They aren't Triumph. They were shared with one of the bubble cars and a DKW. DKW were one of the 4 companies that became Audi and were the source of the logo - The D in there means dampft, the German word for steam - but has in the past been mis-translated to water and some people have written that DKW made the Amphi, anyway, back to the point ...
Both the DKW and the bubble (can't remember which) are rarer than Amphi so not many wiper arms about. I think the shortage is because people would cut them to fit different blades. I'll have a look at what I've got, I'm pretty sure they were different LHD to RHD, Amphicar took the trouble to change all the wiper linkages - amazing amount of work for just 98 cars !!!
David C
----- Original Message -----
From: Amphicarbudd
To: david@manbus.com
Sent: Thursday, October 30, 2008 7:21 AM
Subject: RE: [General Amphicar Discussion-t-20223] Re: Looking for a Windshield Wiper Arm
hi ted-when i get to ca ill look in my pile-when i was dismantling i recall doing a triumph convertable about 57 or 58 and the arms looked similar and i saved them-finding them is a horse of a different color-im still sooking for my handles i had rechromed. ill look within the next couple of weeks as ill be heading south. thanks for information re brakes. i bought the vw mc new online and for some reason-probably because of nos statrus it would not work without leaking, which brought me to go and try to dual cylinder at this time-ill letyou know if i can locate arm, and also if my dual effort works out----thanks again brad anderson island