beryl george wrote:

From other members of the news group thoughts and
experience am I missing something or is this something
that can be carried out providing there is care with
a reasonable degree of ease and safety.

The plan is to block of the foot of the keel and
secure ropes from the top of the mast out to the
sides at about 45 degrees to hold the boat upright
so the support pads on the wintering cradle can be
lowered

Well, provided you have something very secure to anchor the far end of
the ropes to, that would work fine.

But you could shortcut the procedure and not take up nearly so much room
by using some "legs" which could be simple stout poles, or something a
bit more complex, secured to the boat's chainplates. That's what holds
the mast up, so you'd be using the same part of the hull which is built
ver very strongly... but you'd be saving all the stress on the rig.

Fresh Breezes- Doug King

beryl george wrote:

To what do you propose to tie the other ends of the ropes?

To the cradles of surrounding boats.

I would not be happy to have you as a neighbor in this instance. Aside from
the fact that I am just being a grump, this is very poor practice. In the
second (or third, or whatever) place, you must somehow assure your
neighbors, the yard, and the insurance companies that this is a good idea.

Which it definitely is not.

--
Good luck and good sailing.
s/v Kerry Deare of Barnegat
http://kerrydeare.home.comcast.net/

beryl george wrote:

To what do you propose to tie the other ends of the ropes?

To the cradles of surrounding boats.

I would not be happy to have you as a neighbor in this instance. Aside from
the fact that I am just being a grump, this is very poor practice. In the
second (or third, or whatever) place, you must somehow assure your
neighbors, the yard, and the insurance companies that this is a good idea.

Which it definitely is not.

--
Good luck and good sailing.
s/v Kerry Deare of Barnegat
http://kerrydeare.home.comcast.net/

If this is an attached fin keel then I would be more concerned with the long
term effect of the compression load where the keel is attached..

Say the ballast only accounts for 4 to 6 tons, the remainder of the 10 ton
will be concentrated on the faying surface between the keel and the hull..
This could ultimately cause damage to the internal keels support
structures..

I recommend you consult the boat designer or builder or a competent naval
architect..

Again, I find not fault in holding the boat upright with the mast but this
provides not under hull support.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

If this is an attached fin keel then I would be more concerned with the long
term effect of the compression load where the keel is attached..

Say the ballast only accounts for 4 to 6 tons, the remainder of the 10 ton
will be concentrated on the faying surface between the keel and the hull..
This could ultimately cause damage to the internal keels support
structures..

I recommend you consult the boat designer or builder or a competent naval
architect..

Again, I find not fault in holding the boat upright with the mast but this
provides not under hull support.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

On Fri, 05 Mar 2004 20:47:21 +0000, beryl george
wrote:



To what do you propose to tie the other ends of the ropes?

snip

To the cradles of surrounding boats.

Definitely don't do that. There should be nothing tied to the cradles.

Steve

On Fri, 05 Mar 2004 20:47:21 +0000, beryl george
wrote:



To what do you propose to tie the other ends of the ropes?

snip

To the cradles of surrounding boats.

Definitely don't do that. There should be nothing tied to the cradles.

Steve

beryl george wrote:

Wouldn't it be simpler just to run ropes from the bottom
corners of the cradle frame to strong points on deck?

Would not rope stretch be a possible potential problem with
such a heavy boat.

Not really, but you could use chain instead if it worries you.

Just roughly: Suppose your mast ropes are at 45 degrees, the
deck is 10ft above ground, the mast is 50ft tall, then the
mast ropes will be 85ft long.

Suppose a lateral force is applied (by wind, say) which is enough
to tilt the boat by 5 degrees against the tension of the mast
rope. That would cause the mast rope to stretch by 3.5 feet, or
about 4% of its length.

If your half-beam is 7ft, and the cradle bottom half-beam is
the same, I calculate the cradle rope would need to stretch from
10ft to 10.6 ft, or 6% of its length, in order to permit the
same 5 degree angle of heel.

Now if you were using the same type of rope for cradle-to-deck
as for elsewhere-to-mast, and if both ropes may be presumed to
be operating within their linear stretch/tension range, then it
takes 1.5 times as much force to stretch it by 6% as by 4%. The
lever arm advantage follows from the stretch distance ratios,
3.5:0.6, or about 5.8:1. This means that a heeling moment which
exerts 1 unit of tension on the mast rope would exert 5.8 units on
a cradle rope. Divide this by the force ratio of 1.5 to get a
number a little less than 4. I reckon that means you're as OK
if you use 4 cradle ropes each side as you would be if using one
mast rope of the same calibre and stretchiness each side.

Better still if you use heavier and/or less stretchy rope.

beryl george wrote:

Wouldn't it be simpler just to run ropes from the bottom
corners of the cradle frame to strong points on deck?

Would not rope stretch be a possible potential problem with
such a heavy boat.

Not really, but you could use chain instead if it worries you.

Just roughly: Suppose your mast ropes are at 45 degrees, the
deck is 10ft above ground, the mast is 50ft tall, then the
mast ropes will be 85ft long.

Suppose a lateral force is applied (by wind, say) which is enough
to tilt the boat by 5 degrees against the tension of the mast
rope. That would cause the mast rope to stretch by 3.5 feet, or
about 4% of its length.

If your half-beam is 7ft, and the cradle bottom half-beam is
the same, I calculate the cradle rope would need to stretch from
10ft to 10.6 ft, or 6% of its length, in order to permit the
same 5 degree angle of heel.

Now if you were using the same type of rope for cradle-to-deck
as for elsewhere-to-mast, and if both ropes may be presumed to
be operating within their linear stretch/tension range, then it
takes 1.5 times as much force to stretch it by 6% as by 4%. The
lever arm advantage follows from the stretch distance ratios,
3.5:0.6, or about 5.8:1. This means that a heeling moment which
exerts 1 unit of tension on the mast rope would exert 5.8 units on
a cradle rope. Divide this by the force ratio of 1.5 to get a
number a little less than 4. I reckon that means you're as OK
if you use 4 cradle ropes each side as you would be if using one
mast rope of the same calibre and stretchiness each side.

Better still if you use heavier and/or less stretchy rope.

"beryl george" wrote in message
...

The boat weight is around 10 ton with a 50 foot
plus mast and a moderate keel that is level bottom.

All thoughts very much appreciated I have not seen
or done or attempted any thing like this before.


Sounds like extreme folly to me. The mast will bend, the lines will stretch,
the boat will teeter and tip one way or another. Then anything might happen.
And you are going to do this in among a lot of other boats? Think long and
hard about the consequnces of it falling over, then ask yourself how you
could ever have thought it was a good idea.

Tim W