"dry dock" in the water???
 

tomdownard wrote:
On Mar 24, 5:41 pm, wrote:

Since often (too often) boats develop problems with
an outdrive requiring the boat to be pulled, which is
often quite the pain in the ass, it seems there should
be some way of putting an enclosure around the
outdrive which is big enough to hold a person, so
it could be pumped out and someone could get in
to work on the drive. Does anyone know of such?


In Alaska we have wooden cradles or beaches that we anchor up at in
high tide.
Low tide, the boat is sitting on the hard.
We put our boots on and spread a tarp under where we are working.
We have everything ready. Parts etc. Cause we have 4 hours to get the
job done.
Then we button it up, wait for high tide, pull the hooks, and sail
away.

Cost to pull the boat....$0



What you need is a casement for a tidal driven dry-dock.
Float in, let the tide go out and close the doors.

Something like that?


--
(remove the X to email)

Now just why the HELL do I have to press 1 for English?
John Wayne

"dry dock" in the water???
 

Jere Lull wrote:


What you need is a casement for a tidal driven dry-dock. Float in, let
the tide go out and close the doors.

Something like that?


Why make it so complicated and expensive?

Just hoist the darned thing, fix the problem, then splash.

Sheesh! Sounds like a bunch of Mensans around here!



This IS a form of hauling - but could be a whole bunch cheaper
and less prone to hull damage.

Float in, settle into the slings as the water goes out.
Then close the doors for a dry place to work - until you are done.

Come to think of it, wasn't this technique used in the South Pacific
during WW-II?


Richard

--
(remove the X to email)

Now just why the HELL do I have to press 1 for English?
John Wayne

"dry dock" in the water???
 

On 2008-03-27 22:48:27 -0400, cavelamb himself said:

Jere Lull wrote:


What you need is a casement for a tidal driven dry-dock. Float in, let
the tide go out and close the doors.

Something like that?


Why make it so complicated and expensive?

Just hoist the darned thing, fix the problem, then splash.

Sheesh! Sounds like a bunch of Mensans around here!



This IS a form of hauling - but could be a whole bunch cheaper and less
prone to hull damage.

Float in, settle into the slings as the water goes out. Then close the
doors for a dry place to work - until you are done.

Come to think of it, wasn't this technique used in the South Pacific
during WW-II?

We're talking CRUISING boats, in the current world, without the benefit
of a military budget. Large tidal differences exist, but are not the
norm in the real world of cruising.

Haul, fix, splash is the current state of the art for most cruising
boats. Technology has marched on in the past 50-60 years. Travel lifts
are now the norm.

(and we have a marine railway and other last-generation technologies
within our normal weekend range. We choose current technology.)

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

"dry dock" in the water???
 

On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:

On 2008-03-27 22:48:27 -0400, cavelamb himself said:

Jere Lull wrote:


What you need is a casement for a tidal driven dry-dock. Float in, let
the tide go out and close the doors.

Something like that?


Why make it so complicated and expensive?

Just hoist the darned thing, fix the problem, then splash.

Sheesh! Sounds like a bunch of Mensans around here!



This IS a form of hauling - but could be a whole bunch cheaper and less
prone to hull damage.

Float in, settle into the slings as the water goes out. Then close the
doors for a dry place to work - until you are done.

Come to think of it, wasn't this technique used in the South Pacific
during WW-II?

We're talking CRUISING boats, in the current world, without the benefit
of a military budget. Large tidal differences exist, but are not the
norm in the real world of cruising.

Haul, fix, splash is the current state of the art for most cruising
boats. Technology has marched on in the past 50-60 years. Travel lifts
are now the norm.

(and we have a marine railway and other last-generation technologies
within our normal weekend range. We choose current technology.)


Over in the Philippines I saw a floating dry dock made of plywood. It
was essentially a barge with a cradle on it. They sank it in shallow
water, loaded the boat and blew the water out of the pontoons with a
compressor to refloat the thing. Home made rig, but worked.

The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.


Bruce-in-Bangkok
(correct email address for reply)

"dry dock" in the water???
 

"Bruce in Bangkok" wrote in message
...
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:
The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.

There is some logical use for such a device if you plan to do some major
work which you might not be able to finish on one low water session.

"dry dock" in the water???
 

On Sat, 29 Mar 2008 17:06:05 +0100, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
.. .
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:
The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.

There is some logical use for such a device if you plan to do some major
work which you might not be able to finish on one low water session.


Look, if you are going to hang a boat in a sling then(1) you use a
travel lift or crane device and pick it up, or (2) you position the
slings and float the boat into them at high tide and when the tide
goes down you can work on it.

However using method (2) every high tide the boat has sufficient water
around it to float it. so why not just put it on the beach? Lash legs
in place and you have exactly the same situation - at high tide the
water covers everything up to the water line.

The slings also have the disadvantage of being rather costly. Have you
prices 15,000 lb. capacity slings recently? Better yet price 17,000
lb. slings, I want a bit of a safety factor on this project. Another
problem is what are you going to tie the slings to? Have you got a
couple of strategically located trees available? Or are you going to
build something?

Bruce-in-Bangkok
(correct email address for reply)

"dry dock" in the water???
 

"Bruce in Bangkok" wrote in message
...
On Sat, 29 Mar 2008 17:06:05 +0100, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
. ..
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:
The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.

There is some logical use for such a device if you plan to do some major
work which you might not be able to finish on one low water session.


Look, if you are going to hang a boat in a sling then(1) you use a
travel lift or crane device and pick it up, or (2) you position the
slings and float the boat into them at high tide and when the tide
goes down you can work on it.

However using method (2) every high tide the boat has sufficient water
around it to float it. so why not just put it on the beach? Lash legs
in place and you have exactly the same situation - at high tide the
water covers everything up to the water line.

The slings also have the disadvantage of being rather costly. Have you
prices 15,000 lb. capacity slings recently? Better yet price 17,000
lb. slings, I want a bit of a safety factor on this project. Another
problem is what are you going to tie the slings to? Have you got a
couple of strategically located trees available? Or are you going to
build something?

Bruce-in-Bangkok
(correct email address for reply)

No, sorry,I did not make my scheme clear.
My idea was for a floating dock supported by air tanks so it could float
with a yacht in it.
Position the empty dock over the beach and flood the tanks so it sinks.
Side supports stick up above water so you can correctly position the yacht
above it.
Next low water the yacht will be sitting on it and you close the valves on
the tanks so the whole issue floats on the next tide and continues to float
the yacht on every tide until the job is finished.
Then you flood the tanks again and the yacht sails away.
You could build a thing like that comparitively cheaply as there is nothing
mechanical on it at all.

"dry dock" in the water???
 

On Sun, 30 Mar 2008 10:34:40 +0200, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
.. .
On Sat, 29 Mar 2008 17:06:05 +0100, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
...
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:
The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.

There is some logical use for such a device if you plan to do some major
work which you might not be able to finish on one low water session.


Look, if you are going to hang a boat in a sling then(1) you use a
travel lift or crane device and pick it up, or (2) you position the
slings and float the boat into them at high tide and when the tide
goes down you can work on it.

However using method (2) every high tide the boat has sufficient water
around it to float it. so why not just put it on the beach? Lash legs
in place and you have exactly the same situation - at high tide the
water covers everything up to the water line.

The slings also have the disadvantage of being rather costly. Have you
prices 15,000 lb. capacity slings recently? Better yet price 17,000
lb. slings, I want a bit of a safety factor on this project. Another
problem is what are you going to tie the slings to? Have you got a
couple of strategically located trees available? Or are you going to
build something?

Bruce-in-Bangkok
(correct email address for reply)

No, sorry,I did not make my scheme clear.
My idea was for a floating dock supported by air tanks so it could float
with a yacht in it.
Position the empty dock over the beach and flood the tanks so it sinks.
Side supports stick up above water so you can correctly position the yacht
above it.
Next low water the yacht will be sitting on it and you close the valves on
the tanks so the whole issue floats on the next tide and continues to float
the yacht on every tide until the job is finished.
Then you flood the tanks again and the yacht sails away.
You could build a thing like that comparitively cheaply as there is nothing
mechanical on it at all.

You are talking about fairly significant tides. If, at low water you
have the dock situated on the beach just above the tide line (you need
it above the tide line as you are going to drain all the water out of
the tanks at the next low water) you are going to have a device that
is two or three feet thick, say 3 feet. So, to get sufficient water
over it to load my boat you are going to need in excess of 9 foot
tides, say 10 foot tides.

Next, this is not going to be some little dinky device. You are
talking about a 40 ft. boat with a breadth of, say 12 feet, and a
draft of 6 feet. Your tanks and cradle is going to be a fairly
significant structure and of course you are going to get caught in a
trap. Every time you make it bigger or stronger it becomes heavier and
thus needs larger tanks to float it and that makes it heavier and it
needs to stronger and that takes more tanks that make it
heavier...........

Another point is that a certain number of modern, bolt on keel, boats
won't stand on their keel so you need an even more substantial cradle.

Basically what you are talking about is called a floating dry dock and
is in fairly common use, except that you aren't pumping the tanks so
it will only work in areas with fairly big tides.

I still think it is a bad idea. Redesign it to pump the tanks with an
air compressor (remember to do all this heavy maintenance you are
going to need a generator to furnish electrical power so why not an
air compressor) and make it into a real floating dry dock and it will
be rather more useful.

Bruce-in-Bangkok
(correct email address for reply)

"dry dock" in the water???
 

This crazy...........a three day haul in NY costs a couple of hundred
dollars. It take 30 minutes for the boat to go from floating to blocked. Its
on dry land the entire time and can be replaced in the water at any time.
Your truck can be a few steps away electric and water is often included. Why
do people always try to reinvent the wheel??

John



"Bruce in Bangkok" wrote in message
...
On Sun, 30 Mar 2008 10:34:40 +0200, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
. ..
On Sat, 29 Mar 2008 17:06:05 +0100, "Edgar"
wrote:


"Bruce in Bangkok" wrote in message
m...
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:
The tide and sling rig isn't logical and I can't believe ever
existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.

There is some logical use for such a device if you plan to do some major
work which you might not be able to finish on one low water session.


Look, if you are going to hang a boat in a sling then(1) you use a
travel lift or crane device and pick it up, or (2) you position the
slings and float the boat into them at high tide and when the tide
goes down you can work on it.

However using method (2) every high tide the boat has sufficient water
around it to float it. so why not just put it on the beach? Lash legs
in place and you have exactly the same situation - at high tide the
water covers everything up to the water line.

The slings also have the disadvantage of being rather costly. Have you
prices 15,000 lb. capacity slings recently? Better yet price 17,000
lb. slings, I want a bit of a safety factor on this project. Another
problem is what are you going to tie the slings to? Have you got a
couple of strategically located trees available? Or are you going to
build something?

Bruce-in-Bangkok
(correct email address for reply)

No, sorry,I did not make my scheme clear.
My idea was for a floating dock supported by air tanks so it could float
with a yacht in it.
Position the empty dock over the beach and flood the tanks so it sinks.
Side supports stick up above water so you can correctly position the yacht
above it.
Next low water the yacht will be sitting on it and you close the valves on
the tanks so the whole issue floats on the next tide and continues to
float
the yacht on every tide until the job is finished.
Then you flood the tanks again and the yacht sails away.
You could build a thing like that comparitively cheaply as there is
nothing
mechanical on it at all.

You are talking about fairly significant tides. If, at low water you
have the dock situated on the beach just above the tide line (you need
it above the tide line as you are going to drain all the water out of
the tanks at the next low water) you are going to have a device that
is two or three feet thick, say 3 feet. So, to get sufficient water
over it to load my boat you are going to need in excess of 9 foot
tides, say 10 foot tides.

Next, this is not going to be some little dinky device. You are
talking about a 40 ft. boat with a breadth of, say 12 feet, and a
draft of 6 feet. Your tanks and cradle is going to be a fairly
significant structure and of course you are going to get caught in a
trap. Every time you make it bigger or stronger it becomes heavier and
thus needs larger tanks to float it and that makes it heavier and it
needs to stronger and that takes more tanks that make it
heavier...........

Another point is that a certain number of modern, bolt on keel, boats
won't stand on their keel so you need an even more substantial cradle.

Basically what you are talking about is called a floating dry dock and
is in fairly common use, except that you aren't pumping the tanks so
it will only work in areas with fairly big tides.

I still think it is a bad idea. Redesign it to pump the tanks with an
air compressor (remember to do all this heavy maintenance you are
going to need a generator to furnish electrical power so why not an
air compressor) and make it into a real floating dry dock and it will
be rather more useful.

Bruce-in-Bangkok
(correct email address for reply)

"dry dock" in the water???
 

On Sun, 30 Mar 2008 16:55:10 +0700, Bruce in Bangkok
wrote:

snippage

Basically what you are talking about is called a floating dry dock and
is in fairly common use, except that you aren't pumping the tanks so
it will only work in areas with fairly big tides.

I still think it is a bad idea. Redesign it to pump the tanks with an
air compressor (remember to do all this heavy maintenance you are
going to need a generator to furnish electrical power so why not an
air compressor) and make it into a real floating dry dock and it will
be rather more useful.

Bruce-in-Bangkok
(correct email address for reply)

My yacht club has a variation on the floating drydock concept that we
call a "lifter". The lifter floats are never flooded - instead, a
platform between the floats is raised an lowered using an electric
winch. When lowered, the boat can be driven onto the platform, then
the platform is raised to allow work on the boat.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca