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Old 01 April 2005, 10:52   #11
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For those who are interested new "Hi Tech" ropes come in super strength for their size - 3mm dynema is stronger than 3mm stainless wire - how flash would you look hoisting your RIB on that?
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Old 01 April 2005, 11:02   #12
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It looks like you're specifying the lifting strops with plenty of strength, but bear in mind that their length, and hence the angle at which they are used, will determine the actual loading on each strop.

In general terms, the shorter the strop, then the greater the angle from the vertical, and the resultant force will be greater.

For a longer strop with the same boat weight, then the smaller the angle to the vertical, and the resultant force will be less (ie closer to the supported weight).

This vector diagram shows that if you rig the strops at 45 then the resultant force is 1.414 times the boat mass supported by each one (ie a four tonne boat, evenly distributed, places a force of 1,414 kgf on each strop.
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Old 01 April 2005, 13:41   #13
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Quote:
Originally Posted by dctucker

Sling,Web,Light Duty
Light Duty Web Sling, Width 1 Inch, Sling Type Eye and Eye, Vertical Load Capacity 2400 Pounds, Basket Hitch Capacity 4800 Pounds, Choker Hitch Capacity 1900 Pounds, Overall Length 6 Feet, Double Ply, Nylon, Flat Eye
The 6 footers that you've outlined here aren't going to be of any use for you're application as they'd never reach a central point for lifting, I would suggest the same load capacity but use 5 or 6 meter ones. 3 Strops are Ideal as when you lift your boat you will find each strop is carrying a roughly equal load. The mention of 4 strops are for peeps that slinge the boat right underneath the "basket hitch method".
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Old 02 April 2005, 05:53   #14
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We use 3 X 5metre strops to lift our race boat - it weighs about 1000kg with full fuel - does anyone have a good supplier of strops at a reasonable price - must have a certificate for racing!
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When a boat looks that good who needs tubes!!!
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Old 05 April 2005, 10:49   #15
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The official word from Avon

Here's my correspondence with with Avon, and the official word:

I recently purchased an ex-military Searider 5.4, equipt for 3 point lift. I plan on using a 2 tonne hoist to lift the boat in and out of the water. It is fitted with a 2 stroke 80 hp outboard and can carry 25 gallons of fuel. Can you advise me of the legnth and load capacity required for lifting staps for this boat?

Thank You,

DanTucker


Thanks for your e-mail.

Our first recommendation is that you purchase an Avon sling for your boat. Info on pricing and availability can be obtained from ZNA Inc. in Stevensville. Contact Name Tim Franks, e-mail address: TFrank@zna.zodiac.com

Failing that, if you get a sling fabricated (at your own risk and responsibility) the 3 leg lengths should be as follows:
Forward leg - 109.5 inches.
Stern legs - 84.25 inches.
The sling should be constructed to have a Safe Working Load of 1.5 ton. and a Proof load of 3.0 ton
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Old 05 April 2005, 17:13   #16
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should we put that reply in our reference sekshun!
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Old 15 April 2005, 08:19   #17
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The searider 5.4 water ballast holds about 167 litres
regards
richard
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Old 15 April 2005, 10:30   #18
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Quote:
Originally Posted by richard m
The searider 5.4 water ballast holds about 167 litres
regards
richard
Thank you!

Forgive my fogginess on metric measure, but 1 litre = 1 kg, correct?

I pulled out a copy of Chapman's last night and reminded myself how to do an eye splice. I'm just going to by some 5/8" 3 strand nylon line with a break stregnth of 10,000+ lbs and splice up my own lines. Cost will be a whopping $20 USD.
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Old 15 April 2005, 10:33   #19
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Quote:
Originally Posted by dctucker
Thank you!

Forgive my fogginess on metric measure, but 1 litre = 1 kg, correct?
More or less, Des
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Old 16 April 2005, 09:21   #20
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Yes you are correct 1litre =1 kg of fresh water.
I used to have a 5.4m searider ,one day while the boat was on the trailer,jacked up at the front. I pluged up the transom ballast hole and filled the ballast from the front hole and measured the water I put in.
I should never had sold my searider it was a great boat!
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richard m
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