Todays problem
 

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

Todays problem
 

Gordon wrote:
You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

Depends on the boat (shape of hull, beam, etc.) Best to try it and then
see if it works.

Todays problem
 

"slide" wrote in message
...
Gordon wrote:
You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

Depends on the boat (shape of hull, beam, etc.) Best to try it and then
see if it works.

Aw, you beat me to it.

Todays problem
 

On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?


If x is the height of the transverse metacentre above the waterline (
assume it is fixed, for small angles of heel)..

(x+6) * (1 - cos(10 degrees) ) ft. at a guess.
(x+6) * 0.015 ft. Say a couple of inches..

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?

sufficient.

Todays problem
 

On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Todays problem
 

"Brian Whatcott" wrote in message
...
On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Two different boats:

Boat A has a slack bilge and 8 foot beam (plank-on-edge)
Boat B has a pronounced turn of the bilge and 12 foot beam

Does this change the calculation?

Todays problem
 

"KLC Lewis" wrote in message
...

"Brian Whatcott" wrote in message
...
On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Two different boats:

Boat A has a slack bilge and 8 foot beam (plank-on-edge)
Boat B has a pronounced turn of the bilge and 12 foot beam

Does this change the calculation?


Oh, and assuming identical freeboard on both vessels. Say three feet.

Todays problem
 

On Wed, 17 Dec 2008 16:25:43 -0600, "KLC Lewis"
wrote:


"Brian Whatcott" wrote in message
.. .
On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Two different boats:

Boat A has a slack bilge and 8 foot beam (plank-on-edge)
Boat B has a pronounced turn of the bilge and 12 foot beam

Does this change the calculation?

Goofball was expressing a way to account for how the hull's
roll center varies with heel. As you can see, it didn't make much
difference in his draft numbers- but it could....
Insufficient data to be definite.

BrianW

Todays problem
 

"Brian Whatcott" wrote in message
...
On Wed, 17 Dec 2008 16:25:43 -0600, "KLC Lewis"
wrote:


"Brian Whatcott" wrote in message
. ..
On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Two different boats:

Boat A has a slack bilge and 8 foot beam (plank-on-edge)
Boat B has a pronounced turn of the bilge and 12 foot beam

Does this change the calculation?

Goofball was expressing a way to account for how the hull's
roll center varies with heel. As you can see, it didn't make much
difference in his draft numbers- but it could....
Insufficient data to be definite.

BrianW


It seems to me that it should make a difference, but then again I'm an
impressionist mathematician.

Todays problem
 

Brian Whatcott wrote:
On Wed, 17 Dec 2008 18:25:22 +0000, Gordon wrote:

You have run aground. Your boat draws 6 feet when upright.
You think you can heel your boat 10 degrees by kedging with an anchor.
How much is is this going to reduce your draft?

Now, your toerail is underwater at 30 degrees of heel.
What will your draft be now?
g

6 sin 80 is about 5ft 10.8 in (heel 10 deg).
6 sin 60 is about 5. ft 2.4 in. heel 30 deg)
6 sin45 is about 4 ft 3 in (heel 45deg)

Brian W

Very good, As you can see 10 deg heel didn't give you a heck of a lot.
Gordon