Mast Materials

[Maria CS20 104]

I am looking at mast materials and availability here in north louisiana. Looking at spruce, very hard to find and I am interested in wether or not cyprus would be an appropriate material. I can get fir but in short lengths that would require it to be overlapped and I am not sure how much of an over llap I should use. I am planning solid masts, not worried about speed but I think solid mast would be fine and substantial enough for the beast. I will round the bottom three feet and plan to stick with a rounded square mast to the top. Any IDEAS are appreciated and input welcome. Aluminum is out of site on cost and I am ready to finish and get her wet.

Jim A

[hokeyhydro]

I used cypress for a 21' mast on a catamaran. Built the mast hollow using the birdsmouth method. 8 staves 7mm X 14mm. My birdsmouth mast had several scarfs (splices) since boards were only 16' long. 8:1 scarf ratio is fine, and I staggered the joints so no two joints among the 8 staves lined up.

I think a solid mast on a CS-20 would be far too heavy. Especially in doug fir. Even in spruce or lighter but expensive sitka spruce I think a solid mast would be a tonner. If you have a table saw or router you do a birdsmouth build.

[makenmend]

Also made my small trimaran mast using the birdsmouth method. No spruce to be found so I used western red cedar and redwood, came out nice and light, and has withstood 20 mph + gusts with no hint of trouble

[brerrabbit]

Birdsmouth method looks HARD

Considering for my Lapwing.....any tips or howtoo's to be aware of?

[ChrisObee]

http://www.duckworksmagazine.com/08/howto/birdsmouth/index.htm

I've never made one but I've heard many say it was easier than it looked.

[Peter HK]

Maybe prices are different in the US but the materials for a birdsmouth mast here in Australia (local hoop pine - about equivalent to Douglas fir, same density and a little stronger) would have cost about 25 % more than 2 sizes of aluminium tube with a wooden top mast which is what I used. The other factor that I think is important is the weight of the finished spar with respect to lifting and fitting into the mast tube- my CS 17 mast is quite OK but approaching the upper limit of comfort. It might be worthwhile to spend a bit more time/money to get a lighter mast for a CS20, not from the performance point of view but for ease of rigging.

If I did it again I would use aluminium for the lower half (10 ft for a CS17) and birdsmouth for the topmast in a 2 section mast. Birdsmouth isn't hard at all but just a bit fiddly.

Cheers

Peter HK

[Howard]

For all these masts, is there a reason you can't use aluminum for the whole thing....top section included? Just use a wooden plug at the masthead for sheaves etc?

[hokeyhydro]

For all these masts, is there a reason you can't use aluminum for the whole thing....top section included? Just use a wooden plug at the masthead for sheaves etc?

On my plans for smaller CS boats Graham has details for all-aluminum masts and wood as well.

Be interesting to have the actual weight of finished aluminum masts for a CS boat. Birdsmouth wood can be fairly light. The catamaran mast I built runs about a pound a foot with all attachments, and built a couple BM shafts for paddles my daughter uses on the stand up paddleboard I built. The pro at the SUP shop in town was amazed at how light the paddles were. The slightly over 6' paddle my daughter uses weighs 22.5 oz which is only a couple ounces heavier than a commercial graphite paddle that cost about $400.

[hokeyhydro]

If I did it again I would use aluminium for the lower half (10 ft for a CS17) and birdsmouth for the topmast in a 2 section mast. Birdsmouth isn't hard at all but just a bit fiddly.

Cheers

Peter HK

I like that idea, Peter. Two piece for ease of transportation and storage & 1/2 wood to save a few AL $.

[Peter HK]

Be interesting to have the actual weight of finished aluminum masts for a CS boat

My 3 part mast for a CS17 has a slightly thicker-walled section than specified for the bottom 8 ft, then the standard midsection and then a solid wood (hoop pine) topmast. I worked out I would only save about 100gms (3 oz) by doing birdsmouth for the top section as it's only 6 ft long and either end needs solid wood plugs, so I didn't bother.

It's also a foot longer than design specs ie just under 21 ft. Total weight with blocks/halyards/track etc was 9.5 kg (21 pounds)

Cheers

Peter HK

[PAR]

When I built a CS-17, I made a slightly different materal arrangement then the plans. I made a single aluminum lower section and a tapered birdsmouth upper section from white spruce. This saved the bother of a two piece aluminum lower section, with their bushings and all, plus the track ramp. The main's lower section was about 12' and the wooden upper section was about 7', with a 12" bury in the aluminum section. The mizzen was done the same way, though the aluminum section was shorter, but the upper section was the same length. Technically, the mizzen is slightly "softer" then the main because of this, but not a signifigant amount.

Birdsmouth spars are easy to build. It's important to use a light, straight grained species or any advantage of this method is voided. Douglas fir is the very upper end of accaptable and I wouldn't use it at all on small spars and small craft. In larger sizes (3.5" and up, base diameter) then Douglas fir becomes more desirable. Lots of folks use Douglas fir, but there's a huge weight difference over the other "usual suspects". For example a birdsmouth main for a CS-17, built to plan specs, will be just over 10 pounds in white spruce. It's about a 14 pound mast in Douglas fir. This doesn't seem like much, but the weight is centerabout 10' above the boat, where it makes a bigger diffeence, then you'd think.

[Peter HK]

For example a birdsmouth main for a CS-17, built to plan specs, will be just over 10 pounds in white spruce. It's about a 14 pound mast in Douglas fir. This doesn't seem like much, but the weight is centerabout 10' above the boat, where it makes a bigger diffeence, then you'd think.

I presume you are talking about a mast blank rather than a mast with all fittings/halyards/tracks etc ready to put in the mast tube and go sailing. If so what was the weight of the finished mast with all fittings/halyards etc done with spruce (which I can't get without a lot of expense ). It would be nice to know with respect to the weight of the 3 part aluminium/wood mast (with all fittings) as I have posted.

Hope you can help

Cheers

Peter HK

[tom151]

On my plans for smaller CS boats Graham has details for all-aluminum masts and wood as well.

Be interesting to have the actual weight of finished aluminum masts for a CS boat. Birdsmouth wood can be fairly light. The catamaran mast I built runs about a pound a foot with all attachments, and built a couple BM shafts for paddles my daughter uses on the stand up paddleboard I built. The pro at the SUP shop in town was amazed at how light the paddles were. The slightly over 6' paddle my daughter uses weighs 22.5 oz which is only a couple ounces heavier than a commercial graphite paddle that cost about $400.

I need to make a SUP paddle for my daughter too

Would really appreciated details on the one you made - if you would be so kind to share detailed dimensions and construction picures if possible.

Thanks

TomH

PS did you build the board as well? If so, what plans did you decide to use?

[hokeyhydro]

On my plans for smaller CS boats Graham has details for all-aluminum masts and wood as well.

Be interesting to have the actual weight of finished aluminum masts for a CS boat. Birdsmouth wood can be fairly light. The catamaran mast I built runs about a pound a foot with all attachments, and built a couple BM shafts for paddles my daughter uses on the stand up paddleboard I built. The pro at the SUP shop in town was amazed at how light the paddles were. The slightly over 6' paddle my daughter uses weighs 22.5 oz which is only a couple ounces heavier than a commercial graphite paddle that cost about $400.

I need to make a SUP paddle for my daughter too

Would really appreciated details on the one you made - if you would be so kind to share detailed dimensions and construction picures if possible.

Thanks

TomH

PS did you build the board as well? If so, what plans did you decide to use?

Built the SUP - a Kaholo from CLC plans (Chesapeake Light Craft). Board came out heavier than CLCs advertised weight of 32 lbs, and many other builders had the same result = about 40 lbs. For the SUP paddle I made a teardrop shaped blade from two layers of 1/4" balsa wood. I used C grain balsa available from Sig Manufacturing, but I don't think C grain is absolutely necessary. Blade sheathed in 4oz fiberglass. Shaft was 7mm X 14mm western red cedar blanks with BM groove cut in one side and then I planed a taper on the handle end. I get some pics up soon, and you can email me wjhuson43@gmail.com for more details.

[Randy Jones]

Jim

I've got solid laminated doug fir mast on my CS17. They look great, but with the sail and boom attached they can be a handful to unstep when I'm cold and tired. I would think twice about going solid with a CS20 masts unless you're a youngster.

[Peter HK]

I've just worked it out that a 3 piece aluminium/wood topmast mast blank with solid hoop pine (equivalent to doug fir)would be 12 lbs - probably just under 11 with spruce as the top mast. Birdsmouth would bring it to about 10 lbs. It's still a nice light option.

Cheers

Peter HK

[PAR]

I should add that the birdsmouth specs, offered in the CS-17 plans will produce a fairly bendy mast, compaired to the aluminum arrangements also shown in the plans. I'd origionally intended to build all birdsmouth masts for this boat, but after talking it over with Graham and his views on the wooden versions he's seen, I elected to use the single aluminum lower and birdsmouth upper sections. I think my masts are much simpler to make and look better too.

[tom151]

Built the SUP - a Kaholo from CLC plans (Chesapeake Light Craft). Board came out heavier than CLCs advertised weight of 32 lbs, and many other builders had the same result = about 40 lbs. For the SUP paddle I made a teardrop shaped blade from two layers of 1/4" balsa wood. I used C grain balsa available from Sig Manufacturing, but I don't think C grain is absolutely necessary. Blade sheathed in 4oz fiberglass. Shaft was 7mm X 14mm western red cedar blanks with BM groove cut in one side and then I planed a taper on the handle end. I get some pics up soon, and you can email me wjhuson43@gmail.com for more details.

Bill,

Thanks for the help with materials and specs... the paddles _really_ look great.

TomH