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April/May 2017 — Table of Contents

Cover of latest issue of Professional BoatBuilder magazine.

On the cover: A new wooden shaft bearing is being installed in the harbor
tug Paletuvier at Classic Works in La Ciotat, France. It was custom-built from lignum vitae staves machined to a close fit with the 240mm-diameter (9.5″) shaft and fitted inside a bronze sleeve as a quick, long-lasting replacement for a failed conventional modern rubber bearing. Story on page 40.
Photograph by Butch Dalrymple-Smith.


Dave Clark

Designing a production foiler. Page 22.

22  The People’s Foiler
by Dave Clark
The father-and-son design team of Steve and Dave Clark develops the UFO, a stable, affordable, production-built foiling beach catamaran.

Robin Loscombe

Simplified equations. Page 31.

31  Taking the Simple Measure of Laminates
by Robin Loscombe
Simplified equations allow designers to calculate symmetric orthotropic
panel-bending moments without resorting to finite element analysis.

Butch Dalrymple-Smith

Lignum vitae shaft bearing. Page 40.

40  Saved by the Wood of Life
by Butch Dalrymple-Smith
A client’s looming towing contract forces a yard to look to the past for
materials and techniques in replacing the shaft bearing of a harbor tugboat.

John Kecsmar

Wind farm tenders. Page 48.

48  Waiting on the Wind
by John Kecsmar
The challenges of weighing competing practical, technical, and regulatory demands when designing crew-transfer vessels for offshore wind farms.

Courtesy Norsafe

Norsafe RIB at HSBO. Page 64.

64  RIB on the Göta älv
by Paul Lazarus
At HSBO 2016, venerable Norwegian builder Norsafe brought its Marathon 900 (9m/30′) RIB, powered by a pair of Mercury OptiMax diesel outboards.


6 Letters, Etc.
A reader comments on refining inclining experiments; and Lorne Campbell analyzes end-swapping.

12 Rovings
compiled by Dan Spurr
Two generations of Rickborn innovations; nonpolluting-shaft-bearing solutions; Epoxyworks achive accessible; Cowes–Torquay races recalled; Paul Elvstrom and Dave Sintes pass; and Tacoma Community Boat Builders.

80 Parting Shot
by Steve D’Antonio
The need for trained boat builders and maintenance techs has grown steadily since the recession, but industry leaders have done little to create the apprenticeship programs that could help meet the demand.


73  New Products and Processes

74  Connections

77  Classified Advertising

79  Index to Advertisers