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Chopper Guns
Posted: Wed Jul 12, 2006 5:26 pm
by Mark Prouty
Discussed fiberglass repair with two shops. Both shops thought that the Mac was built with
Chopper Guns
Most of our competitors use "chopper guns" to build their boats. These are devices for spraying a mixture of resin and very short strands of fiberglass. We don't use them, even though they reduce cost. They do not, in our opinion, give adequate impact strength or controllable hull and deck thickness. They result in heavy laminates with low fiberglass to resin ratios, accounting for much of the excess weight found in many competitors boats. Light weight is the key to easy trailering and to high performance.
Bad rep? Do any boat manufacturers still use chopper guns?
Is
Most of our competitors use "chopper guns" to build their boats.
BS?
How strong is Mac fiberglass? The sides sure seem to bend in and bounce back on impact. Why is this? Good or bad?
Posted: Wed Jul 12, 2006 5:43 pm
by They Theirs
I was impressed with the survival of hulls swept up in the past hurricanes, and the Mac filled with water on the trailer that had survived previous incidents. There are many reports of Mac's surviving some tough hits.
Posted: Wed Jul 12, 2006 5:53 pm
by kmclemore
That latter picture, above, is not a chopper gun... they're spraying gel-coat, a pretty common way of applying that stuff, and it has no effect on strength. The first picture, however, shows layup with cloth, and indeed that is the way I believe the outer hull is made on the Mac. However, truth be told, I think, like most boats, the Mac was made with a mix of approaches. Where strength was needed, they tended to use cloth - less than other boats, but plenty to do the job- and there's a lot of other parts - and even parts of the bilge - made with chopper guns.
How strong is Mac fiberglass? The sides sure seem to bend in and bounce back on impact. Why is this? Good or bad?
Well, would you like to see your boat give a bit and bounce back, or rather have it stay nice and hard and take a huge gouge or, worse yet, crack?
Simply, it's as strong as it needs to be. I'm not worried. How many Mac's have you seen go down because of a busted hull?
Posted: Wed Jul 12, 2006 6:07 pm
by Catigale
LOts according to the experts on Sailing Anarchy...and of course they cant refute that it didnt happen, as they are all lost at sea...
I thought somewhere in the 2002 material Roger made a statement that chopper guns are not used anywhere BICBW....
Posted: Wed Jul 12, 2006 6:12 pm
by kmclemore
Catigale wrote:"... Roger made a statement ...."
Ahh... I see the critical flaw in that argument....
Hey, how do you know when a car salesman/lawyer/consultant/boat maker/you-name-it is lying?
His lips are moving.
Posted: Wed Jul 12, 2006 6:15 pm
by Catigale
BRutal!!!
...but no way Im putting Roger in with the lawyers...thats too low Kevin...
Posted: Wed Jul 12, 2006 6:17 pm
by kmclemore
Catigale wrote:BRutal!!!
...but no way Im putting Roger in with the lawyers...thats too low Kevin...
Apologies. And hey, I even have a brother that's a lawyer. I should know better.
Posted: Wed Jul 12, 2006 7:02 pm
by Catigale
Three Engineers and Three Lawyers are on the Acela to NYC, and the lawyers realise the Engineers only have a single ticket between them.
What are you going to do? THey ask. "We have it covered" say the engineers...
Sure enough, when the conductor comes around, the engineers cram into the head, the conductor taps on the door and says "ticket please", a single arm comes out with a ticket. and they make the trip ok.
The lawyers are fuming that they bought three expensive tickets, and on the return trip, come back with a single ticket.
..But the engineers dont have any tickets for the return, and insist they have it covered again, with no ticket.
THe three lawyers quickly cram into the head, but just before the conductor comes, one of the engineers taps on the door and says..
"Ticket please"
Posted: Wed Jul 12, 2006 7:29 pm
by Divecoz
kmclemore wrote:Catigale wrote:"... Roger made a statement ...."
Ahh... I see the critical flaw in that argument....
Hey, how do you know when a car salesman/lawyer/consultant/boat maker/you-name-it is lying?
His lips are moving.
Ill look again Kevin But I don't think so its not all roving by any means but I haven't seen evidence of a gun
Posted: Wed Jul 12, 2006 8:08 pm
by kmclemore
Well, it's always difficult to tell for sure, but some bits to look like they were blown in on my boat.... not sure it's all just mat, rovings and tissue... but then I haven't been to the factory...
Posted: Wed Jul 12, 2006 8:27 pm
by Tom Root
I've been to the factory a half a dozen times since 1986 and unless they hide them just when I visit, no chopper guns were ever used! I have seen all phases of manufacturing too.... and at least as many models, OK five anyway!
Mat and roving is all I ever saw, and I have used chopper guns before, so I do know what to look for!
Posted: Thu Jul 13, 2006 7:01 am
by Don B
I think Skip has some experience with above water line hull integrity.
-DonB
Posted: Thu Jul 13, 2006 7:47 am
by LOUIS B HOLUB
Ive looked my Mac X over closely, before and since buying it. And since I did the same with my former boat, a Mac 26-S, I looked for thin spots, or "thin" layers and found none. Ive pounded the inside areas of the hull, crawling through, and looking & listening closely since Im a "stickler" for safety and quality. So far...Im quite happy with the Mac.
Interestingly, the manner that the Mac is secured together with the top side and liners, adds a lot of hull strength. After all--some have 140 Horses pushing this sailboat.
...140 horses, yeppers....its gotta be tough.
Happy Sailing...
No fluff in the goop
Posted: Thu Jul 13, 2006 10:24 am
by Night Sailor
No chopper stuff in my X. I've been all over it, and drilled a lot of holes. It's all laid up mat and cloth with resin. Not the smoothest job, but still solid. I used to make fiberglass waterskis and boats for Newsome Boat, and crafted interiors on custom yachts on the Durbeck assembly line, so I know what to look for.