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Price Drop. We hate to see our girl sitting on the hard and have dropped the price in the hopes she will be put to good use in the 2023 season. Reasonable offers will be considered. For sale: 1981 ODay 30 Draft- 5 Beam- 11 Fin keel Keel stepped mast w/ internally-run halyards Universal atomic diesel (universal 5416) serviced professionally every haulout/launch. No issues with this engine aside from airlock upon recommissioning last season. Problem was resolved. It’s about time for a new heat exchanger but not vital. New sails 2021-old sails still in good shape Lazy jacks new and installed 2021 New stainless steel life lines 2021 Bilge cleaned painted 2021 Replaced cabin shelves 2021 New Garmin chart plotter 2021 New running rigging 2020 Standing rigging inspected 2020 Thorough bottom job 2021- painted with micron 66 Gelcoat topsides and deck buffed/waxed annually New canvas- stack pack, dodger, mast skirt GPS cover Lifesling new 2021 canvas cover to match Self-tailing winches All thru-deck fasteners removed, bored out, filled with epoxy and re-bed 2021 35lb galvanized Mantus M1 anchor new 2021 New chain/rode 2021 Replaced mast wiring 2021 Added all LED deck/steaming combo light and tricolor light 2021 2 house and 1 starting battery, small solar panel on aft pulpit has always met our needs for coastal cruising. Replaced forward/chain locker bulkhead 2021 New manual head 2019 Inflatable Avon hard bottom dinghy and outboard in great condition No soft spots. Althea has been a safe and comfortable boat for cruising the coast of Maine. We are sad to let her go but it’s more important that she continues to be sailed and cared for. She is currently shrink-wrapped and on the hard from last season. More pictures available upon request. Reasonable offers and serious inquiries only, please.
The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.
Classic hull speed formula:
Hull Speed = 1.34 x √LWL
A more accurate formula devised by Dave Gerr in The Propeller Handbook replaces the Speed/Length ratio constant of 1.34 with a calculation based on the Displacement/Length ratio.
Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio.311
Hull Speed = Max Speed/Length ratio x √LWL
A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.
SA/D = SA ÷ (D ÷ 64)2/3
A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.
Ballast / Displacement * 100
A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.
D/L = (D ÷ 2240) ÷ (0.01 x LWL)³
This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.
Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)
This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.
CSV = Beam ÷ ³√(D / 64)
A keel/cb model was also available.
Draft (board down): 7.18’ / 2.19m
Draft (board up): 3.50’ / 1.07m
Displacement: 11,000 lbs / 4,990 kg
Ballast: 4,700 lbs / 2132 kg
Tall Rig:
I: 41.50’ / 12.65m
J: 13.50’ / 4.11m
P: 35.50’ / 10.82m
E: 10.25’ / 3.12m
Reintroduced (with extended stern) as O’DAY 31 (1985).
Similar to the RANGER 30.
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