Sitka or Fir masts??

[Columbia 112]

Sitka Spruce or Fir? To build new spars for my Rozinante I asked for a quote on materials from a timber supplier on the Island, the Spruce is 1500$ CND and the Fir is 1200$ CDN. That’s for wood that's planned to thickness and cut to width. Which do I use? Just as an aside the Spruce came from a log that was 29’ long and 7’ in diameter. The mill usually supplies temple builders on the other side of the Pacific but they also like to help out in special situations like mine.

Ross

[Nicholas Carey]

Douglas Fir is a bit heavier than Sitka Spruce. But, it's also stronger and stiffer.

As a result, if you build hollow spars, you can safely reduce the spar's scantlings by 10 to 15 percent if you use Douglas Fir and wind up with a spar that's that's about the same weight, strength and stiffness as th equivalent hollow spruce spar.

VG fir looks nice varnished, too.

[Bob Smalser]

Fir.

Sitka is way over-rated.

DF is stronger and stiffer. Depending on the application, you can often reduce the spruce scantlings by 10-15% and achieve the same result at almost the same weight. And have durability to rot, to boot.

[David W Pratt]

I've heard that modren sitka is not the old lowland stuff tha never had a big snow load.
Don't know.
Thrth's spars are Douglas Fir, bird'smouth, hollow.
Ilove 'em.
The builder first assembled the mast with two opposite joints unglued, then when the other glue had set, he opened the mast and installed the electrical harness and finished gluing.
Good luck.

[Jay Greer]

I have built two Rosinantes in my time. And I am currently building masts for an H 28. L. Francis Herreshoff himself liked fir for making stiffer masts in larger boats. However, the Rosinante has such a small rig that the strength in spruce is sufficient and the lightness of spruce is a plus. When in doubt follow the designers suggestion.

[Billy Bones]

Great jagged jones that's a lot of money for spar stock, especially from your own back yard. Yea it's been a while since I built my spars but still. Good luck, anyway. Aren't they supposed to be cheaper than aluminum? cuz, adding in a starvation wage for yourself, they won't be.

Wow. Good luck anyway.

[uncas]

I sense that fir is probably a better choice. Am not familiar with it myself.
Mine happens to be spruce...If there are a couple of things to say in its favor...
1) my mast is roughly 60 yrs. old...and still in good shape
2) After my yard dropped it from an full upright position to the deck...nothing really happened to it...okay, a few nick, some delamination at the base but...Even thinking about the force of hitting the cabin and then the deck...makes me quiver...! :eek:
So two pluses..May not be the best reason...but I can't say that spruce is over rated.

[Columbia 112]

Like I said, most of the stuff goes to the other side of the Pacific to build temples and the likes and they pay very very well. On the way to work I drive by a saw mill everyday and see ship loads of Yellow Cedar timbers that would make you cry. But I can't buy any of it for love nor money because it's all going over there. I calculate that the spruce is close to 12$ CND a BF finished, and the Fir isn't far behind,ouch!! I may try to contact some small private mills on the island and see if I can work a deal.

[Billy Bones]

Oh, and so my post isn't completely unhelpful, I meant to add that mine are douglas fir and I am very pleased with them.

Thanks for the explanation.

I'm toying with making my next ones out of spanish cedar, just 'cuz; appropriately sized to account for different characteristics.(slight) I'm becoming a big believer in trying to use what grows locally, at least to the extent convenient. Mahogany is ubiquitous here but just too heavy.

[ 11-10-2005, 05:45 PM: Message edited by: Billy Bones ]

[Don Kurylko]

12 a board foot for Sitka Spruce! Yikes! :eek: West Wind Hardwood has rough, kiln dried, VG Fir listed at $5.25 to $6 / bf. smile.gif http://www.westwindhardwood.com/

[Canoeyawl]

I like Sitka spruce; the engineering numbers indicate that for a given weight Select spruce should be stiffer than Douglas fir and weight aloft is everything.
There are many deviations in a species and Fir may be more readily available in select grades. I have found a lot of difference in weight of either wood by going through big piles trying to high grade for spars.
They used to sell Sitka Spruce in the S.F. Bay area as “std”, “ladder grade”, and “aircraft grade” You paid accordingly!

Some specs from the Gov. handbook, Wood as an Engineering Material
DouglasFir, Sitka Spruce
Specific gravity .45 to.50, .37to .40,
Static bending
Modulus of rupture psi 7,700-12,400, 5,700- 10,200
Modulus of elasticity 1.56 to 1.82 million psi 1.23 to1.57 million psi
Work to maximum load
In.lbs. per cu.in. 7.6 –9.9, 6.3 –9.4

[kc8pql]

I got enough VG Sitka to build a 50' mast, spreaders, two booms, a 12' bowsprit and enough left over to make a wisker pole and a radar tower for $5.80 bd. ft. plus about $100 shipping from Public Lumber in Detroit. Nice stuff. Very little grain runout, straight and the ring count averaged more than 30 per. inch. I'm in Ohio. Around here, Sitka is like Bigfoot, rumored to exist, but nobody's actually seen it. I'd think where you are you could find a better deal.

[ 11-10-2005, 07:46 PM: Message edited by: kc8pql ]

[BirchBark]

So what would be a good choice for wood on the East coast? Baltimore area.
It would need to be something in stock as it would be for a small boat and not alot of BF.
Anyone have any good boat lumber yards I could go to?

Thanks,
Chris

[ 11-10-2005, 09:18 PM: Message edited by: BirchBark ]

[Zimmer]

The British Navy couldnt get enough long leaf yellow pine for their warships. Thats what I would use.

[Bob Cleek]

Well, I agreee with both Greer and Smalser, but I'm going to side with Greer on this one for the following reasons. Sitka spruce has the greatest COMPRESSION strength of anything around and that is what you want in a lightweight spar. The Roz is a rather light boat and anything you can do to reduce weight aloft will be a great plus to her sailing performance. Finally, it is difficult to find good Doug fir these days. It's around, but at a similar high price. "Old growth" is scarce. It isn't really "old" that matters, but rather "naturally grown." "Second" growth Doug fir is "farmed" or at least "nurtured" to grow fast and produce a product quickly. The result is a wide grain and softer wood. Fine for construction grade dimensioned lumber, plywood peelers and pulp, but not for fine boat work. I'll bet Bob has a ready supply of really good tight grained Doug fir laid in. You will probably not be so lucky. What tips the scale for me is the weight issue on this particular design. If you were building a big hulking heavy boat, I'd say go with the fir for the reasons Bob cited.

It is a shame that the good timber is going to Japan. Don't kid yourself by believing that crap about their building temples out of it. That's just a bunch of politically correct PR. They figure that people will figure that it is going to noble cause. What do you think they are making those sake boxes out of? Mmmmm? They use it for all sorts of woodworking purposes, including plywood production. What steams my clams is that at the same time, they won't allow our rice to be imported over there because they want to support their own agricultural economy. Our rice is a lot better than theirs, but they outlaw it. That's why when you go to the airport, all the Japanese tourists are carrying on the minimum two pound/one kilo boxes of rice from the supermarkets here. That's all they can bring in and it's like caviar over there. Maybe we ought to raise the price of our prime lumber accordingly so that it is cheaper for us and more expensive for them!

[Bob Smalser]

Originally posted by Canoeyawl:
I like Sitka spruce; the engineering numbers indicate that for a given weight Select spruce should be stiffer than Douglas fir and weight aloft is everything.
A common myth. Look at your numbers again.

DF is around 24% stiffer and is 20% stronger than spruce when a spar is bent to the the breaking point.

It's also 20% heavier.

You can reduce the diameter of a DF spar to the point where it's just as strong as spruce and no more heavy.

Here's my local recommendations for boat-grade wood. No doubt in my mind Ross'll benefit from shopping around:

Queen Charlotte Island Boat Lumber
PO Box 293
Port Clements BC V0T 1R0
250-557-4282
obrien@qcislands.net

McClananhan Lumber, Inc. Larry McClananhan
P.O. Box 1483, Forks, WA 98331
Phone: (360) 374-5887 Fax: (360) 374-5800

Pacific Western Timbers
8000 Imperial Way, Port Orchard, WA
360-674-2700

Moreover, Ross....you don't really need the 8 dollar per bf, 12 rings per inch old-growth fir. As long as you use clear, straight-grained heartwood, the 4 rings per inch tree farm fir wil work just dandy.....all those strength figures I quote are for plantation DF. You can buy such stock around your neck of the woods for a fraction of the prices you quote.

[ 11-11-2005, 12:14 AM: Message edited by: Bob Smalser ]

[Bob Smalser]

Originally posted by Bob Cleek:
Sitka spruce has the greatest COMPRESSION strength of anything around and that is what you want in a lightweight spar. More myth.

While nobody has to tell me these engineering numbers and the real world have differences, the compression perpendicular to grain value for Sitka is 580psi and for DF it's 800psi.

That's a huge difference not in spruce's favor. Only in shear are they about equal and a spar only experiences minor shear...the propensity of the wood to split like firewood...at the partners. It's MOE...how much pressure it takes to bend it.... and MOR....how much pressure it takes to bend it to the point of breaking... that are most important.

[ 11-11-2005, 12:33 AM: Message edited by: Bob Smalser ]

[Bruce Hooke]

Originally posted by BirchBark:
So what would be a good choice for wood on the East coast? Baltimore area.
It would need to be something in stock as it would be for a small boat and not alot of BF.
Anyone have any good boat lumber yards I could go to?

Thanks,
ChrisFor a really small boat just go to the lumberyard and find the clearest SPF studs you can and mill them into mast stock. For more details you may want to start a new thread. This issue has come up before too, so a look through old threads should turn up some good information.

[StevenBauer]

Here in Maine I can buy air dried eastern spruce "staging planks" at any lumberyard. I used the quotes since OSHA won't let them call them staging planks anymore. But they still sell them. 2" thick and 10" wide by 16' long and they cost about $25. I've had to go through the pile to find ones that were perfect - straight grain, clear, no knots - but they're in there. Go to your local lumberyard, not the big box store, and ask around.

Steven

[Bruce Hooke]

Sadly, the so called staging planks at my local lumberyard have so many knots that they would be useless as mast stock, but that is certainly an idea worth checking in other places...

[Columbia 112]

OK I’ve been looking thru the books and LFH recommended “any of the spruces or rift-grain firs of fine texture would be good” and I can’t find any specific reference in the “How to Build Rozinante” article or on the drawings, so the Holy Sitka sounds like a bit of a 50/50 draw, you either use it or you don’t. I agree that sometimes you get dazed by the numbers and their diminishing returns. Wow! 16 rings per inch! Does it really matter? Probably not in the average boat mast. So, if I can find a good old lumber yard, get the “Old man” to show me what real fir looks like, hand pick it if they’ll let me, then scarf and Weldwood plastic resin glue to my hearts content, I think all will be forgiven by the Sitka Gods.

Ross

[Canoeyawl]

A spar is a loaded column also subjected to bending stresses. There are some calculations involved in the design and I would not want to suggest that one could reduce any dimensions and maintain strength. Part of the strength calculation involves the diameter of the column and that strength is a function of the diameter squared. It’s that “squared” thing that does it…
Spruce will be a stiffer spar for a given weight, not size.

[werner]

interesting ....if the choice between spruce or douglas isn't critical and growth rings of 5mm ( 5 an inch) are nothing to wory about does that mean I can go to the lumber yard around the corner and get some 6 meter beams with straight grain to build a (safe) mast as strong and almost as light as a (sitka)spruce mast even one of 45 foot???
javascript:void(0)
Confused
Always asumed from what i have read that you had to use old growth.
or is there some limit to the specific weight to watch out for?
This would be good news since it is almost impossible to find (sitka)spruce here,but(fast grown) douglas is no problem.
regards
werner :confused: :confused:

[merlinron]

werner, i think what's being said here is that in reality, the old growth stuff is the best if yur looking for the ultimate strenght to weight, but not absolutely necessary. if you are carefull in your inspection and choose only the best your local yard has to offer, it will work fine and save you a bunch of money.leave the old growth stuff for the really heavily stressed big masts, the smaller average mast will do just fine with carefully selected newer woods.

[Dan McCosh]

The compression load in a mast is parallel to the grain, not perpendicular. Don't have the numbers, but I doubt that the Sitka is weaker than the fir in this dimension. Also--making the mast smaller in diameter to save weight would have a disproportionate effect on stiffness. I would think fir would make a reasonable mast, but last time I looked, the cost was about the same as Sitka--comparing good clear stock for both woods.

[George Roberts]

Columbia 112 ---

The nice thing about old boats and old boat builders is that little enginering was done. What was done was not all that precise.

I expect that either Sitka Spruce or Douglas Fir will serve you equally well.

[Bob Smalser]

Originally posted by Columbia 112:
...sometimes you get dazed by the numbers and their diminishing returns. Wow! 16 rings per inch! Does it really matter? ....then scarf and Weldwood plastic resin glue to my hearts content... I'm not suggesting that anybody make major scantling changes without having the engineering done....and I'll defer to several of the posters on most matters involving sailboats. I'm just a wood tech who doesn't buy into all this mythology about spruce...if fir's 24% stiffer yet only 20% heavier, it's impossible for spruce to be stiffer per unit of weight, regardless of cross section.

In itty-bitty scantlings like airplanes use, there is a practical limit on how small you can go and still achieve good joinery, and spruce engineered out the best. Spars don't have the same issues....especially with modern glues....and on the West Coast, spruce is a wood of the past. All those Canadian old-growth harvests where the spar grade spruce comes from are being replanted in DF...every single one of them.

Accordingly, I strongly suspect the great designers of the past faced with today's situation of increasingly-precious Sitka versus ubiquitous and relatively inexpensive DF of the same quality, would have specified DF.

http://pic3.picturetrail.com/VOL12/1104763/3019409/36929015.jpg

http://pic3.picturetrail.com/VOL12/1104763/3223936/39972445.jpg

Much as I love tight, old-growth fir like in the top pic, all the engineering numbers I quote are done on the second-growth stock in the lower pic. Comparing the two is like comparing 5-lam plywood to 9-lam....with more layers and more resin/glue, it's a bit stronger and more durable, but nothing to get too excited about. It's also heavier. That top pic, BTW, is part of a 18k BF load of B.C. stock bought 5 years ago for $1.80/BF...including the tariff.

And although I've probably used well over a 55 gallon drum of urea resin glue in my lifetime, I strongly recommend marine epoxy for your spars. More flexible and more forgiving. You need close to 70 degrees to get a good cure on resin glue, and on assemblies that large, I can only achieve that a couple months out of the year around here.

[ 11-11-2005, 12:42 PM: Message edited by: Bob Smalser ]

[Bob Smalser]

Originally posted by Dan McCosh:
The compression load in a mast is parallel to the grain, not perpendicular. Don't have the numbers, but I doubt that the Sitka is weaker than the fir in this dimension.DF is 28% stronger than Sitka in compression parallel to grain. 7230 to 5610 psi.

[Bob Smalser]

[ 11-11-2005, 10:40 AM: Message edited by: Bob Smalser ]

[Don Kurylko]

Bob is absolutely right. Either Fir or Spruce will get the job done and get it done well. The biggest issue is weight. If the boat you are building can tolerate the extra weight, then it’s a no brainer - Fir is the answer. If on the other hand, the boat you are building is tender, then obviously Spruce is the better choice (and money isn’t the issue). However, at $12 a bd. ft. for Spruce, perhaps Carbon Fibre might even be a better choice. It can be had these days in mock Spruce colours and it would be far stronger and stiffer than wood. It all depends on what you are trying to achieve. Many of the big “Classics” that have been restored over in Europe sport just such carbon fibre spars, even the gaffers. It makes sense, if you’ve got the cash.

[Dan McCosh]

Given the numbers, I'd say the stiffness to weight ratio of the two should be about the same. The price here, however, ranges from $6-$10 for AA aircraft Sitka, and about $5 for fir. For 2x6 sections, its $6 for the Sitka. The difference for most masts would only be $1.

[Nicholas Carey]

Originally posted by Don Kurylko:
Bob is absolutely right. Either Fir or Spruce will get the job done and get it done well. The biggest issue is weight. If the boat you are building can tolerate the extra weight, then it’s a no brainer - Fir is the answer. If on the other hand, the boat you are building is tender, then obviously Spruce is the better choice (and money isn’t the issue).Only for solid spars.

Fir is both stiffer and stronger than spruce: consequently a hollow spar in fir of a given length, diameter, strength and stiffness will weigh in about the same in either fir or spruce.

That's because the wall thickness of the fir spar can be reduced due to fir's additional strength/stiffness.

Let's look at a 15 meter x 15 centimeter round spar (49.2 x 5.9 inches) as an example. For the sake of simple calculation, we'll make our spar an untapered ordinary cylinder.

Using the FPL's Wood Handbook as a reference, I figure our example spar as follows:

Solid Construction. In solid construction, the volume of the wood in the spar is 265,071.88 cm^3.

In Douglas Fir (s.g. 0.48 @ 12% moisture content), that works out to 142.6kg. In Sitka Spruce (s.g. 0.36 @ 12% moisture content) that works out to 106.8 kg. Clearly Sitka is the big winner, 25% lighter than the fir spar.

Hollow Construction. According to Skene's/Nat Herreshoff's scantling rules, the normal scantling for a hollow spruce spar is that the wall thickness should be 20% of the major diameter of the spar.

In Sitka Spruce, the volume of the wood in our hollow spar at 20% wall thickness works out to be 95,425.83 cm^3, or 38.4 kg in weight.

However, since we know that Douglas fir is both stiffer (35%) and stronger (40%) than Sitka Spruce, we can reduce the scantling of the spar.

Reducing the scantling by 25% from a 20% wall thickness to a 15% wall thickness while still keeping the 15cm diameter, the volume of the wood in the Douglas Fir hollow spar is reduced to 73,557.45 cm^3, or 39.6 kg in weight, still yielding a spar that's as stiff and as strong (and arguably stiffer and stronger) as our sitka spruce hollow spar.

That's a difference of just 1.2 kg (2.6 pounds) distributed over 15m (49.2 feet.)

[Columbia 112]

Maybe a composite spar isn’t to far off the mark. Good resin and glass can be made for about 3$ a pound. If I made the spar weigh the same in glass as in wood it’s got to be strong enough. I estimate that the two masts and booms will use 140 pounds of wood that’s 420$ worth of composite. I could make a foam mandrel, wrap it in glass, bag it and infuse the resin. Is this too radical or blasphemous? Just trying to think outside the box.

Ross

[emichaels]

Ok. Its clear there are some pretty smart people commenting on this thread. But..........No body is talking about what makes a beam, after all thats what a spar is, fail. Beams always fail in tension. Not compression. Compression by definition is resistance to tension. And vicey versa. Differnt woods based on their respective cell properties will have different relationships between tension and compression.. To argue only one side of this equation will, in this case DF vs SS, prove errant. Sitka spruce at 370 psi (tension failure) is actually stronger than DF at 340 psi. Remember tension is the ability to resist compression, in a beam. In a hollow beam it is most true as there is an remote axis to divide the tension and compression side of the equation. If one produces a vector diagram of the loads on a verticle spar of DF and SS with the same scantlings the SS will be stronger. Stiffness notwithstanding. A little flex is okay, right.. You just don't want a two pc spar out on the water. Sitka is the engineering answer. Now what looks better................

BTW My numbers are form Hoadleys "Understanding Wood'. For those that don't have this book. It is the most important book a person working with wood can have. Without question.. I bet Bruce has a copy.... ;)

Eric

[ 11-11-2005, 09:02 PM: Message edited by: emichaels ]

[Bob Smalser]

Originally posted by emichaels:
Beams always fail in tension. Not compression. Compression by definition is resistance to tension. Hoadley, 1980, page 122, 128, 135.

I've always considered Modulus of Rupture...bending a stick of wood till it breaks...which already fully accommodates the beam tension and compression factors you mention, a more accurate picture of the stresses on a spar.

DF is 20% stronger in MOR than SS.

[ 11-11-2005, 09:36 PM: Message edited by: Bob Smalser ]

[emichaels]

I understand where you are coming from there Bob. As you will see on PP 111 the MR is under the "Static Bending" column. That would apply to a beam that is under load over a long time. As discussed on pp 128 (1980). We talking about a verticle spar experienceing and resisiting dynamic loads. Which require a dynamic value to resist, ie tension values.

[ 11-11-2005, 09:39 PM: Message edited by: emichaels ]

[Bob Smalser]

Except there's only one MOR.

No MOR (static) and MOR (dynamic).

There would be if there were tension issues between the two. In general, the faster you apply the load, the better the wood resists it. MOR (static) would be a weaker value than MOR (dymanic).

[ 11-11-2005, 10:20 PM: Message edited by: Bob Smalser ]

[seo]

My old H-28 had a Sitka main and a Doug mizzen (built like that in 1945. Go figure.) Neither one broke.
I think in "Common Sense of Yacht Design" LF Herreshoff comments that Sitka is particularly well suited for use in solid masts with looped shrouds. Like the ones his father built.
According to Phil bolger, LFH was the first person to use mast tangs the way we all use them now.
For that sort of design, the local strength of the wood (ability to hold screws) becomes important. Its tendency to check or twist becomes less important. For myself, there's no wood that glues more predicatably than Dougfir. These values may be more critical than stiffness, tensile strength, etc.
The very best sitka goes for making musical instruments. Soundboards of Yamaha guitars, for example. The nicest sitka I've ever seen was used for the main wing spars of Bellanca Viking aircraft.
Another nice thing about Doug is that it's more resistant to denting. If you build your Rozinante with the authentic halyards with runner blocks going aloft, you'll spend a lot of time dealing with dented spruce and chipped varnish. For that reason consider sheathing the leading edge of your spreaders with something very hard (brass sheet maybe?)
A big commercial lumber yard might have some long Dougfir planks around. Used to be called #1 structural, or something like that. It was used for long rafters/joists in commercial construction. In Minnesota I used (1970's) to build trusses for pole barns with it. 2X12X24' planks, clear and straight-grained.
As far as using Yellow Pine for masts go, I wonder about that. It's awfully heavy. As I understood it, 1) the king of E. sent foresters around colonial New England hewing "broad arrow" marks into trees that were reserved for Royal Navy masts. And 2) once again according to LFH, masts in ships of that era were actually built up, and sheathed over. Never having seen HMS Victory I dunno.
Masts of smaller vessels were made out of solid single timbers. The Maine schooners all (as far as I know) have Dougfir masts.
seo

[Canoeyawl]

Spars/Masts are more complex than beams. They are eccentrically loaded tapered (often hollow) columns subjected to a variety of bending and buckling forces both static and dynamic. There are included fastenings, and attachments.
It is a lot of work to properly design and engineer a mast. If the engineer (L.F. Herreshoff in this case) says Fir or Spruce will work to his drawings, Spruce will be lighter - and more expensive LOL.

[islandteak]

Try TF specialty sawmill in Courtenay and Timberwright in Campbell River.
...Ken

[emichaels]

Originally posted by Canoeyawl:
Spars/Masts are more complex than beams. They are eccentrically loaded tapered (often hollow) columns subjected to a variety of bending and buckling forces both static and dynamic. There are included fastenings, and attachments.
It is a lot of work to properly design and engineer a mast. If the engineer (L.F. Herreshoff in this case) says Fir or Spruce will work to his drawings, Spruce will be lighter - and more expensive LOL.Actually, a spar is not a very complicated beam a force diagram can be drawn for it and moments calculated for it. because it tapers is not an element that makes it complicated. Also a hollow beam is much easier to 'know' how it will react under stress because, as I mentioned above, the tension and compression are seperated by air, ie, they are isolated and can be considered seperately.

[emichaels]

Originally posted by Bob Smalser:
Except there's only one MOR.

No MOR (static) and MOR (dynamic).

There would be if there were tension issues between the two. In general, the faster you apply the load, the better the wood resists it. MOR (static) would be a weaker value than MOR (dymanic).MOR and MR are the same thing. In engineering it is refered to as MR (modulus of rupture). The 'moment' represented by a value at rupture is a static number, representing point of failure. Tension is a dynamic value that can be measure from 0 up to the point of rupture when tension fails. Tension is the value that we are concerned with as a spar is only load to MR when it fails.

[ 11-11-2005, 10:46 PM: Message edited by: emichaels ]

[Canoeyawl]

I think it’s a BIG deal to figure these spar loadings. Just to figure the what the compression loading from the jib alone on this mainmast in question would be at say - close hauled, 20 kts breeze, no heel and a good chop throwing green water up the bottom five feet of the sail on a cool day??? Then add details like, deck stepped? Keel stepped? How to make the forestay attachment? It goes on for a while… Then, if you got it wrong someone could perish….Masts are a big deal. It frightens me.

[emichaels]

Originally posted by Canoeyawl:
I think it’s a BIG deal to figure these spar loadings. Just to figure the what the compression loading from the jib alone on this mainmast in question would be at say - close hauled, 20 kts breeze, no heel and a good chop throwing green water up the bottom five feet of the sail on a cool day??? Then add details like, deck stepped? Keel stepped? How to make the forestay attachment? It goes on for a while… Then, if you got it wrong someone could perish….Masts are a big deal. It frightens me.I don't think I said it wasn't a big deal. If you want to get home under sail its a really big deal. I just mean it is not as complicated a beam as say an airfoil like a wing on a jet. A bridge is one of the more complicated beam calcs out there. I didn't mean to imply that a mast or spar was inconsequential, it just is not that complicated mathematically.

[ 11-11-2005, 11:25 PM: Message edited by: emichaels ]

[Columbia 112]

Ken

Timberwright have quoted 13$ BF for Sitka.

Ross