Tad Roberts

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Red Cedar 28' Family Coastal Cruiser

Construction:
Length: 28' 0"
Beam: 9' 6"
Draft: 17.5"
Displacement: 7,800 lbs (half-load)
Power: 330 HP outdrive
Cruising Speed: 25 Knots
Builder:

Comments

This hullform, often called the modified vee or variable deadrise hull, is my favorite shape for a moderate speed planing boat. It is a compromise, with fine, deep, forward sections, similar to the deep-vee, becoming much flatter and wider aft. Red Cedar has 14 degrees of deadrise at the transom, so we sacrifice the ability to blast off the tops of waves at 30+ knots. But we do have a hull that gets up on plane quickly and runs there economically. At a cruising speed of 26 knots Red Cedar needs about one horsepower for every 39 lbs of boat, whereas Sitka Spruce with her deep-vee hull needs one horsepower for every 28 lbs of boat. Part of this economy is length, the longer a boat is the easier it is to push. Red Cedar also has a lower B/L (beam/length) ratio, .34 compared to .39 for Sitka Spruce. This eases out her lines, note the 1/2 angle of entry for Red Cedar's waterline, 17 degrees verses 20 for Sitka Spruce.

I have chosen a single large outdrive as Red Cedar's propulsion system. Though there are many choices, I believe this to be the best from an efficiency standpoint, ( appendage drag of single leg) and an economy standpoint, ( only one engine to buy, install, build beds for, etc.). Efficiency is an odd thing, sometimes the installation of a smaller engine produces a faster boat, by reducing weight and/or drag.

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