Sunfish Mast and Boom Specs

Thread starter #1
I am very new to the world of Sunfish. My daughter took sailing lessons and fell in love so I am restoring 2 Sunfish from 1966 and 67. I am considering manufacturing my own mast and spars but I don't know all the dimensions. I know that the mast should be 10' and 2 1/4" across but could someone tell me the thickness of the aluminum? I am also looking for the thickness of the aluminum for the boom and upper spar. Thanks for your time.
 

mixmkr

Active Member
#2
You'll get several answers, as this topic seems to be popular for people attempting to avoid freight costs and just ordering new. I've not looked but finding suitable substitutes may become a scavenger hunt locally. Depending on your location, there are some around here that have them for sale, if you're close enough for pickup. But the freight seems to knock the price out of the ballpark for many, looking for new or replacement spars.
Specifically answering your question, I don't have the exact answers...others will here. But, shedding some info on the subject overall.
 

L&VW

Well-Known Member
#5
Two points:

1) The aluminum you need is shipped to wholesalers in 20-foot lengths. Freight might not be too outrageous if you order one 20-footer.

Michigan may have a wholesaler near you; however, the furthest request for the new masts I'm selling, came from Michigan! :rolleyes:

2) Before ordering for two boats, check for absolute-certainty it is actual Sunfish you own. :confused:
 
#9
They're 6061 alloy, hard anodized. 6061 is one of the most commonly available aluminum alloys. I *believe* both Sunfish masts and spars are T6 heat treated (Laser masts and booms are 6061-T6, that is, 6061 alloy heat treated to T6).

Heat treating to T6 is commonly reported to increase 6061's mechanical strength by as much as 30%.
Aluminum Workshop: Achieving T6 designation for 6061
 
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#10
They're 6061 alloy, hard anodized. 6061 is one of the most commonly available aluminum alloys. I *believe* both Sunfish masts and spars are T6 heat treated (Laser masts and booms are 6061-T6, that is, 6061 alloy heat treated to T6).

Heat treating to T6 is commonly reported to increase 6061's mechanical strength by as much as 30%.
Aluminum Workshop: Achieving T6 designation for 6061
Thanks Roller. We manufacture dollies for dinghies and laser practice spars with this alloy and we are analizing to begin with sunfish class. But I believe to remember that in any place I read that the mast goes with 6061T6 but the booms in 6063T6 or 5. I would like to use the right alloy and we have a commercial heat treatment so we do it in house. I sail laser but know nothing about sunfish.
 
#11
Jotag--
I know you from the Laser forum and certainly respect your expertise. I have been told Sunfish masts and booms are 6061-T6, but I have never seen a stamped or stickered Sunfish mast or spar which specified alloy/temper, so without real information I am only repeating hearsay. 6063-T5 or T6 is certainly a possibility--who knows what "OEM" parts (likely from various sources) have been over the years. I think that with your Laser experience you are the experts here, and could produce Sunfish parts which equal or surpass those from "OEM"s.
 
#12
Thanks again Roller. I would like to test hardness of any good spars in order to realize about alloy type. But here in Argentina there is no sunfish boats. I have 35 years of experience in heat treatmets and before getting involved in spars matter I had believed that better alloy meant better quality. False. As we usuallu treat 7075 alloy (used in aerospacial use and much better alloy than 6061) for BERSA CAL 22 gun frames, and I think it would be better for laser spars. False. It is the hardest alloy and it doesn¡t allow the masts curve correctly. It is good for opti masts but not for laser.
That is why I am asking for the right alloy. 061 is harder than 6063 and I have never sail a sunfish to know what happen.
 
#13
Dear Jotag--
As you will know, Rig-Rite, Inc. (Kenyon Spars) is a well respected and long-time manufacturer of aluminum masts and spars.
(website at: Kenyon Spars Main Page )
They specify that "All Sections are extruded of 6061-T6 Aluminum Alloy, unless otherwise noted."

Kenyon does sell "Sunfish Spars and Common Parts". (see page at: Sunfish Spars & Components )
On this page they specify that "Sunfish Booms and Spirits use a 1 1/2" OD (.065" wall) Round Tube."
This extrusion is their "Kenyon Spars 1 1/2" Boom Section", which they specify as "Alloy: 6063-T6" (see this page: Kenyon 1 1/2" Round Boom Section )

So, I think you are correct. For this manufacturer at least, Sunfish masts are 6061-T6 and Sunfish booms are 6063-T6.
 
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