Build new or fix mast...?

[midiman]

I have a 4 inch 16 foot sitka spruce mast. It belongs to a 14" catboat from the 30ties (http://www.woodboatblog.com/). It snapped right above deck (3 feet). The material is in pretty good shape. Now I am looking for some advice and thoughts:

Fix Mast:
My idea here: Strip the mast, fix surface and cracks, "splice" the bottom mast back on by "in-laying" about 6 triangle shaped oak strips. I was thinking about 6 feet long and 1 inch deep.

New Mast:
Order $400 worth of sitka spruce and start from scratch. Shape tapered square, then to 8 sides. Belt sand it to a round 4 inches. Also mount 2 in-mast pulleys for the rigging.

Thanks

[PAR]

You can repair the mast, but you approach seems flawed as I understand it. Placing a hardwood Dutchman into soft wood will create hard points and stress risers, which will accelerate a failure in the same location. The repair should be with a similar density wood (white pine or sitka), have generous scarfs (12:1 or better) at both ends, which are well staggered about the stick.

[midiman]

Thanks... That makes sense with the wood types. My background is machine engineering and there it is is much less problematic to mix materials.

Let me see if I understand you correctly. Scarf a new 6 foot piece to the old mast. Would a scarf like this work?. Then use epoxy?

http://www.woodboatblog.com/pics/mast.jpg

[alan white]

I've fixed a few masts by splicing, including my own fir mast recenty (actually adding three feet to change to keel stepped from deck stepped.
I used a 10:1 scarf, and the whole job was very quick and predictable.
First, use a wood very similar to the existing, as PAR says. Secondly, do nothing to the cracks in the mast--- you will do more damage filling them than doing nothing. Mast cracks are normal.
Here is how to scarf the mast. Measure up from the highest damaged point 10 times mast diameter (a little over 3 ft for you). Add to that measurement the length that would complete the bury down to the keel. Perhaps this is another 4 ft.
A power plane will be handy for the next step. To taper the upper (existing) mast, and do it straight, will require skill. I do this part by eye and finish with a hand plane, but you may find it easier to make a saddle for the mast and a pair of straight hardwood runners to each side of the cut. The runners are angled so that viewed from the side, they are exactly parallel and show only the part being removed.
Once set up, power plane close but slightly (1/8") above the runners. Then, using a hand saw (a japanese saw is what I would use), saw down until the saw teeth barely contact both runners about every two inches along the length of the cut. Now, using a hand plane, remove down to the saw kerfs. Set the plane very fine, working down towards the sharp end. At the last, plane in short strokes across, angleing the plane to 45 degrees or whatever allows the plane to rest on both runners.
Once the mast part is done, the new stump is cut to the same angle. This is far easier, since the piece is shorter.
I put the new piece on square and dress it round after it's glued on.
Many spruces besides Sitka will do for the new part. Eastern white spruce would be my choice. This piece should be a laminated glue-up. I would suggest using four thicknesses of 2x6, so you end up with 5 1/2" x 6".
Square that after glue dries to 4 1/4 "x4 1/4" x a bit longer than the finished part. You want to start with an extra 1/8" all around if possible.
Here is where a jointer comes in handy. The piece is sawn to a taper and if you have access to a jointer, you can run the piece through of not too long.
Test for straightness after smooth. If the angle's off, you rest either the heel or the tip on the after-table of the jointer and work your way that way to a perfect angle. Once it's right, glue the piece on. It may want to slip downward, so drive a couple of small galvinized nails into the upper mast and cut the heads off 1/8" above the surface. That will cure any slippage.
I use either epoxy or gorilla glue (PU glue leaves a more invisible line). Epoxy, if a little thickened, will fill any irregularities.
Use straightedges, string, whatever to line it up perfectly.
Afterwards, eight-side and sixteen side the stump and then go easy, checking frequently with straightedge.
Finish with a sanding belt (60 grit is good) cut to a strip and wrapped around, pulling down with each hand alternately. Then sand with the grain to your heart's content.
The mast will be as good as new (at least at the bottom).

Alan

[alan white]

And regarding that picture, no no no... a simple inclined plane scarf! There is such a thing as a "clothespin scarf", but for your little mast, just make the joint a long diagonal.
oh yes--- and don't forget to fit the two original broken parts together and make measurement of original length!

[alan white]

Here are a couple of shots of my own mast. You are looking at the top of the splice. This mast is fir. The wood used was a 4x4 from home depot.
Cost was about ten bucks. A weird thing happened when I scarfed this mast. The grain width (which I had attempted to match) lined up so well that it almost looks like a single piece of wood.

[midiman]

I figured I was looking for a way too complicated solution. Thanks for all that great advice....

So after all....hypothetically..... if I was to build a new mast. I am trying to find detail information on Sitka Spruce and/or Douglas Fir. Besides the Spruce being lighter and more split resistant are there any other important factors?

The mast is 16 feet and 3 1/2 inches and has 2 "in-mast" pulleys. The price ranges are somewhere from $300 to $450....

Thanks

[alan white]

When you say 'in mast pulleys". I assume you mean peak halyard and throat halyard sheaves that lie within slots, assuming this is a gaff rigged catboat mast. The wood used to build the original mast may not be Sitka spruce either. If I were to be duplicating that mast and wanted a good reasonable substitute to sitka, I would use fir. It's a little heavier, but many traditional boats have fir spars. Making a solid new mast is very easy. Fir can be laminated out of several pieces, and the cost should be far less than your $300.00.
I would say a stack of five pieces, 5" ripped to 4 1/4" or so and planed to about 13/16" each would cost about $100 at $3.00 a board foot, all clear vertical grain.
Your original mast may or may not be tapered, depending on the designer's whim---- some small taper is okay on a gaff rig mast that uses mast hoops, and if it uses a sail track (the track is more typical if sheaves are in a slot, a more streamlined and race-conscious design), the mast can be tapered quite a bit more. I don't mean the second taper above the hounds, but the lower taper.
A built-up mast is superior to a single piece stick, as it will not crack and therefore will be a bit stronger. If the old mast has taper, and the taper is curved, make sure that the aft face is straight--- all the curve should run up the forward side.
The reason you might see solid one piece masts on character boats is that they look more traditional---- but again, they are generally weaker. People do have money to throw away, you know.
If you use gorilla glue, as you can see from the pictures, the joints don't show like with epoxy. If you also stain the mast, especially with a gold filler stain, it will be hard to make out the joints at all.
If you need advice as you do the job, just ask. A power plane is a huge asset, if you own one. If not, for $150, you should get one for this job.
If you have a mast track, you have the advantage of doing this:
Build the mast in two pieces that are temporarily screwed together with the screws later hidden by the mast track. After sanding to round (but not finish sanding), take the two halves apart and hollow the mast, leaving the area of the hounds and below the boom solid with about 3/4" wall thickness (this can be done by running the flat face, several passes down askew across a table saw with a long support and a friend helping). A near perfect circularly concave trough will result, and a short section can be used to test/adjust before commencing).
A hollow mast is very strong, as almost no strength is supplied by the core of a mast. the boat will heel less and mast raising will be easier, especially if you are feeding the mast into a hole in the deck, which is the case with most catboats.

Alan

[midiman]

Yes... all these terms. I wanted to restore a boat and not learn an other language. :) They are peak/throat halyard sheaves and the mast tapers only up top. Oh yes and it uses hoops that I have yet to make. Now I also have a good excuse to buy an other cool tool. TNX

Now there is only one question... The quote I got for clear vertical grain Douglas fir (C&better) 16 feet long is $7!! There has to be an other supplier in the North Carolina area but I cannot locate one. Do I need a road trip up north?

[alan white]

This sounds like a lot. Many lumber yards stock vert. grain fir for use on old floors, at least around here. But you are asking for a larger size than they are used to selling. If you went with 3/4" pieces (six in all because 5 gets you only 3 3/4"), you are talking common stock prices. By the way, I have a dynamite way to make mast hoops if you're interested, using ash.
Sure---- drive up here. But really, you might keep searching. The Chesepeke area would have boat wood sources galore, I think. Then there is the Bristol, RI. area. And around Cape Cod, a lot of boatbuilders.
I am always amazed at how hard it is to get some woods down south.

A.

[alan white]

Correction, midiman. I thought your mast was 4". You're fine with 3 3/4" pieces, 5 of them, making 3 3/4" x 3 3/4" to start. A quarter inch over is fine.
Common Eastern white spruce is also a good choice. This is what 2x4s are made of. However, using 2x thickness will guarantee curvy pieces, as they are kiln dried and have a lot of built-up stresses that show up when the wood is ripped. Straight knot-free spruce boards would be good, but if you can get fir, it is nearly always better stock.
Spruce, around here, is no more than a doller a foot. It grows everywhere.
Knots are the problem. And if you can find three nice clear (or nearly so) 2x6s 16 ft long ($30.00 total), and plane them to 1 1/4" each, you are really doing well. Stay away from sappy pockets, shakes, and dark knots. Small (1/2") light brown knots are just fine.

[midiman]

Building my new mast is done. It is 16 feet long and 3 1/2 diameter. Douglas fir and plenty of gorilla glue. The final material cost was under $200. Many thanks to Alan White. :cool:

[alan white]

Looks great! Now you're eying the boom and gaff...