30+ Plans PDF

The Thirty + is one of Joe Dobler's better known large trimarans. It was originally designed for and built with plywood, but was soon put into production as a fiberglass model. Aparently the FG version was never as fast as the wood prototype, though which may explain why only a dozen or so were made.

Joe's son-in-law, Tom Setum, has been slowing sorting through the stacks of drawings that he inherited and sending what he considers to be complete plans to us to make available to builders. These 30+ plans are for the original plywood version (though there is one overview of what is thought to be the production model) and are believed to be complete.

I have convinced Tom to make these plans available at what amounts to a fire sale price. After all these plans are dated and a lot of progress has been made on multihulls in the years since the 30+ was designed. My thought was that this is a piece of history and worth study by anyone interested in modern cruising trimarans. Below is a list of the drawings that come with the plans - you can see that the cost of the drawings alone is significant.

"THIRTY PLUS" Design #176 by Joseph C. Dobler

176 - 1 Three View, (1/10/1968) (24 x 36)
176 - 1a Three View, FRP version (10/16/1968) (8.5 x 11)
176 - 2 sht 1 Main Hull & Float- Lines; (2/29/1968), (24 x 36)
176 - 2 sht 2 Main Hull & Float — Offsets; (3/1/1968), (12 x24)
176 - 3 sht 1 Main Hull Construction; (3/15/1968), (24 x 36)
176 - 3 sht 2 Main Hull Construction (3/15/1968), (24 x 43)
176 - 4 Beam & Fairing Construction (5/13/1968), (24 x 36)
176 - 5 Centerboard & Rudder (5/17/1968), (24 x 36)
176 - 6 Float & Platform Construction (4/17/1968), (24 x 36)
176 - 21 Sail Plan & Rigging (5/23/1968), (24 x 36)
176 - 22 Spars Specification DWG (5/24/1968), (24 x36)
176 - 102 Sliding Door for Outboard Motor Well - GA (7/11/1968), (24 x 36)
176 - WM Wing Mast System (5/1982), (17 x 22)
176 - Rudder Box — Swing — Lift Rudder (11 x 17)
176 - Rudder (3/5/1982), (11 x 17)
176 - Rudder Blade — Swing Lift Rudder (11 x 17)
176 - Bow Fig - ¼” bow plate & angle drawing. (8.5 x 11)
176 - Stringer detail (8.5 x 11)

Note:
1. "30 P1us" Joseph C. Dobler's design # 176 was first built by wood construction and shortly after was built of all FRP.
2. 176 - 1a Three View, 10/16/1968 is shown for info. It is probably is the "all FRP" version. It shows a V bottom float and one hatch per float. It has different interior arrangement and the 30 + insignia on the sail.
Dobler design #176 _ T. J. Setum

Here are excerpts from the brochure that came with the production fiberglass version of the 30+: