Off the wall question: Underwater plumb bob?
 

I kinda like the trailer knobs and adjustable fishing bobbers. I have
accumulated several GPS units so getting back to the same general place
will not be a problem but these test have gotten a bit more complicated
than I first thought. last time we just duplicated the Practical Sailor
tests and got pretty much the same results. This time I want to measure
creep under loads 10-15% below where they drag, how far they sail from
the drop point and get more accurate mesurements on how far they take to
set. A lot of that requires mesurements in inches.

All this may seem a bit over the top but if I am selling these things I
want to know everything about them. Besides, I made a little profit on
the anchors last year and need to be able to show the tax man that 10
days in the BVI is a legitimate business expense. ;-)

Lew Hodgett wrote:
"Glenn Ashmore" writes:


Anyone ever seen such a device or have a better idea?


IMHO, you can't get there from here with what you are considering.

Your friend will be a high speed, hand held GPS.

You won't get it for $100, but it will do the job.



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 21:25:57 -0400, Glenn Ashmore
wrote:
Ever try to pack a concrete block? :-) I need something that will drop
straight and fast and most of all I can pack without adding much weight.
I am already carrying 110 pounds of anchors and need a little room for
a bathing suit and a toothbrush, :-)

===========================================

Hmmmm. You might get better luggage/volumetric efficiency with a
brick or a lead fishing sinker. You need some weight on the bottom
however to get it to stay put. Another possibility is to use a small
danforth type, set it firmly, and then shorten the scope to vertical
attached to a small float like a seat cushion.

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 21:25:57 -0400, Glenn Ashmore
wrote:
Ever try to pack a concrete block? :-) I need something that will drop
straight and fast and most of all I can pack without adding much weight.
I am already carrying 110 pounds of anchors and need a little room for
a bathing suit and a toothbrush, :-)

===========================================

Hmmmm. You might get better luggage/volumetric efficiency with a
brick or a lead fishing sinker. You need some weight on the bottom
however to get it to stay put. Another possibility is to use a small
danforth type, set it firmly, and then shorten the scope to vertical
attached to a small float like a seat cushion.

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 23:08:14 -0400, Glenn Ashmore
wrote:
Besides, I made a little profit on
the anchors last year and need to be able to show the tax man that 10
days in the BVI is a legitimate business expense. ;-)

=============================================

I suspected something like that but restrained myself from comment
:-}

For those who don't know, Glenn is selling these anchors at pretty
fair prices. I bought a 44 pounder from him 2 years ago and regard it
as the best all around anchor I've used in 40 years of boating. If I
get the Grand Banks 49 that we're contemplating, I'll probably spring
for a new 66 pounder as the primary anchor.

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 23:08:14 -0400, Glenn Ashmore
wrote:
Besides, I made a little profit on
the anchors last year and need to be able to show the tax man that 10
days in the BVI is a legitimate business expense. ;-)

=============================================

I suspected something like that but restrained myself from comment
:-}

For those who don't know, Glenn is selling these anchors at pretty
fair prices. I bought a 44 pounder from him 2 years ago and regard it
as the best all around anchor I've used in 40 years of boating. If I
get the Grand Banks 49 that we're contemplating, I'll probably spring
for a new 66 pounder as the primary anchor.

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 23:08:14 -0400, in message
UeFjc.673$Lm3.174@lakeread04
Glenn Ashmore wrote:

This time I want to measure
creep under loads 10-15% below where they drag, how far they sail from
the drop point and get more accurate mesurements on how far they take to
set. A lot of that requires mesurements in inches.

You may want to re-evaluate how your measurements will be used. I
can't think of an anchoring situation where differences in past
performance data measured in inches would affect my decision.

As for providing a solid reference point, it seems you don't care
exactly where your reference is, just that it should stay where it's
put. Drop one of the anchors you aren't in the process of testing with
the fishing bobber attached, then make your reference point wherever
it happens to land.

Ryk

Off the wall question: Underwater plumb bob?
 

On Tue, 27 Apr 2004 23:08:14 -0400, in message
UeFjc.673$Lm3.174@lakeread04
Glenn Ashmore wrote:

This time I want to measure
creep under loads 10-15% below where they drag, how far they sail from
the drop point and get more accurate mesurements on how far they take to
set. A lot of that requires mesurements in inches.

You may want to re-evaluate how your measurements will be used. I
can't think of an anchoring situation where differences in past
performance data measured in inches would affect my decision.

As for providing a solid reference point, it seems you don't care
exactly where your reference is, just that it should stay where it's
put. Drop one of the anchors you aren't in the process of testing with
the fishing bobber attached, then make your reference point wherever
it happens to land.

Ryk

Off the wall question: Underwater plumb bob?
 

You might want to look into the SI-701WPBI from Columbia Research
Laboratories, Inc at:

http://www.columbiaresearchlab.com/

Look under Inclinometers. There is a PDF file available with the specs. It
might be what you are looking for.

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
victorf ATSIGN windreader DOTcom
KC2GUI

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

"Wayne.B" wrote in message
...
| On Tue, 27 Apr 2004 21:25:57 -0400, Glenn Ashmore
| wrote:
| Ever try to pack a concrete block? :-) I need something that will drop
| straight and fast and most of all I can pack without adding much weight.
| I am already carrying 110 pounds of anchors and need a little room for
| a bathing suit and a toothbrush, :-)
|
| ===========================================
|
| Hmmmm. You might get better luggage/volumetric efficiency with a
| brick or a lead fishing sinker. You need some weight on the bottom
| however to get it to stay put. Another possibility is to use a small
| danforth type, set it firmly, and then shorten the scope to vertical
| attached to a small float like a seat cushion.
|
|
|

Off the wall question: Underwater plumb bob?
 

You might want to look into the SI-701WPBI from Columbia Research
Laboratories, Inc at:

http://www.columbiaresearchlab.com/

Look under Inclinometers. There is a PDF file available with the specs. It
might be what you are looking for.

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
victorf ATSIGN windreader DOTcom
KC2GUI

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

"Wayne.B" wrote in message
...
| On Tue, 27 Apr 2004 21:25:57 -0400, Glenn Ashmore
| wrote:
| Ever try to pack a concrete block? :-) I need something that will drop
| straight and fast and most of all I can pack without adding much weight.
| I am already carrying 110 pounds of anchors and need a little room for
| a bathing suit and a toothbrush, :-)
|
| ===========================================
|
| Hmmmm. You might get better luggage/volumetric efficiency with a
| brick or a lead fishing sinker. You need some weight on the bottom
| however to get it to stay put. Another possibility is to use a small
| danforth type, set it firmly, and then shorten the scope to vertical
| attached to a small float like a seat cushion.
|
|
|

Off the wall question: Underwater plumb bob?
 

"Glenn Ashmore" wrote in message
news:lszjc.337$Lm3.227@lakeread04...

To measure the set distance I need some means of
marking exactly the location that the anchor was dropped. I am
invisioning some sort of pointed weight with a boyant shaft that can be
dropped as the anchor is released.

One of the problems that you may have is getting your marker weight to drop
straight down. A weight that has any flat surfaces can angle through the
water and land a fair distance from the point you dropped it. A recommend a
bullet shaped diving weight. The same is true for the anchor you are
testing, unless you lower it slowly it can veer off some amount as well.
Unless you can hold your position accurately long enough to drop two things
slowly you will always have a problem

The best solution would be to use a diver to mark the spot underwater. Get
the diver out of the way, drop the anchor, then have the diver come set a
marker next to the anchor. Do your set/drag test then have the diver
measure the distance along the bottom. That will assure that current, wind
and drop issues are not a factor.

If you can't do that, then I would recommend attaching a marker float to the
anchor. Use a light weight line attached to a spot on the anchor where it
would interfere. Drop the anchor and a second marker float. Once things
have settled measure the distance between the anchor float and the secondary
marker float. Set the anchor, and measure again. The difference between
the first and second measurements is how much the anchor moved. Since both
floats are subject to the same current and wind the effects should cancel.

For the floats themselves, I would recommend a pulley system. The rope
comes up from the bottom and passes through a small pulley on the bottom of
the float and then attaches to another weight. This allows the float to
automatically adjust for water depth and keeps the scope to an absolute
minimum.

Rod