Mastly Musings

[Tim Diebert]

....Mostly Mastly Musings

I was sure someone here was having a chat about masts, weight and construction methods recently. ? Maybe I read it somewhere else...perhaps over on the B&B board. Anyway, for what it's worth....(Ray, you can add this to your vast treasure trove of Numbers, calculations, weights, measures and methods)

I am replacing all my standing rig this spring. New mast, boom, gaff and bow sprit. Not to mention hatches, companionway, dagger board and trunk.

To me it looks like I am going to spend the summer doing even more dreaded woodworking rather than sailing....bugger.

All spars are bookmatched super straight grain air dried local Spruce. Awesome material. Super light, very strong and gorgeous. I made a set of 8 foot sweeps about 15 years ago out of the same stuff....I am going to be buried with these rascals....they age so wonderfully....sooooo light and strong.

I am right in the heart of wood world and picked through about 600 BF of a Buddy's best material to get this stuff...and paid a whopping $1 per BF canucklian. Am I lucky or what?

Anyway, I altered the masts dimensions quite a bit. The stock scantlings are ridiculously huge so I am smaller around and a tad longer. I want to fly a pendant of some sort with the 9" extension. A jolly roger would be appropriate...or the family crest (which would need designing).....

Anyway (I been saying that a lot...) the stick is almost round right now, and about 16 feet long...and it weight in at 13 1/2 lbs....and a hell of a lot easier and quicker to make than a birds mouth version, though admittedly not as strong. Though IMHO, a mast for one of these boats does not need to be that strong....

Onward and Upward

[Tim Diebert]

My guess is the mast can be much thinner then plan recommendations call for. How much thinner, Tim may find out.

So Tim, How thin are you going to come up with 13 1/2 lbs? Is this entire weight of mast from hull floor to tip?

>Yes, the entire mast..tapered...from end to end. Basically it is working out to about 2 7/8" at the foot and 2 1/2" or so at the head. It has a pleasing line to it so far. It is a little scarry how light it is...but I am always amazed at how strong this material is. Plus it sounds good...I use it to make guitars all the time :roll:

I have to get a bathroom scale out to the boat and measure weight of the tapered mast from tabernacle to tip for my own curiosity.

>I have my old mast in the shop and I will weight it later...good idea. It might be interesting to compare. I can tell you right now the difference is great. I always thought my previous mast was much too heavy and large for such a light small boat. As you say, I guess we will find out.

I think the thread you were thinking about was on the BYYB site.

>Could be....though I can't recall being over there is a very long time....I will go check it out.

My guess is that a birdsmoth mast will weigh a bit lkess then juust a tapered mast but probably not that much. maybe 10-20% at most. Now if mast was un tapered, the weight savings of a hollow vs solid would be much greater, up to a third.

>I am sure you are right. The birdsmouth would take a lot of abuse as well.

My plan was to try and reduce as much weight up high as possible. I never had any trouble setting up the old mast...but the new one is going to be a breeze.

I had also originally intended to change the sail shape a bit as well....to more of a higher peeked Gunter...but bailed on that and decided to go with a Lapper sized headsail. I am trying to improve windward performance. A navel architect I spoke to said a better headsail would give me more advantage than the new main shape. Besides, it will be much quicker for me to get all the new work done and get sailing if I stick to the original numbers for the standing and running rig.

Speaking of sails, I bought a kit from Dave at Poly sails. I will just be making my main from the kit as I have an old Dacron headsail a friend donated that I will be cutting down to make a headsail. The kit looks great so far. All super materials. Fast delivery.

[Bill]

They had quite a mast discussion over on the WB site sometime within the past 4-5 weeks. A guy was putting in a solid Oak one and of course everyone was trying to talk him out of it (small boat too). There was a few calculations and wood types thrown into the usual mix of conversation(s)...

Bill

[Tim Diebert]

As it turns out, my new mast is 2 13/16" tapered to 2".... basically. As I said before, about 13 1/2 lbs.

My old mast made of fir and hemlock is 3 1/8th" at the foot and 2 1/4" at the head and it looks like the previous owner/builder did a four piece box style section. Anyway, the old mast weights in at 28 lbs.

That makes for a 14 1/2 lb difference. It will be interesting to see what kind of difference in effect, balance or performance there might be.

I have been looking at similar sized boats to the Weekender and found that their masts were quite a bit smaller....so I thought it might be a good thing.

My gaff and boom will also be made of this light weight Spruce. I should notice quite a difference with weight aloft. Being as the old gaff was red oak.

With the right grip...this thing could make a great jousting lance

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[Charlie Jones]

The lighter gaff would be a good thing, but I'd keep the older heavier boom. On a gaffer the weight of the boom goes a long way to aiding sail shape, since there is no real vanging. The boom weight works as a vang after a fashion.

Good luck with your mast - I hope it isn't TOO light and thin

[Tim Diebert]

I haven't cut it up yet Ray....though I am quite sure it is hollow with plugs at either end. All 3/4" material. Like a brick this thing is. It was nailed (and hopefully glued) together with stock lumberyard lumber. There is likely a pound or two of filler alone :shock:

Thanks Charlie...right, my thoughts as well. I have spent my entire life being contrary...so might as well keep on keeping on. Mr. Guinea Pig.

As for the boom, there is zero chance this thing will be anything but nice dry kindling for the shop stove. The new boom is lighter (just working on it right now...) by about 2 lbs as far as I can see right now. I am sure it will be fine....though if there is any noticeable change from my previous sail shape I will be sure to whine regularly and with enthusiasm. Thanks for the advice.

[Knut]

Hi,

I brought up the question about light weight masts for Weekenders earlier this year, asking if anyone has direct first hand experience from using the standard mast and later a light weight mast. Nobody seem to have done both on their own boat?

My point is that the standard mast is extremely heavy and strong, compared to what it need to be (all in relation to the boat size and sail area). It is also a point that the Weekender has no weighted keel, so the maximum force from any wind and sail combination is quite limited. If this limit is exceeded the boat will be knocked down; as simple as that. Over-dimensioning the mast is not bringing anything.

Because of the flat bottom, the heel angle is seldom more than 15 degrees (and anything more does not pay off in speed anyway) and within this angle of heel, the gravity point of the mast will not be far outside of the boat centerline (small momentum). However, as soon as there is a gust or any other cause of further heel, then the weight of the mast starts counting increasingly much and can become the difference between staying in control and a swamping of the boat. Certainly, in generally strong wind the performance also has to be better with a light weight mast.

I am going to build a new mast, using the following basic method:

Cut the existing solid mast 4" below the lowest bolt in the mast head and 4" above the tabernackle hinge.

This piece I will replace by exactly the same length and dimensions (tapered and with rounded corners) using polystyren foam covered by carbon fibre set in epoxy. In the center I will put a piece of 3/4 x 3/4" wood for taking axial compressive load. My mast is painted, so after smoothening and painting of the new piece, there will be no visual difference between my standard mast and the light weight one.

As soon as I get a chance to work on this it will be done. Based on the test-piece I made before using mailing tubes and PU-foam, it looks like I may be able to save 15 lbs of weight compared to the current version.

I am convinced it will make quite a difference and I will be much more comfortable in a gusty wind situation. Reports and facts to follow later

[MikeStevenson]

Is anyone doing anything to preserve the Sitka Spruce (and other good types of Spruce) forests? I know that they were Strategic Resources during WWII, but since the military went all metal or composite, I don't think anyone cares militarily. I know that the Rayon fabric producers were shredding Spruce trees to make ugly shirts during the fifties and sixties; I don't know if this is still happening. It would be too bad to lose the best wood to idiotic wastes.

Mike

[Guest Anonymous]

....Mostly Mastly Musings

All spars are bookmatched super straight grain air dried local Spruce. Awesome material. Super light' date=' very strong and gorgeous..............I am right in the heart of wood world and picked through about 600 BF of a Buddy's best material to get this stuff...and paid a whopping $1 per BF canucklian. Am I lucky or what?

Anyway (I been saying that a lot...) the stick is almost round right now, and about 16 feet long...and it weight in at 13 1/2 lbsOnward and Upward[/quote']

Tim, was this wood stored outside under cover, in an outside unheated building, or inside a heated structure?

[Tim Diebert]

....you lost your cookies? Flu? Too much partyin Prof?

That particular stuff was rough sawn, stickered outdoors, planed and brought indoors, stickered (dry piled with strips) again and left to dry in a very large heated shop...with circulated air...fans etc. It is quite dry.

This guy I get it from has a sash and door shop. He buys lifts of what he hopes is Larch and Fir. He allows me to high grade it for whatever I need. He has no idea that this "really weird light stuff' is Spruce.

Even here in the middle of softwood nirvana, they don't grade out most species. Quite of then the grade will be Larch Fir Hemlock. Whoever buys the stuff has to be willing to get a little of each. Spruce grows sporatically throught larger commercial stands of Fir and whatever. They just take and process it all. I believe, that for some of the high end market (Japanese standards) they will pull and grade for the very best stuff. I am not sure though.

As for Mikes question above Cookie Mans....around here Spruce is kind of like a weed. Nobody harvests it on a strickly Spruce basis...that I know of. The only heavy use of the very best Spruce would be for sound board (acoustic guitar) wood. Most of that grows on the west coast anywhere from vancouver to Alaska. That is the only product from Spruce that gets a good price. Otherwise, the stuff is all over the place. It's not great for framing, or furniture or posts (the decay resistance is lousy) and it is crappy firewood....so there always seems to be lots of it. I have three really big trees in my yard. Spruce is super for airplane parts, musical instruments and oars/spars. I love the stuff. Ever hear of the Spruce Goose?

I was once involved in making a few parts for a light experimental aircraft. It was a beautiful thing. The part I remember the most was this amazing plywood the owner supplied me with for making some gussets and small bulkheads. 1/8 Spruce plywood. There might have been 8 or more lamination in that 1/8". Just gorgious stuff...so strong and light. I have never seen or heard of the stuff since...though I am sure it exists somewhere.

What a rant for such a simple question....Ray lost his cookies and I have diarea of the finger tips. We are in sad shape.

Tally Ho

[Tim Diebert]

Oh and Ray......if you don't already know everything there is to know about drying wood, and I am sure you do :wink: ......it is something I have done a lot of in the last 25 years and if you need any guidance in this area....after you stop blowing chunks of course....fire away.

[Tim Diebert]

OK OK....no, I don't use one. Never have.

BECAUSE...I always let every piece of guitar wood get to EMC before using it to make an instrument. My shop is climate controled and remains within a certain tolerance year round.

The Spruce for the mast is emc for our area(not my shop)...which is quite dry. Hard to say what moisture content it actually is.

Ray, there are just some times when your books, calculators and fancy cypherin just don't add up......I got me a 13 1/2 lb mast. The good stuff.

It remains to be seen whether this tiny light little Spruce noodle makes for a dandy mast for the mighty Tugboat Annie.

[Tim Diebert]

Hahahahahahahah....you AMAZE me Bro!

I got this image in my mind of you.......Beaker.

What a guy.....that's great. I just got back from the pub and read this....I'll be chucklin till morning. Thanks Professor Raymond.

...you kill me man.

[Tim Diebert]

Oh, by the by. I also have a copy of Hoadly's book....must be 20 years old. I don't actually read it. It's just to impress the chicks...hick....time for bed.

[Tim Diebert]

I just hope your voice is nothing like Beakers....

[Tim Diebert]

...ya but, you're still skinny!

[Johannah]

Cultural reference for the hopelessly unhip, please? :roll:

[Tim Diebert]

As far as I know there is nothing cultural going on here Jo.

Beaker was a Jim Henson Muppet.

Just watch....the skinny part will show itself....once Ray gets his slow chubby butt in gear.

Unhip? You are kidding right?

I can't think of more hipper young lass then yourself!

8)

[capt jake]

Well, Ray, I certainly like the new 'you'! LOL :D I like that Avatar!!! :D

[Tim Diebert]

It would have an expected weight of 13.5 lbs in spruce.

...but of COURSE you would have expected that Beak...it said so in the book.

Your a good lad to know.

Yes Jake, Ray's new avatar is just the ticket. It suits him...a Chubby Beaker.