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PostPosted: Fri Jan 29, 2010 8:41 pm 
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Joined: Thu May 17, 2007 4:43 am
Posts: 130
Location: Seal Beach California
Has any one developed a system to fair the plug better with the hull to reduce drag I recon RR has done this just cannot find the post
Thanks,
Mike


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PostPosted: Mon Feb 01, 2010 1:56 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2866
Location: Central Coast NSW Australia
MRL,
Roadrunner uses packing tape for streamlining the hull:
viewtopic.php?f=11&t=11072&p=58678
viewtopic.php?f=69&t=10591&p=55598
viewtopic.php?f=11&t=9232&p=47448


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PostPosted: Wed Feb 03, 2010 9:44 pm 
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Joined: Thu May 17, 2007 4:43 am
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Location: Seal Beach California
Thanks much I think I will go with the molded plug


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PostPosted: Tue May 11, 2010 4:06 pm 
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Joined: Sat Oct 24, 2009 10:33 am
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Haven't actually tested this yet, but here's what I came up with. It's cheap, easy, and looks good, anyway.

My plug seems to sit in the hole in one of two "modes." When I first insert it, one end sticks up a bit and the other end sits down on the end tab. In this "mode" the bottom of the plug isn't parallel with the bottom of the boat. If you shove down on the high end, the plug snaps into the other "mode," in which the bottom of the plug hovers ~1/4 inch (~6mm) above the keel line.

So it occurred to me that a ~1/4-in.-thick layer of some kind of foam glued to the bottom of the plug, and (unlike the plug) actually shaped like the hole, would do a good job of fairing. The only problem being I didn't know how to get my hands on 1/4-in.-thick foam. Then somebody suggested "craft foam," which I had never heard of. Sure enough, it's found in craft stores. I was skeptical but it turns out to be good stuff, and dirt cheap too. It comes in 2mm, 3mm. and 6mm thicknesses.

So, long story short, I got my hands on some 6mm craft foam, traced the hole, rough cut with scissors, and used combination of belt sander and drum sander to finish shaping (something I learned at work - most foams sand fairly well). A couple of pointers here: give up on the idea of a symmetrical plug if you want a tight fit - the hole won't be symmetrical. Also - if you trace the hole you'll probably have to take an extra 1/16th inch off all the way around, due to the chamfered hole edge.

I then coated the plug with contact cement, allowed it to dry, put the plug in the drive hole and carefully pressed the foam fairing on from underneath the boat, to assure alignment.

Here are some pics. It's sits almost perfectly flush over the last 2/3's of the plug's length. It''s ~1/8-inch high at the very front.

Image

Image


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PostPosted: Tue May 11, 2010 4:30 pm 
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Joined: Wed Nov 26, 2008 4:36 am
Posts: 837
Location: Gippsland Lakes Victoria Australia
Nice job - I particularly like the use of the saddle clip, providing a way of securing it when it's removed for pedalling.
I know of one instance where someone had it washed o/board by sea waves due to lack of means to secure it but still have it close at hand.

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Mickey
2016 AI Hibiscus
purchased NEW Nov 2021 - My 5th
Adventure Island Sailing since 2008


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PostPosted: Tue May 11, 2010 6:31 pm 
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Yeah - I invested $25 in what will probably be a lifetime supply of West Sytems Gflex epoxy for that bit. It's made for difficult plastics and metals. Here's a video where they chainsaw a polyethylene kayak in half and edge-glue it back together:

http://westsystem.com/ss/g-flex-torture-demo/

For polyethylene, they say to wipe it down with alcohol and then "flame treat" it - which is to say you wave a propane torch over it for a second (just to "oxidize the surface" - no visible change occurs). The guys at work say that I wasted my money on the Gflex - everything sticks better to poly after you kiss it with a torch. But Gflex is "toughened" (i.e. flexible) where most epoxies are brittle, so it's probably best.


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PostPosted: Tue May 11, 2010 6:50 pm 
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Joined: Wed Nov 26, 2008 4:36 am
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Location: Gippsland Lakes Victoria Australia
pablo wrote:
Yeah - I invested $25 in what will probably be a lifetime supply of West Sytems Gflex epoxy for that bit. It's made for difficult plastics and metals. Here's a video where they chainsaw a polyethylene kayak in half and edge-glue it back together:

http://westsystem.com/ss/g-flex-torture-demo/

For polyethylene, they say to wipe it down with alcohol and then "flame treat" it - which is to say you wave a propane torch over it for a second (just to "oxidize the surface" - no visible change occurs). The guys at work say that I wasted my money on the Gflex - everything sticks better to poly after you kiss it with a torch. But Gflex is "toughened" (i.e. flexible) where most epoxies are brittle, so it's probably best.

Wow - that is one crazy video :shock: However I guess it proves how good the product is.
I hope Stringy sees this - he'll be interested I reckon.
I thought you had just screwed the saddle on with self tappers and used a bit of silicone to finish it off :roll:
Very interesting product - thanks for post :wink:

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2016 AI Hibiscus
purchased NEW Nov 2021 - My 5th
Adventure Island Sailing since 2008


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