500-700 LB. Spring Type Scales...Need Source

It's not a dumb question, two scales in series (in-line) will do as long as they are identical. The load should simply register half on each scale, so two 350 kg scales would register 250 kg each if the load were 500 kg total.

Two in parallel, surely?

'One in parallel' is enough.

Put a pulley on the transom, one line through it, & its' two ends back to load. Put scale in one of the two lines, near the transom.

Double the reading.

Isn't it better to parallel the scales rather than in series? Like putting one scale at the head end and another scale at the tail end, then adding the registered weight on both scales.. Since the total weight will be distributed between the two scales in this manner..

Don't know? I will probably try different set ups when we get out there.

Thank you for the comment.

How about a hydraulic scale...?

http://www.northerntool.com/shop/tools/product_7185_7185

EAGLE,

This would work. I will contact them on Monday. Problem is time frame and will it take getting wet.....like getting dunked every so often. I need to ship everything out on Wednesday. New gear, never been tested....small boat ( 20')...small winch ( 2000 lb. cap....I start out with safety first. I do not want more than 600lbs on the towline or I will have them find a bigger hull.

Chasing SnakeHeads...nasty mouth full of teeth, eat everything and anything that moves...... and should NOT be where they are .... which is Central Arkansas.

Thank you for the heads up.

For a backup I will still go with the tandem scales IN CASE this hydraulic scale does not pan out.

Thank you for finding this.

Yes a very angry looking fish that, as I understand, can walk across land....

Yes the Sherline mod# LM2-2000 sounds perfect, although the glass(?) front on the gauge seems vulnerable...maybe a protective foam rubber wrap around the gauge might help....I don't see anything about waterproof, but does seem to be well made and is industrial use design...I found a listing on Amazon who can ship quickly, but it costs....

http://www.amazon.com/Sherline-Products-Suspended-Hydraulic-Scale/dp/B0000AX78B

http://www.sherline.com/lm2.htm

Eagle,

Thank you again.

Actually the fish lay on their belly when they wind up on the bank. they wiggle and wiggle all over, maybe going a few feet .

However, if they have just 1" of water , like a run off or puddle, they haul @$$ at full throttle with those rounded Caudal tails.

I'll look at this too. I am not sure how much these guys are willing to put out. If we were on a larger boat, I'd use one the "S shaped electronic cells...but we will be out in the Boonies and its all hand power. ha ha !

The hydraulic version also lends itself to remotely mounting the pressure gauge.

Fabricate and install a suitable length of hydraulic hose between the load cell and where you want the gauge.

The gauge face can then be both mechanically protected and easy to read from anywhere on the boat that the hose is made to reach.

You must be makin' one heck of a longbow

Del

LIKE THIS?

Can't do a drawing now, but imagine an long isosceles triangle - long arms chain, with spring balance in one of them. Base - solid bar with hole at mid-point. Attach vertex (pointy bit) to boat, and gear to mid-point of base bar. Hope this makes sense.

I am afraid that having a steel bar on this light rig will make it more difficult for hauling and deploying. They have to work all the gear over the side and just use the winch to get it near the boat. If successful, then they will build a boat capable of handling everything needed....but for now its all Prototype and R&D.

I may not be understanding your explanation though.

That's it - but only need one scale - the tension is the same in each arm (provided the spring extension is fairly small relative to the other dimensions).

Where would the scale be placed? Along the single end going to the boat?

Will this handle the required 500lbs.>600lbs. of Bollard Pull?

What is the SHORTEST lengths of chain I could get away with?

What is the SHORTEST Beam I could use?

Can I get away with using a DOUBLE tow points or does it have to be a single?

The tow points, with a short beam might be handle-able in a small boat.

The double would be more stable as there are 2 tow lines, which can be spliced into a "V" shaped bridle if necessary. But two separate ones are the best.

Thank you.

The spring must be in one of the two equal legs of the triangle - and Wal's right, the tension in each leg will be more than half the total; but the error will be small provided that the two long legs are at least 5 x the length of the bar. The tow must be single point, at the mid-point of the bar.

That's a good enough work around.

Second thought....How long does that beam have to be?

.5 Meter

1 meter

2 Meters

etc.

Sort of, but the beam can be shorter.

Will this configuration work. For our work , ease of handling and stability with the gear going in and out of the boat....its is the simplest......BUT WILL THIS WORK?

Yes.

One 350 is enough - get a 6' beam, horizontal, scale at one end, pivot on other end.

Zero scale, put load in middle. Double the reading on the scale.

Accuracy nearly the same, depends on 'middle' and 'horizontal'.

Here is my problem with the Beam /Scale/Balance

I need the scale to be within a read-able distance of the boat.

This single-Balance/Beam is a truly neat looking idea but at 5x's the length, I am afraid we will NOT be able to read the scale or be able to disengage it to wind up everything on the winch. We are working with 4 men in a boat, possibly as little as a 6x5 working area, boat moving at 2-3 knots, current pushing boat ( some rocking).Gantry with the snatch block just 5-6' over head. Single drum winch.

Cramped area and a not-so-steady working platform.

Suggestions?

Doesn't help for winching it aboard (in fact probably makes it worse), but the spring balance must be in the triangle, eg:

try these folks.They make 500lb+ linear mechanical scales. I saw one on a charter fishing boat (halibut)

http://www.chatillon-scales.com/products/hanging-scales/mechanical-hanging-scales/IronClad-Straight-Linear-Scales.aspx

this is the one I saw on the boat:

Have you considered one of these?

IP66 rating should be OK if it's on the towing cleat on board your boat.

That is the first time I ever saw something like that. Its worth a call for sure.

thank you.

From the link:

GENERAL SPECIFICATIONS

• Ranges 12tonne to 35tonne

Maybe a bit OTT? Can't find anything about resolution or accuracy.

I was wondering about that too. Same as you I couldn't find anything on resolution or accuracy...probably need to contact them to be sure.

Even 10kg accuracy/display resolution would be enough for Netmaker's application and I wouldn't be surprised if it can go to 1 or even 0.25kg. It's just a nicely packaged strain gauge when you get down to it.

It couldn't be worse than the approximate solutions proffered so far.

Simplicity and ease of deployment seems to be important here.

Yes, that will be over kill..... neat looking device though.

Just get a Dillon AP series dynamometer. Not real expensive and available in any range you need. Hook it up and measure.

I've used these to correctly tension/validate the guy ropes on guyed mast towers.

Guy ropes don't jiggle around much, I'm not sure how these would perform with dynamic loads though.