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06-28-2022, 06:16 PM
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#41
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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The arms mounted
Using nylon double braid for ropes as shock absorber
Add splicing double braid to my new skills.
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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06-28-2022, 06:22 PM
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#42
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TF Site Team
City: Jacksonville
Join Date: Nov 2008
Posts: 11,683
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I like it!
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06-28-2022, 06:58 PM
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#43
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,262
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Quote:
Originally Posted by Simi 60
Revisiting this
Stainless plate has gone up drastically in price, in fact, all metals have
Be looking at near $1000 just in material for magma style for our size
Got onto a guy in Brisbane to make our arms in Aluminium and have them now
Now waiting on the bits for in the water.
Will likely be this style done using old aluminium security screen and ally box section frame
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Whitworths called me a couple of weeks ago. They finally had the Magma Rock'n'Roll come into stock. They are A$535 each.
About 6 months ago I had some lookalikes made up. Cost was $A300 for a pair, made from 1.5mm 316 SS (same as Magma). Plus some additional $ for some eye nuts, bridle and hinges. They work a treat.
Not long after installing I added a warning notice in red next to the engine start buttons as a reminder to retract them BEFORE raising anchor and cruising away. No need to ask why I decided that was a good idea......
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Brian
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06-28-2022, 07:11 PM
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#44
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Guru
City: San Diego
Vessel Name: SEA WOLF
Vessel Model: 1979 CHB 41 Trawler
Join Date: Feb 2020
Posts: 999
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Quote:
Originally Posted by Insequent
Not long after installing I added a warning notice in red next to the engine start buttons as a reminder to retract them BEFORE raising anchor and cruising away. No need to ask why I decided that was a good idea......
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Hah! Yes, I've had the same experience myself... "boy, she's sluggish this morning..."
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06-28-2022, 07:42 PM
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#45
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Quote:
Originally Posted by Insequent
Whitworths called me a couple of weeks ago. They finally had the Magma Rock'n'Roll come into stock. They are A$535 each.
About 6 months ago I had some lookalikes made up. Cost was $A300 for a pair, made from 1.5mm 316 SS (same as Magma). Plus some additional $ for some eye nuts, bridle and hinges. They work a treat.
Not long after installing I added a warning notice in red next to the engine start buttons as a reminder to retract them BEFORE raising anchor and cruising away. No need to ask why I decided that was a good idea......
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Who made those for you Brian?
Will try them myself if I may
Was told ours would need to be 3mm which seemed a tad heavy
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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06-28-2022, 07:46 PM
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#46
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,262
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Quote:
Originally Posted by Simi 60
Who made those for you Brian?
Will try them myself if I may
Was told ours would need to be 3mm which seemed a tad heavy
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I'll send a PM
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Brian
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06-28-2022, 08:04 PM
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#47
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Quote:
Originally Posted by Insequent
I'll send a PM
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And thanks
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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06-28-2022, 09:35 PM
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#48
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Member
City: Florida
Vessel Name: Sequel
Vessel Model: Endeavor 36 power cat
Join Date: Dec 2018
Posts: 15
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Roll fins
Has anyone tried roll fins? Thinking about trying them on my commercial boat. Sarted in Canada but catching on in the US.
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06-28-2022, 11:33 PM
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#49
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Guru
City: Longboat Key, FL
Vessel Name: Bucky
Vessel Model: Krogen Manatee 36 North Sea
Join Date: Oct 2009
Posts: 5,196
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Quote:
Originally Posted by Jaep
Has anyone tried roll fins? Thinking about trying them on my commercial boat. Sarted in Canada but catching on in the US.
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Interesting concept. Thanks for sharing that.
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Larry
"When life gets hard, eat marshmallows”.
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06-28-2022, 11:49 PM
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#50
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Quote:
Originally Posted by Jaep
Has anyone tried roll fins? Thinking about trying them on my commercial boat. Sarted in Canada but catching on in the US.
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Popular on steel, work a treat.
Use search on here for batwing stabilizers
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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06-29-2022, 02:52 AM
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#51
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,262
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Quote:
Originally Posted by Jaep
Has anyone tried roll fins? Thinking about trying them on my commercial boat. Sarted in Canada but catching on in the US.
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Hard to work out when the study was done, but sometime in the 2010-2015 period it seems. No doubt they are relatively cheap. It would have been better to see comparison with active fins included although I realise a lot of fishing boats would consider them too expensive.
Of course they are for stabilisation underway, whereas I started this thread specifically for stabilisation at anchor. Best to search for other stabiliser threads if you want something for when underway rather than cause thread drift here. No biggie, but I'd appreciate it ....
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Brian
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07-19-2022, 12:44 AM
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#52
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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So my improved Magma type flopper stoppers arrived yesterday
Bigger boat than magma recommended so scaled it up in size
Used 3mm 316 stainless plate
1/2 links of s/s chain welded on for attachments
Large robust 316 hinges welded on
And spent a few hours splicing the 6mm blue dyneema ropes.
The rope attaching it to the arms and arms to roof is double braid nylon, learned a new skill splicing that lot as well.
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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07-19-2022, 12:47 AM
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#53
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,262
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Looking forward to report on testing them out.
Friday night looks suitable .........
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Brian
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07-19-2022, 03:30 PM
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#54
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Guru
City: Long Beach, CA
Vessel Name: Aquarius
Vessel Model: Californian 55 CPMY
Join Date: May 2018
Posts: 725
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Quote:
Originally Posted by mvweebles
Review of the Magma Flopper Stopper.
https://setsail.com/magma-flopper-stopper-test/
My Flopper Stoppers are identical to the yellow ones in the Dashew article (they worked well for him, but based on thr test, will replace old with the Magma plates). The yellow ones work well on my boat but unfortunately are no longer made. I've considered a similar design could be inexpensively made DIY with a heavy plastic diaphragm and industrial wire mesh or expanded metal similar to these products used for safety railings and security cages;
https://www.easternmetal.com/m/stand...wire-mesh.html
Peter
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Ok, I have two of the yellow ones that the plastic is worn out, cracked and broken. I finally found a good replacement but probably not the best. It is 3/16" (2.8mm) LDPE sheet. Measuring some of the old material it seems the same only it is 1.5mm Or 0.052" thick. I have installed the 3/16 and will see how it goes. I'm on the lookout for thinner but I can't find it yet. If anyone does, please let me know. Also, as I mentioned in an earlier post the previous son of the manufacturer said the best material was rubber infused fabric. I just came up with a possibility. Old offset printing blankets. They are rubber over fabric. I'm going to check with a local printer and I know he'll give me one to try.
__________________
Aquarius 1991 Californian 55 CPMY Long Beach CA
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07-19-2022, 03:38 PM
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#55
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Guru
City: Mooloolaba
Vessel Name: Flora
Vessel Model: Timber southern cray boat
Join Date: Oct 2007
Posts: 1,859
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Quote:
Originally Posted by Simi 60
So my improved Magma type flopper stoppers arrived yesterday
Bigger boat than magma recommended so scaled it up in size
Used 3mm 316 stainless plate
1/2 links of s/s chain welded on for attachments
Large robust 316 hinges welded on
And spent a few hours splicing the 6mm blue dyneema ropes.
The rope attaching it to the arms and arms to roof is double braid nylon, learned a new skill splicing that lot as well.
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I was in the work shop the other day and saw those being fabricated. Didn't realise they were for you otherwise I would have written on them.
Waiting to hear how they go.
My magmas on Tidahapah were good once I added bit of extra weight.
__________________
"When I die I hope my wife doesn't sell my toys for what I told her I paid for them"
Money: It's made round to go round , not flat to stack.
"Get out and do it"
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07-19-2022, 05:06 PM
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#56
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Quote:
Originally Posted by Tidahapah
I was in the work shop the other day and saw those being fabricated. Didn't realise they were for you otherwise I would have written on them.
Waiting to hear how they go.
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Attachment point at roof is my concern
Every 400mm there is a 75 X 75 laminated deck beam running full width sticking out 550mm from cabin side
I chose the one on a bulkhead and also about 600 mm from a supporting upright
Drilled a 25 mm hole through the beam about 50mm from outer end, filled with epoxy glue, drilled it back out and screwed in a 12mm stainless eyebolt with backing plate.
Hoping the nylon double braid will stretch enough to take any shock loads out.
Quote:
My magmas on Tidahapah were good once I added bit of extra weight.
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These have got no shortage of weight.
Hoping I can get them out just using the trip line
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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07-23-2022, 04:16 PM
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#57
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Used them yesterday as we got a good roll up on the incoming tide against 35 knots of wind.
Pretty sure the flappy things stayed where they were and the boat still rolled but pretty sure it had slowed considerably
10mm nylon double braid has an impressive amount of stretch, I could sit in the lounge and see the tips of the arms drop a good foot and then as she rolled the other way they'd Bungy back up
Loads to the roof didn't seem to be anything to worry about so I pulled the flaps up and tied in a slightly shorter dyneema rope from roof to arm and tried again.
Rope from arm to flaps is still 10mm nylon double braid so there will be some stretch / shock absorbtion there.
Unfortunately by that stage the swell was dropping so a fair accesment can't be given yet
In a few days time well be at Peel island with ferry wash every half hour - until then...
__________________
Everything on a boat is broken, you just don't know it yet
Full time cruising is repairing boats in exotic locations
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07-24-2022, 09:44 AM
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#58
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Guru
City: Olympia
Vessel Name: Rendezvous
Vessel Model: Blue water 40
Join Date: Aug 2021
Posts: 1,815
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Quote:
Originally Posted by Simi 60
Used them yesterday as we got a good roll up on the incoming tide against 35 knots of wind.
Pretty sure the flappy things stayed where they were and the boat still rolled but pretty sure it had slowed considerably
10mm nylon double braid has an impressive amount of stretch, I could sit in the lounge and see the tips of the arms drop a good foot and then as she rolled the other way they'd Bungy back up
Loads to the roof didn't seem to be anything to worry about so I pulled the flaps up and tied in a slightly shorter dyneema rope from roof to arm and tried again.
Rope from arm to flaps is still 10mm nylon double braid so there will be some stretch / shock absorbtion there.
Unfortunately by that stage the swell was dropping so a fair accesment can't be given yet
In a few days time well be at Peel island with ferry wash every half hour - until then...
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It’s my guess that the line stretch is working against you. On the fishing boats we always used steel cable. If the line is allowed to stretch, the roll is allowed to build momentum, and the flopper is delayed.
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07-24-2022, 05:40 PM
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#59
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,262
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Quote:
Originally Posted by Bmarler
It’s my guess that the line stretch is working against you. On the fishing boats we always used steel cable. If the line is allowed to stretch, the roll is allowed to build momentum, and the flopper is delayed.
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This may well be the case. I'm using 8mm dyneema for the load lines. I'm still in the early phase of assessing them, but an effect I've noticed is outlined below.
I'm often anchored in the northern part of Moreton Bay which is traversed by ships entering the Port of Brisbane. Mostly the ships travel at 11-15 kn in the Bay with Pilots on board to meet pre-arranged times for meeting tugs or the line handling crews at their berths. But occasionally they are running late or in a hurry for some reason and barrel past my anchorage at 20 kn or so. At those times the waves from their wakes can generate enough roll in my boat to have stuff sliding across bench tops. And you know what happens - the first wave starts the roll and then more often than not the subsequent waves are in phase and exaggerate the roll. So the 3rd, 4th and 5th wave-rolls are annoying.
Since I've been using the magna-style flopper stoppers what seems to happen is the the roll amplitude is reduced a bit. I cant quantify how much but the water on the surface above the rising flopper starts to "boil" so there is clearly a decent amount of force being imparted. More importantly I suspect is that the roll period is being increased a bit. The longer roll period is enough that the 3rd and successive wave-rolls are getting more out of phase from the first couple, and the boat settles quite quickly. No more stuff sliding across the bench.
__________________
Brian
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07-25-2022, 11:27 AM
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#60
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Senior Member
City: Perth
Join Date: Jul 2014
Posts: 374
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the water on the surface above the rising flopper starts to "boil" so there is clearly a decent amount of force being imparted.
Having had a bit of experience with making and employing flopper stoppers my thoughts are -
1. Your flopper is too shallow in the water.
Or much more likely...
2. Your flopper has insufficient surface area to be effective.
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