Mast substitute?

The place to discuss SCAMP (Small Craft Advisor Magazine Project), our 11' 11" micro minicruiser.

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Marc
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Mast substitute?

Post by Marc »

PresentlyBuilding Scamp 319 I was wondering if I could use the the mast of my Bombardier 3.8.
it is long enough and is in two parts much like duckworks product. However I will measure thickness and diameter and post those measurements. We can then compare with other information out there.
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Re: Mast substitute?

Post by Marc »

The Bombardier 3.8 ( Laser clone) aluminium mast is 63,5 mm diameter and the metal thickness is 3mm
so it is slimmer than SCAMP's whose plans -for a wooden mast- state 76 mm diameter at base and 53mm at the top

Anyone knows if although slimmer an aluminium mast is strong enough (note: Scamp has more sail surface than the Bombardier?

Can anyone provide Duckworks aluminium mast diameter and metal thickness measurements?
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Re: Mast substitute?

Post by Marc »

Sorry : I meant Gig Harbor's mast , not Duckworks, and it is fiberglass,
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Re: Mast substitute?

Post by Marc »

thw boat is fiberglass, the mast is aluminium.
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simeoniii
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Re: Mast substitute?

Post by simeoniii »

Marc,

The material to use is 2.75”OD, 2.62”ID 6061-T6 alloy as spec’d by John Wesford. I guess that is a wall thickness of 0.13” or a little over 0.125. This is what the GH mast is made of. 2-pieces and non-tapered. 10'+ 6'-6" or 12'+4'-6" or something like that.

Are you planning on making your own? A two-piece mast that would be sleeved together solid or a break apart for trailering? Wooden plugs in the end, powder coat it.
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Marc
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Re: Mast substitute?

Post by Marc »

Thank you for the information.
Yes I am planning to build the mast and spars but I would like a 2 part mast. I thought the only way was aluminum. Maybe a ...hum...folding mast hinges at the middle portion?
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simeoniii
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Re: Mast substitute?

Post by simeoniii »

Yes, 2-part out of aluminum. At the join area you need an internal sleeve of smaller diameter tubing that is bonded and riveted in place in the lower section. That sleeve protrudes above the lower section and it is inserted into the upper part of the mast. The two are keyed together to prevent rotating action.

The right hand side in the photo is the lower section. You can see the two pop-rivets into the sleeve. You can see the keying rivet area. The rivet went missing. I was just about to add a new rivet when I took this photo. I hope this helps you visualize the setup.

You would also want to sleeve the lower section from the base up to about 18” above the cabin top mast box to reinforce that area.

363AAFFD-87A5-400B-BFB9-5B981336D5F1.jpeg
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Marc
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Re: Mast substitute?

Post by Marc »

thank you
I will go to a local shop and ask if they can do that.
Do you know of anybody who tried a hinged foldable lockable wooden mast?
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simeoniii
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Re: Mast substitute?

Post by simeoniii »

B52824F6-3575-4847-A535-B1C8864E4F7C_1_201_a.jpeg
No. I certainly wouldn't trust one, especially a freestanding unstayed mast.

There is at least one SCAMP that has a cabin top tabernacle that allow the mast to fold down on the fore-aft axis. Something like that could be designed so that when folded aft, a pinned mast base could be released and the mast then slide forward in a collar so that it could then be centered over the SCAMP, protruding a couple of feet forward and aft of the boat. That would be an interesting concept.

Click out Lonnie Black's Li'l SCAMPer in Florida.
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Last edited by simeoniii on Thu Apr 08, 2021 11:02 am, edited 1 time in total.
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Marc
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Re: Mast substitute?

Post by Marc »

Oh that is interesting indeed. I can t see if this is a one or two part mast but here is my thinking:
2 part mast
Part 1 , the bottom part ,say 6 feet long , is the female part and permanently remains inside, say only a foot protruding above;
Part 2: the male part, say 10 feet long plus 1 foot sliding into the bottom part

When trailering , two options
A: remove part 2, and place it horizontally on part 1 at 90 degrees ( the whole horizontal length should be within the 12 foot boat if I calculate correctly).
The support at the joint at the 90 degree angle could be a simple Y boot slipped into Part 1 into which part 2 fits, all strapped together; support fore and aft? Thinking about it ...

B: easy: part 2 lays alongside the boat, say the starboard side to get it off and put it on away from the traffic, and strapped there;
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