A wood mast for the CS20

[lncc63]

Reading about the CS20, I was immediately attracted to it. I thought to myself "this would be a great excursion boat" but with a little bit of hindsight from the my first boat I decided to read up as much as I could. By the way, this is a great little community you guys have here.

Well based on what I've read, I found I'd have a problem with the masts which, correct me if I am wrong, need a 3" aluminum pipe. I live in the Philippines and as far as I and our small group of boatbuilders can determine no such pipe can be sourced locally.

Still I had my brother buy the plans. It is such a nice boat.

My question is can someone tell me how an aluminum mast is? How much does it bend? I read the bending behavior is important. Any ideas how to get the equivalent characteristics in wood maybe laminated with epoxy? I don't mind the solution being a lot of work.

Thanks in advance.

[ChrisObee]

Do a search for Birdsmouth mast....

[Frank Hagan]

Reading about the CS20' date=' I was immediately attracted to it. I thought to myself "this would be a great excursion boat" but with a little bit of hindsight from the my first boat I decided to read up as much as I could. By the way, this is a great little community you guys have here.

Well based on what I've read, I found I'd have a problem with the masts which, correct me if I am wrong, need a 3" aluminum pipe. I live in the Philippines and as far as I and our small group of boatbuilders can determine no such pipe can be sourced locally.

Still I had my brother buy the plans. It is such a nice boat.

My question is can someone tell me how an aluminum mast is? How much does it bend? I read the bending behavior is important. Any ideas how to get the equivalent characteristics in wood maybe laminated with epoxy? I don't mind the solution being a lot of work.

Thanks in advance.[/quote']

Graham may know of a source for aluminum in your part of the world. He'll chime in here when he gets a chance.

I think the problem with wood might be that wood is quite a bit weaker than aluminum for the same diameter and especially weight.

[lncc63]

Do a search for Birdsmouth mast....

Hi. Actually' date=' I'm building a "birdsmouth" for the boat I am presently working on. This is a prototype:

[img']http://i57.photobucket.com/albums/g227/lcasambre/IMGA2066.jpg[/img]

Yes, as Frank said, it does weigh quite a lot more, in this case, twice the equivalent in aluminum. I wouldn't really mind the boat going a little bit slower because of the weight but speed I suspect is not all there is to it.

[Designer]

There is no reason why you can't use wood masts. They will come out heavier than aluminum but you have to make do with what you have. Sailing wise you will hardly be able to tell the difference. Stepping and unstepping the mast will be a bit harder and if you happen to capsize then it will take a bit more force to right the boat.

The specs should be on the plan for wood masts. While in Papua New Guinea I used a wood called klinkii pine for spars with very good results. As many of your trees are related to PNG trees I suspect you will have a similar wood. Sitka spruce is the gold standard for wood spars over here but not many of us are willing to part with that much of our treasury for it and substitute douglas fir or eastern white spruce.

The main advantage of using aluminum is as Ray said, they are already made and are a known quantity.

[Charlie Jones]

One point about using wood masts rather than aluminum.

We used lower half aluminum and upper half birds mouth on the Princess 22 I built. And slightly heavier tubes for the aluminum, since the correct size didn't seem to be available.

The masts are slightly stiffer than they would be with all aluminum and correct tubing specs, so the sails, which were ordered through Graham and obviously designed and cut with the bending charactersitics of the aluminum masts in mind, have slightly too much luff round in them for the stiffer masts.

WHEW- talk about a run on sentence!!!!

So if you DO choose wood, or otherwise change the stiffness of the masts, let your sailmaker know so he can compensate.

[lncc63]

Thank you for all the input. It maybe a few months before I can start but this is one of these that just has to be built.

[Ken Haydu]

Louis

I would think that the right size piece of bamboo would make a fine mast. It is certainly a strong plant, has a natural taper to it, and is flexible. Would take a minimum of work to fashion the masts from bamboo also

[JeffM]

Would heavy wooden masts affect the boat's stability? A few pounds on deck may not seem like much, but those masts are very long lever arms. By the way, that's a pretty mast section you have there! I gather the teardrop cross-section is mean to be aerodynamic when sailing to weather. I'm curious about the section of pipe or tubing in the aft part--what is it for?

[lncc63]

Ray is right Jeff. It is for a bolt rope.

Yes bamboo is pretty strong and is a neat material to use. However, I'm very much a novice to all of this so I won't know if it is appropriate or not for the CS20. I'd also be interested about what the experts have to say. For sure, bamboo is used as masts on some of the local boats.

BTW, sorry I could not answer immediately. I live in a far away timezone so I only normally see and can respond to posts after an 8 hour lag.

[Peter HK]

Hi Louis

Don't apologise for any time zone issue- it is the internet and therefore global. Remember that everyone else is in the wrong time zone and therefore their replies are tardy

I also am having trouble with availability of the appropriate aluminium tubes (here in Australia) so I may have to go to birdsmouth masts. I think I will make them a little undersized (the CS17 plans call for 5/8 inch thick staves but here with metric I can get 12 mm or 19 mm, so 12 mm seems the go) and put a layer of carbon on the outside. Maybe you can get carbon fibre also- it would make them a little lighter. I covered the mainmast of my Bolger 30 ft folding schooner with carbon and it certainly made a big difference.

Here is a link to the folding schooner for anyone's interest.http://sports.webshots.com/album/548246269VtgyuF

I ordered the ply/timber /epoxy yesterday so hope to start next week.

Peter HK

[mustangermatt]

About weight aloft.

I was concerned about this because I built oversize solid spruce masts for my 17. I think they came out to about 20-25 lbs apiece. Turns out the only time I notice the weight is when I step them.

They are also very stiff. Probably not as forgiving to puffs as the more flexible masts, but again the boat has never capsized so I guess it works out ok.

[JeffM]

Peter, your folding schooner looks like a whale of a lot of fun! I like her name, too. Am I right that you have sleeve luff sails raised by halyards?

[Peter HK]

Am I right that you have sleeve luff sails raised by halyards?

Yes Jeff,

They are based on the Wharram Tiki style luff pockets- they unzip to take off and are large for 2 reasons. Firstly it means they can crush down easily for dropping/reefing and secondly they may have an aerodynamic benefit a little like a wing mast- this seems to make a difference on a broad reach where flow stays attached to the sail very well.

As to fun, there's plenty of that. The fastest GPS documented speed has been 13.9 knots, but when it's really moving there seems too much spray/action/fear to look at the GPS. The only problem is finding crew- she goes best with 5 but you should have seen the time we had 3 onboard in a gale with one on trapeze

My ply etc arrived this afternoon so I can start on my CS17 this weekend.

Peter HK

[Peter HK]

Am I right that you have sleeve luff sails raised by halyards?

Yes Jeff,

They are based on the Wharram Tiki style luff pockets- they unzip to take off and are large for 2 reasons. Firstly it means they can crush down easily for dropping/reefing and secondly they may have an aerodynamic benefit a little like a wing mast- this seems to make a difference on a broad reach where flow stays attached to the sail very well.

As to fun, there's plenty of that. The fastest GPS documented speed has been 13.9 knots, but when it's really moving there seems too much spray/action/fear to look at the GPS. The only problem is finding crew- she goes best with 5 but you should have seen the time we had 3 onboard in a gale with one on trapeze

My ply etc arrived this afternoon so I can start on my CS17 this weekend.

Peter HK

[jaxsailr]

Wow that looks like a lot of fun....

Will you use the Wharam luff sleeve on the Core Sound?

Niels

[Peter HK]

Niels

I will be using standard slides and track on the Coresound as the sprit boom makes reefing more difficult with a luff pocket. I'll use slab reefing as it works somewhat better than trying to reef around the mast. As I intend to single hand quite often I want the very reefed sail shape as good as possible.

By the way- with reference to the original post- I did manage to get aluminium for the masts but had to order it from online metals in the US. Came in under a week but the postage wasn't cheap :shock:

Peter HK