On the subject of Gel Coat and go faster coatings
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=13832
Printed Date: 28 Jun 25 at 4:25am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: On the subject of Gel Coat and go faster coatings
Posted By: iGRF
Subject: On the subject of Gel Coat and go faster coatings
Date Posted: 06 Sep 21 at 3:33pm
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Heard of an interesting subtance being use by one of my enthusiastic speed sailing kiter friends. It's a super hard ultra none abrasive epoxy coating developed in the dizzy world of Americas cup boat building, can't exactly remember what it was called, durepox? Something like that. He's built a kite board from it as part of his continued quest to raise the Weymouth Harbour speed record beyond the reach of anyone else. (Usually windsurfers).
But it's one of those substances that allegedly increase the speed of any given hull by 5% due to its slippery nature. One wonders where else it might have already been applied? ;-) 
Either way, if only for it's ultra hard abrasion resistance it's something we should know more about, particularly those of us who live with beach riding.. Anyone know more? ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Replies:
Posted By: davidyacht
Date Posted: 06 Sep 21 at 3:49pm
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Not sure that Durapox is unusually slippery, and if something gave a 5% increase in speed we would all want to have some of it! I think that you will find that Durapox is a two part coating system that is favoured by yards since it is pretty tolerant to different substrates, fast to coat, and is easy to fair before it is fully hard. My personal experience is that it is too easy to cut through it when wet and drying despite applying multiple coatings. It is also not easy to get in small quantities and I think the suppliers will only supply the trade. Personally I will stick to two pack poly for my foils (which is what I used the Durapox for). ------------- Happily living in the past |
Posted By: Oatsandbeans
Date Posted: 06 Sep 21 at 4:39pm
| I doubt if Durapox is any slippery than a 2K PU. What was slippery was Grafspeed around in the early 70s filled with graphite . Just make sure you didn’t rub up against it or you would end up looking like you spent the day down the pit. It probably wasn’t any faster anyway, but who’s to know ? |
Posted By: davidyacht
Date Posted: 06 Sep 21 at 6:35pm
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Who remembers Smoothy? ------------- Happily living in the past |
Posted By: 423zero
Date Posted: 06 Sep 21 at 7:01pm
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Millions of bubbles have been released down Hull in an attempt to reduce drag, don't think it worked. ------------- Robert |
Posted By: sargesail
Date Posted: 06 Sep 21 at 7:37pm
Don’t mention bubbles in dinghy construction when Graf is around….down the rabbit hole we go…. |
Posted By: Oatsandbeans
Date Posted: 06 Sep 21 at 7:52pm
| Yes there was a white soft paint which was called go- fast-smooth made by Helmsman Paints. Easy to get a smooth surface but soft as anything so wouldn’t stay good for long. |
Posted By: 423zero
Date Posted: 06 Sep 21 at 7:57pm
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https://www.sciencedaily.com/releases/2016/09/160902125334.htm
Got to be big bubbles according to this paper, can reduce friction by 20% ------------- Robert |
Posted By: Sam.Spoons
Date Posted: 06 Sep 21 at 11:15pm
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Grafspeed and the Helmsman white stuff worked simply 'cos it was easy to get a very smooth and fair finish with it. I used grey hi-build cellulose primer on my Div 1 boards to achieve exactly the same effect. Not sure it was faster but the grey dappled finish on my Superlight was great for psyching out the opposition . the 'bubbles' thing was possibly a reference to the extruding polymers applied to some boats back in the day before it was banned? ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: Oatsandbeans
Date Posted: 07 Sep 21 at 5:42am
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Yes paints have come a long way from those systems. The epoxy high build surfacers allowed you to get a lot of paint on in one go. Let it dry overnight-flat it back the next morning (really easy as it was still not very cured). It would then cure off over the next days giving a hard fair base for a top coat. It is easy to get a good finish with minimal work involved.
On the “bubbles “ thing sounds like what the Ruskies are doing with their latest hyper speed torpedo-it has a gas generator so it travels in its own bubble ,allowing it to go super fast ( allegedly!) |
Posted By: PeterG
Date Posted: 07 Sep 21 at 9:25am
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I loved the Grafspeed in the bottom of my mirror back in the 60s. As Sam says, the big advantage was that is was easy to sand very smooth - and unbelievably messy to do. But it was also great at absorbing the rays when it was sunny. I made the mistake of leaving it upside down for a week one summer and when I came back it had blistered up all over. ------------- Peter Ex Cont 707 Ex Laser 189635 DY 59 |
Posted By: fab100
Date Posted: 07 Sep 21 at 4:34pm
Me Never found it as easy to sand flat as they claimed and found it cracked on my Mirror until the bottom looked like crazy paving. Cute Mr Sheen story ------------- http://clubsailor.co.uk/wp/club-sailor-from-back-to-front/" rel="nofollow - Great book for Club Sailors here |
Posted By: aardvark_issues
Date Posted: 10 Sep 21 at 4:04pm
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There's Durepox and there's Durepox. The Moths have been using Durepox primer for foil finishing since forever - you've got a nice few days window from spraying to flatten back to a smooth finish before it goes really hard. The Durepox topcoat I think has PTFE in it if I remember rightly. Also goes pretty hard and I'd probably use it over a 2 pack polyurethane or 2k car paint. Done a couple of boats with it and it's nice enough. ------------- http://www.aardvarkracing.co.uk" rel="nofollow - Home of Rocket Racing |
Posted By: iGRF
Date Posted: 10 Sep 21 at 6:25pm
This stuff is pretty new, so I've probably got the name wrong, whatever it is they are interested enough to ask for stickers for the speed record attempt, I'll try and find out more, might see him at an event tomorrow. ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Posted By: iGRF
Date Posted: 14 Sep 21 at 1:56pm
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OK, so I have an update, this is a new Durepox Extreme version even tougher and slippyer, will report more news when I have it, have also come across an incredible new foam that withstands amazing loads yet is almost as light as EPS it's being used by a new Surfboard manufacturer called Appletree who's boards we now rep over here. Interesting the march of development still continues. Lots of exciting development coming out of Portugal of all places thanks to massive EU investment. ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Posted By: fab100
Date Posted: 22 Sep 21 at 2:47pm
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It appears GRF's go-fast bubbles finally may be a go-er: “Carpets of bubbles” will soon save shipping giant MSC £220m in fuel costs after it signed up to put a British company’s revolutionary technology on a fleet of new cargo ships. MSC will install https://www.silverstream-tech.com/" rel="nofollow - Silverstream Technologies’ “air lubrication” design on 30 container ships it has ordered from southeast Asian shipyards." https://www.telegraph.co.uk/business/2021/09/22/carpets-bubbles-slash-fuel-costs-container-ships/ ------------- http://clubsailor.co.uk/wp/club-sailor-from-back-to-front/" rel="nofollow - Great book for Club Sailors here |
Posted By: Paramedic
Date Posted: 23 Sep 21 at 7:37am
Coming soon to a wayfarer near you
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