A small bit o' Plastic: Thunderbird 8 dinghy

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CapnK
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A small bit o' Plastic: Thunderbird 8 dinghy

Post by CapnK »

A Craigslist deal, I've found very few references online to either these boats or their manufacturer, 'Snug Harbor Boat Works'. I picked it up yesterday and haven't splashed it yet, have to make a sail and rigging for it, but will try it out under power later this week. Mine was manufactured in 1977, and while perhaps not 'Classic', she is certainly old enough to be given some regard. ;)

It seems a bit heavier than the Walker Bay 8 I used to own, around 75#'s from what I've read. My intent, if the hull form works well, is to use it as a plug of sorts, basically wrap it in divinycel and glass, pop the result off and glass the interior. Doing that and going to leeboards, I think I could make it a nester, and likely halve the weight. :)

The Thunderbird was made in at least 3 sizes that I have seen:
  • a 7' (w/no daggerboard slot),
  • the 8' (my version),
  • and a 10' (no slot and an extra seat, see in-water pic).
Pics are from the CL ad (yellow boat), and the last 2 are from the blog (theincrediblehull @ blogspot).

These dinks were made in St Petersburg, FL (see pic of label) and it looks like the company went OOB in the late 80's. They are not related (that I know of) to the dealer/broker in GA that uses 'Snug Harbor' in their name.
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atomvoyager
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Re: A small bit o' Plastic: Thunderbird 8 dinghy

Post by atomvoyager »

The new Divinycell cored dinghy will be interesting to follow. Maybe you can document the steps of the build here. I've wanted to build a foam cored dinghy for years but haven't got around to it. Not sure of the optimal core thickness and glass type and amount to keep the weight down while still stiff enough. I've always used plywood as the core on my pram dinghies but here's a way to build lighter, never have rot, and allow easier curves. If using say 3/8" core then there is also significantly increased buoyancy if flooded. I'm guessing you'd need a minimum of two layers of 6oz cloth outside and one inside. But not sure if that's right so let us know what you come up with.
CapnK
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Joined: Thu Aug 25, 2005 10:28 am
Location: Winyah Bay, Georgetown SC

Re: A small bit o' Plastic: Thunderbird 8 dinghy

Post by CapnK »

That's about what I've been thinking, James. Many years ago I worked in the surfboard industry, even had my own brand, and via that was fortunate enough to get to spend two winter seasons working at the premier glass shop on the North Shore. The really cool thing was that the guys I worked with and for out there were the top shapers and riders in the world - Merrick, Rusty, Byrne, and their team guys like 11 time world champ Kelly Slater, Rob Machado, the Ho brothers, etc... Anyway, I plan to use some of that knowledge. Hull of 3/8 foam, doubled at gun'l and transom. 6 to 10 oz glass, layered on stress/wear areas. Keep it light as possible, but sturdy where needed. Working on getting material funds together so that when the weather turns a little drier I can get to work on it ASAP.
Kurt and Barque, the CrewDog.
Sundance, '71 A-30, #429
Katie Marie, Ariel #422
Melelani, Islander 36 (shoal)

sailFar.net - Small boats, Long distances...
CapnK
Site Admin
Posts: 251
Joined: Thu Aug 25, 2005 10:28 am
Location: Winyah Bay, Georgetown SC

Re: A small bit o' Plastic: Thunderbird 8 dinghy

Post by CapnK »

Dinghy thinkin' continues...

Found this video of a dink built with a cored hull and some some carbon sheathing. At 10' LOA, her hull weight is only 34 lbs. Wow. :)
Design is by B&B, a Spindrift.

Video at https://www.youtube.com/watch?v=WGReTGNfSmE
Kurt and Barque, the CrewDog.
Sundance, '71 A-30, #429
Katie Marie, Ariel #422
Melelani, Islander 36 (shoal)

sailFar.net - Small boats, Long distances...
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atomvoyager
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Re: A small bit o' Plastic: Thunderbird 8 dinghy

Post by atomvoyager »

That is impressive weight for a 10' dinghy hull. He claims a 25% weight reduction from plywood, even though he used a plywood transom so that's good to know. The 34 lb hull weight will double or triple once all the rest is added but still is light. I learned more from the comments than the video and from his first video here:
https://www.youtube.com/watch?v=LFI5C-gPeOs
Turns out he used 5mm honeycomb Nidaplast or Nidacore. He said it was so floppy to handle that next time he'd precoat it with epoxy resin to stiffen it before assembly. I'd prefer using 10mm (3/8") foam core for stiffness and buoyancy. Interesting that he went with very thin core and expensive carbon to gain some impact resistance and stiffness. Looks like he never finished the build started 3 years ago so I don't know if that is related to some of his choices of construction. For example, I don't think I'd go with a wood transom and wood gunnels except maybe in oarlocks area.. Maybe use coosa if extra stiffness and compression strength was needed somewhere. I'd also cut cost on the choice of fiberglass because I'm not sure how much of an advantage the harder to work exotics are in this application. That said, I'm no expert on this so hope to learn more.
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