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Hull fairing around saildrive

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 23 September 2016 at 11:41pm
Follow up: Tried using 4200 to patch down the loose part and see if it would last the season and it did not.  Peeling off again.
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote frfletch Quote  Post ReplyReply Direct Link To This Post Posted: 24 September 2016 at 12:06am
Chris,

They use a special silicon adhesive for that. I don't have a rubber seal on the bottom so I can't help you unless you want to change to my method of dealing with it. I never liked that rubber thing down there.

Frank
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 24 September 2016 at 3:07pm
The original seal is glued on by a Bostik product that is no longer available here in north america  (A3) - European boats can still get it but it is not safe to air ship so we can't . Crinmar used to supply it with a new seal . Bostik themselves recommended a replacement product called 1685MC which I used this year . It is an industrial contact cement product used to glue on mop heads - very waterproof .  I will let you know how it held up when I pull the boat on Monday but it was still on solid when I dove on the boat at Can Am .  Still have some left if you are anywhere near Niagara Falls . 

Edited by John Mills - 24 September 2016 at 3:08pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 12:18pm
Update , the  Bostik 1685MC held great , on just as solid as when it went in . 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 1:42pm
I installed a new saildrive membrane before launch in 2014, using the guidelines posted here and I thought I did a very good and thorough job.  Nonetheless, mine is peeling off again after only three seasons, implying I did it wrong although I find that hard to believe.  I was very particular.

I also contacted Krayden and they have the glue (1 litre) at $34.50 but only seem to want to sell it to me in a case of 12!

Since I race PHRF, I think I'll explore Frank's method of a more permanent solution to this so I never need to worry about this rubber again...
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 6:33pm
They shipped me a single can right to my door - I will see if I still have the contact name I used  for you if you are interested .  Seems to hold really well .  Not cheap as they send you a quart where you need about an ounce . 

As to modifying the skin fitting , not sure that is legal under PHRF I would check first  . I would think you become a non-standard boat having modified the hull fittings  and open to a protest , or you will take a hit for it up front  . Same as if you modified a shaft strut ,  keel or rudder attachment  reducing drag.  Not to mention the motor and drive moves around . Bukh did not put a flexible fitting   there for no reason . 

 
Back to the installation. I sanded the area down to gel coat  , inter-protected the entire well , the sail drive and the area the glue would attach to, then followed the glue instructions that came with the can.  Bonded instantly. One season so far and it seems as good as when I put it on, but time will tell. 

Good luck and good sailing whatever you decide to do . 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bal149 Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 8:57pm
Chris, I guess you did not read my previous post..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 9:14pm
Originally posted by bal149 bal149 wrote:

Chris, I guess you did not read my previous post..

Nope I'd read it, but we noticed the small area of the rubber peeling off at the last day prior to launch and 4200 was all I had available.  I figured it might hold for a year especially since it was just a small area.  Clearly not the case...
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2016 at 9:21pm
Frank when you modified Voila did you suffer a PHRF rating hit?
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 29 September 2016 at 8:21pm
Run it past  a PHRF measurer at your club  .  Only way to be sure . 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 30 September 2016 at 12:51pm
Here's our rating chairperson's answer.  Note that different clubs may take a different position.

"I don't think a 1/8 inch reduction of frontal surface will affect form drag significantly enough to warrant a penalty. From pics online of the Bukh shaft seal it is tapered to maintain laminar water flow over the surface. Removing that and going flush with the hull will slightly improve flow but it is around a vertical shaft that generates the majority of the form drag. The seal is negligible in the overall drag of the saildrive lower unit. No penalty."
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 30 September 2016 at 9:11pm
Excellent news .  did you get it in writing ?  I agree that it will make little to no difference to speed and is why I would never take a hit for it . Technically it does not meet the definition of a "standard boat" that being ""Standard Equipment" shall be what the manufacturer supplied. " according to PHRFlo sec 4.3. 

 PHRF is traditionally pretty picky what you do below the water line , nice to see they officially waved this .  PHRF is not a club thing after all , your certificate covers the area you sail in , across all clubs .  

Now to be clear this is something that if you do you are supposed to report it , the rule being " Changes that alter either the weight of the boat *or the flow of water over wetted surfaces such as size, shape, contour, length, materials*, weight, location, center of gravity, etc."   "Materials"  is what it says  and flow over whetted surfaces  .

Don't get me wrong , I don't think it makes any more difference to speed than carrying beer and ice , just don't want to run afoul of the rules.  


Maybe now the class can approve it ? 


Edited by John Mills - 30 September 2016 at 9:33pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 5:04pm
After consideration, I'm going to try re-gluing the original rubber membrane.  After haul out the membrane was still attached but I was able to peel it off easily by hand.

In another post someone mentioned gluing it on and then using some small screws to provide further adhesion.  Seems reasonable to me...

Bostik 1685MC works well according to John but is hard to get.  Only place in Canada that sells it is Tec-N-Tec in Montreal but they charge a ridiculous amount for both the product and shipping.  Krayden in the USA will sell a quart for $34.50 USD so it looks like that is the best option..... unless anyone has found any other high quality waterproof contact cement that works?  I've read that Dap Weldwood contact cement works good for general use.  How about LePage contact cement available at any Home Depot?  It's listed as "water resistant" which is not encouraging but LePage is a good company.  They make Loctite after all...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mad Max Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 5:40pm
Chris

I've been using 3M Super Weatherstrip adhesive with no problems.  Get is at any Auto Supply store.  I know of other people are using it on their sail drive units.  When was the last time you ripped off your weather stripping opening  frozen car door in the middle of winter.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill Layton Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 7:24pm
The original glue used from BUHK is some form of waterproof contact cement. I've installed dozens of these rubbers and they glue so well they are virtually impossible to remove without tearing the rubber apart into pieces. However when I install a rubber, I sand the rubber surface and hull surface well and coat both sides with glue and let it dry tack free before I push the rubber into place. Then I use a roller to roll out the rubber as hard as I can push on it. This is the typical method used when using contact cement. I see many owners suffering the same problem as you folks but it's clear your missing one of these steps. I've never ever been able to remove a rubber I installed without the help of a heat gun (which one must be very careful using) When I hear stories of how the corner didn't stay glued etc I'm certain the standard protocol for using contact cement hasn't been followed. Most rubbers installed at the factory lasted 15 years or more and they only got replace because the rubber cracked around the leg... it did not become unglued. 

Edited by Bill Layton - 18 October 2016 at 7:26pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winner Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 9:06pm
My method for the installation is described on page one of this thread.  In reviewing this, I see a couple of things I may have done wrong:

1) I did not sand the rubber membrane prior to applying the glue (I did sand the hull but perhaps should have even used something a bit grittier at the end)

2) It was a cool day (don't remember exactly).  A warmer day in the mid teens or above seems to be preferred for this type of glue

3) When applying, I did not wait for the glue to dry before pressing the pieces together.  I think I waited until they are a bit tacky and that was it.  But Bill mentions above (and I've seen this elsewhere) to wait until the glue is all but dry before pressing the pieces together.  Counterintuitive, but I guess that's that.

It's too cold here now to apply this stuff so it looks like I need to wait until spring.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill Layton Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 9:43pm
Actually it's not too cold to apply this. I've done it at Zero Celsius a few times without problems. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Mills Quote  Post ReplyReply Direct Link To This Post Posted: 19 October 2016 at 11:21am
This glue is the same kind one would use to glue a linoleum counter top on but more waterproof  . A contact cement . It should be dry when you stick the two together . For the hull you want to be gluing to the gel coat or epoxy paint  , not a bottom paint or old glue scuffed up . 

Not sure about the temp, but it will tell you on the can . 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WarBird Quote  Post ReplyReply Direct Link To This Post Posted: 28 December 2016 at 9:30am

when I did WarBird #169 back in 02 or 03 it was part of a complete bottom job. VC Tar off, Interprotect 2000 on. Boat prep is part psychology. The other guy gets worried when he see all the time and effort YOU put into your boat. Fairing and filling and longboarding as the competitors walk by in the yard get them wondering. My saildrive gasket was sh*t but the previous owner had a new one and the bukh glue in the parts kit. I put a 45 degree bevel around the perimeter of the gasket perhaps more for the "wow" factor than actual flow in that area of the hull. I think I did that carefully on a belt sander feeding it carefullly by hand. When we had 5 L28s racing, WarBird was always at or near the front.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bal149 Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2017 at 4:18pm
So I went off to TecNTec to purchase a litre of glue. Bostik 1685. Pricey at 93.00$ But WAIT! Bostik increased the price as of May first- 225.00 plus tax!!!! WHOA. If the 3m Weatherstrip has held up on those using it I will try this . Can I use it on a previously glued membrane?

Edited by bal149 - 15 May 2017 at 4:19pm
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