What is "draft"?

When looking at manufacturer's draft specs on a boat, what does the draft measurement determine? Is the draft depth measured with the boat at rest? or on plane? empty? at max capacity? or perhaps the deepest draft of the boat at any given time, angle, or weight? I know it has nothing to do with beer, although several cases of beer on a boat may cause a deeper draft.

Re: What is "draft"?

Draft is the depth of water a boat needs to float when at rest without cargo or passengers.
http://en.wikipedia.org/wiki/Draft_%28hull%29

Re: What is "draft"?

well good question;
i had always conisidered it to be the water line down to the lowest point on the boat in the water. with the boat at rest or docked. or the minium amount of water .you would need to float the boat

after you ask, i cant swear thats the right answer.

Re: What is "draft"?

The draft (or draught) of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel), with the thickness of the hull included; in the case of not being included the draft outline would be obtained. Draft determines the minimum depth of water a ship or boat can safely navigate. The draft can also be used to determine the weight of the cargo on board by calculating the total displacement of water and then using Archimedes' principle. A table made by the shipyard shows the water displacement for each draft. The density of the water (salt or fresh) and the content of the ship's bunkers has to be taken into account. The closely-related term trim is defined as the difference between the forward and after drafts.

ok; i copied this from breskins link above. the question i have now; it does say to the water line to the keel with no provision for under water gear or drives- rudders that might hang below the keel.
is it common on large ships, for the keel to be thee lowest point of the ship? with nothing hanging below.
or does it come from sailing ships where the keel was the lowest point and before power- props ect?
almost all pleasure craft i know of have drives or props that hang below the bottom of the keel. wouldn't these require draft or be considered into the draft of said craft?

Re: What is "draft"?

almost all pleasure craft i know of have drives or props that hang below the bottom of the keel. wouldn't these require draft or be considered into the draft of said craft?

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Yes, My tug is 3'6" with the outdrives all the way down.

Re: What is "draft"?

good beer

Re: What is "draft"?

paultjohnson said:

good beer

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good thinking

Re: What is "draft"?

jaxnjil said:

is it common on large ships, for the keel to be thee lowest point of the ship? with nothing hanging below.
or does it come from sailing ships where the keel was the lowest point and before power- props ect?
almost all pleasure craft i know of have drives or props that hang below the bottom of the keel. wouldn't these require draft or be considered into the draft of said craft?

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Large ships have the keel at the lowest point.
If you look at the specifications for I/O-powered pleasure craft, they will specify two drafts: one with drives down and another with drives up. Inboards have only a single draft specification that is based on the lowest point, usually the rudder or props.
The goal of a draft specification is to instruct the operator on the minimum navigable water depth.

Re: What is "draft"?

On boats with fixed running gear (non-adjustable props and/or rudders and/or non-swinging keels), the term draft is used to determine the minimum amount of free water necessary to keep you from burying yourself in the sand.

Re: What is "draft"?

Fireman431 said:

the term draft is used to determine the minimum amount of free water necessary to keep you from burying yourself in the sand.

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If you had kids you'd know that they won't drink free water, but they don't need any to bury themselves in the sand . . .