's previous owner had the mast raked forward, a fair dose of weight in the form of iron bars in the forward locker and the water tank full. Over the first couple of years I emptied out all that and removed the forward rake and Dogstar sails just fine. You just have to be sure to reef the main when the wind picks up. Reefing makes it go from strong weather helm to neutral helm.

Too much weight in the bow is said to make the boat hobbyhorse and that is slow.