Low Tide

Yacht Designer Tad Roberts' Web Log

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Stability information presented to the public is usually simplified to the point of being useless. When I see a published stability curve like that above, my reaction is “That’s nice and it looks good, but it tells me almost nothing.” It’s a nice graphic but key information is missing, mainly data on the conditions under[.....]


Bluenose and Columbia raced against each other in only two races in 1923. Bluenose was then 2 years old and Columbia brand new. Bluenose won both those races but the committee awarded the second race to Columbia due to Bluenose rounding a mark improperly. Angus Walters took exception and left Halifax without the issue being[.....]



This article was originally published in Western Mariner November 2015.


This article originally appeared in Western Mariner September 2014.

Aluminum Tug Cruiser, T-Cup; a new design

T-Cup A 25’ Aluminum Power Cruiser LOA = 25’3” LWL = 24’0” Beam = 8’6” Draft = 2’7” Displacement to DWL = 6500 lbs Power = Yanmar 3Y30 Diesel Cruising Speed = 6.5-7 Knots Construction Plans and patterns = $750.00 T-Cup is a family cruiser in the “Tug-type” style. This boat is far closer to[.....]

Sheerline Problems

Many think the sheer is the most important line on any boat. Get it right and all else is forgiven, get it wrong and nothing else matters. To some extent this is true, this one line in 3D space, must be attractive when viewed from any angle. If it’s filled with humps and hollows from[.....]

Change in Stability with Dinghy Aboard

I’m often asked about the advisability of adding a heavy dinghy stored on the roof, people wonder how much difference this will make to stability. The answer always involves a lot of questioning about the particulars of the boat and load condition. So today I made a study of a typical 1985 “trawler” yacht, the[.....]

The Cogge Nonsuch

In 1916 Douglas P. Urry was serving (probably RCN) in the North Sea. While reading off watch he came across mention of “the Cogge Thomas,” and started to wonder what that ship might look like. He wrote to his brother, F. Wavell Urry, in Vancouver, and Wavell started sketching. These drawings are the result, the[.....]

Sakamoto Brothers Boatbuilding at Osland

Above is the beautiful gillnetter Bee, built 1933 at Osland. She might be double-ended or round-sterned, but hard-chined (vee-bottom) which is very unusual. It’s launching day. There’s another boatshop in the background, along with one or two houses and a substantial deer fence. This may be one of the earliest streamlined pilothouses. Photo from the[.....]