MattandTru Posted August 25, 2014 Report Share Posted August 25, 2014 My son and I are planning a CS 17 build and would love to hear the pros and cons of wood vs aluminum masts from all you veterans. I've looked at the mast building technique that B&B offers/suggests and it makes sense and seems affordable, but are there options to consider? Also has anyone adapted spars from any other boats to serve the 17? -Matt and Truman Quote Link to comment Share on other sites More sharing options...
PAR Posted August 25, 2014 Report Share Posted August 25, 2014 All wood masts wouldn't be my recommendation, as they'll be a wee bit bendy with the stock dimensions, though relatively light. The composite mast (2 aluminum lower sections, with a birdsmouth upper) is quite light, but I personally have issue with the two piece aluminum element of this. I elected to make a single aluminum lower section with a birdsmouth upper section. This saved the tapering and fitting of the two aluminum sections and allowed a taper on the longer upper section, with my version to save weight and get some looks from the sticks. The only reason to make an all wooden mast is if it's to be varnished (way over rated BTW). Nearly every wooden mast I've seen for the CS series bends off much more than I'd like to see, compared to the composite shown on the plans or my modified version. There aren't a lot of "production" boats with free standing masts of sufficient length and diameter, so choices are limited. Also these masts are usually extrusions, often with some features, such as a bolt rope groove, maybe a tear drop section, etc. None of these can be used in a free standing rig, further limiting your choices. The CS-17 masts are one of the easiest elements of the build to tackle. Quote Link to comment Share on other sites More sharing options...
Lynn Watson Posted September 1, 2014 Report Share Posted September 1, 2014 Everyone seems to agree that wood masts are too floppy, built to design dimensions. So the inquiring mind wants to know: how much to increase the x-section of the mast to get a good flex profile? Your composite stick sounds very efficient, but I just enjoy working with wood so much better than with metal... Could you make an estimate of what would seem right in, say, VG fir for a Belhaven mainmast? Here are the specs given in the plans -- 3 1/2" dia from heel up 6', then tapering to 2" at masthead; 20% wall thickness (3/4 stock) birdsmouth construction, 20' total length with 21" bury in the tabernacle. On another note, would a strip of unidirectional carbon tape on the insides of the birdsmouth staves make any sense? Thanks for indulging my curiosity, Lynn Quote Link to comment Share on other sites More sharing options...
Designer Posted September 1, 2014 Report Share Posted September 1, 2014 Lynn, The above information is incorrect. If you make a wood mast to the same diameter as our typical aluminum mast, it will be clearly under strength. As you noted, the Belhaven main mast shows that the wood mast is a half inch larger in diameter than the aluminum version. This will have similar strength properties to the aluminum mast. I say similar because, as you know wood strength varies from species to species and from tree to tree plus the workmanship factor. For builders who are just looking for a cheap mast, wood is not the way to go. Unless you get a real good deal, wood costs about the same as aluminum, takes a lot more work to build and requires much more care than aluminum. I have to replace my wood upper mast sections on Sc because they rotted out. They were birdsmouth fir covered with carbon braid. They worked perfectly and took all of the abuse that I gave them except for lack of maintenance. I never got around to protecting the epoxy coating by painting them. Even with the boat under cover, the masts stuck out in the weather more than I thought. The sun must have burned enough epoxy away to allow water into the end grain. I am going to replace them with aluminum and be done with it. Quote Link to comment Share on other sites More sharing options...
Designer Posted September 1, 2014 Report Share Posted September 1, 2014 I forgot to mention that wood masts are heavier than aluminum. Quote Link to comment Share on other sites More sharing options...
Lynn Watson Posted September 1, 2014 Report Share Posted September 1, 2014 Okay, Graham, I take your point! Thanks for the input. Hope you can make it out to Port Townsend for a festival again sometime. cheers, Lynn Quote Link to comment Share on other sites More sharing options...
MattandTru Posted September 1, 2014 Author Report Share Posted September 1, 2014 Thanks to you all. I'm convinced! Lighter, just as cheap or cheaper, less work, last longer. OK, I get it! -Matt Quote Link to comment Share on other sites More sharing options...
wwbaginski Posted September 3, 2014 Report Share Posted September 3, 2014 A question: if there's an aluminium mast which consists of 2 or 3 tubes of different diameter each, and there is a part of the sail track mounted to each tube, how to assemble those tracks while assembling said tubes, to get one long smooth working sail track assembling them to get one long smooth working sail track? A photo illustration would be much appreciated too. Quote Link to comment Share on other sites More sharing options...
Mike Vacanti Posted September 3, 2014 Report Share Posted September 3, 2014 In one of Alan's excellent videos that describe his build of a CS 15 (#12, https://www.youtube.com/watch?v=MiTKRlCRQq4&index=13&list=PLCCJRycps-_mbO-Lfdr0s8OZX-4QOZCzL), he specifically addresses this issue. He builds a ramp out of fiberglass to make a smooth transition from the larger to the smaller tube. Quote Link to comment Share on other sites More sharing options...
Docpal Posted September 3, 2014 Report Share Posted September 3, 2014 This is one way to do it. I just used fiberglass tape and criss crossed it both ways over the "step". Then I wet sanded the joint with 40 grit paper (really cuts smooth and fast that way...). Followed that up with some micro balloon filler for the final finish, and then primed and painted it all. I think the last picture is where the joint was, but I can no longer tell.... Quote Link to comment Share on other sites More sharing options...
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