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PostPosted: Sun Sep 29, 2013 7:54 am 
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Hello all. I am hoping I can get some repair advice from others that have had this problem. My current situation is that I have two ss gudgeon screws that were broken off inside the transom on my starboard hull during a race in Myrtle Beach (a couple of years ago I am ashamed to say). I don’t think I ever hit anything, must have just been some sort of weird stress on the rudders. I also have to ss gudgeon screws with broken heads on my port side rudder. They are all the upper part of the gudgeon. I have gone through numerous drill bits and hours working to get these ss screws out with little success. I’ve learned to take my time and drill slow, but we are talking hours on one screw here. I have also messed up and gone through the aluminum backing plate in some of the hole locations accidentally. I’ve made some progress, but I need to start thinking about how I am going to make this a lasting repair so I can get back on the water. My boat is pieced together with 86 hulls. She was pretty fast and light last I remember. At this point I’m not really looking to get back into racing just yet, I just want to be able to have some fun with her and the wife on the water. I have the one piece gudgeons and plan on using them.
So, my questions are:
1. Do I just continue to try and drill out the ss screws (I’ve been using cobalt bits), fill with resin and filler (btw I have no fiberglass experience), and then re-tap with a larger size screw?
I really worry about doing this correctly. I think it would be hard to get them all back into the aluminum. Drilling these screws out has not gone well. I’ll get into the screw, but it isn’t perfectly center and the screw eventually sheers off making it even harder to drill out.
2. Do I do the above step and try to glass in helicoils? (seems expensive, compared to other options)

3. Do I cut inspection ports into the stern of each hull to thru-bolt the new gudgeons?

While more drastic, this seems like an ultimately easier and more sure-thing repair. It would also allow me to make sure the transom is sealed.

4. Some option that I do not know about????
I’m open to anything at this point. What would be the fastest, cheapest, and most effective way to do this repair? I’ve got to get back sailing.
I will try and post pics of the transoms in a few. Thanks in advance.

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James
86' Redline Hobie 16
Sail # 76909


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PostPosted: Sun Sep 29, 2013 8:20 am 
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Location: Virginia Beach VA
Quick and dirty as you requested is to go up a size, drill and tap. The original screws are #12-28 I think. You'd need to go to 1/4". 1/4-20 SS are common and easy to find at your local hardware store. You might want to look for a finer thread though as the aluminum backing plate is not very thick.

I've known guys who install inspection ports and nut and bolt them. They had a devil of a time keeping them all water tight though. If your backing plate separates from the inside of the transom you'll have even more problems. I think the backing plate is epoxied in but I'd keep at least two screws in at all times to keep it aligned just in case.


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PostPosted: Mon Sep 30, 2013 11:21 am 
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You don't have to go all the way up to 1/4-20. M6 works nicely. Also, aren't the holes for the cast grugeon in a different place than the stamped ones?


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PostPosted: Mon Sep 30, 2013 1:59 pm 
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Location: St. Louis, MO
I would not thread the new screws in. I would drill out the holes and use a nut and washer on the inside. If you sail in salt water at all and water gets near there you will have corrosion issues again since SS and aluminum do not get along in salt water. Also, with the thinner backing plate you do not have to worry about the threads stripping if you bolt them in place. If you are worried about keeping the holes water tight, here is a simple and effective solution:

http://www.pbase.com/mainecruising/rebedding_hardware

I learned alot about this stuff when I owned my keel boat. Since the Hobies are not left in the water, you are fine to use the butyl tape below the water line. Do not use silicone. It will only work for a short time.

I had great luck with this solution through torrential downpours and tons of green water coming on board. My cabin stayed nice and dry.

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Nick

Current Boat
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Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO


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PostPosted: Tue Oct 01, 2013 6:58 am 
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Location: Wrightsville Beach
Do not cut ports in your hulls, you are just going to create more problems. Its really not that hard to cut out the aluminum plate and glass in a new one. You might also be able to get away with just cutting out the top part of your transom and reglassing solid then drilling and installing new machine screws. I have some pics of this and we had a whole thread on this I will look for it later. Post some pics if you can if not get in touch and I can help you.


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PostPosted: Tue Oct 01, 2013 9:35 am 
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Thanks Genmar, good to hear from you. I miss sailing with you guys. I saw your repair and it looked great. But, you have to keep in mind that I don't have the fiberglass experience that you have. I also probably don't have a lot of the tools that you have. I'd love to get this thing taken care of so I can do some sailing. I think the port hole idea is something I feel comfortable enough with (skill wise) to do. I'd have to have some help if I was doing major glass work. I'd love to get on the water at least once before it gets too cold. If you have a free weekend here soon and want to help me out that would be great. I'd love to learn how to lay fiberglass properly. I'm just afraid I wouldn't do it correctly if I had to do it by myself. Let me know though, I was planning on ordering the ports today. I've waited too long to fix my boat and get to sailing.

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James
86' Redline Hobie 16
Sail # 76909


Last edited by abbman on Tue Oct 01, 2013 4:07 pm, edited 1 time in total.

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PostPosted: Tue Oct 01, 2013 12:36 pm 
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Location: Jersey Shore
I really don't see how cutting in ports is going to create more problems. Lots of boats have deck ports which, if installed properly, actually help eliminate problems. Just be sure to seal the core when installing the plate and the screws (i.e., use silicone caulk). Increased hull ventilation is a major benefit of having deck ports - they allow for greatly increased airflow when when not sailing, so your hulls stay dry.

It is very likely that you can get back out on the water without having to do any glass work. As I mentioned previously, if you cut ports in the hull, it may be possible to pull the broken screws out from inside the hull using a pair of vice grips. Then just install new screws or thru-bolt if the threaded plate gets messed up. Either way, having a port will allow you access to both sides of the transom for whatever repair you need to do - this is a good thing. I would go with the biggest port you can reasonably fit at the transom, probably a 5" port, but may only be able to fit a 4". Lay it out before you purchase and see what will fit. You probably also want to get the ports for curved decks.

sm


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PostPosted: Tue Oct 01, 2013 12:55 pm 
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Location: St. Louis, MO
I installed the ports in the rear with no issues to fix this exact problem. I think they were the 4". There are ports in the catalog for just this purpose and made to fit the deck curvature. Yes, my hulls were much drier. One other benefit is if you forget to put your drain plugs in you can use a manual bilge pump to quickly remove most of the water. A properly installed port behind the rear pylon will not leak.

I would caution you to not use silicone. Once you put it on a surface it is nearly impossible to remove and nothing will really stick to a surface that has been treated with silicon... even more silicone will still fail. The only thing silicone is good for on boats is lubrication. I have already made this mistake and do not plan to repeat it.

To seal the core just remove some of the foam and fill with thickened epoxy. You may want to remove enough foam to account for the mounting holes. Then, look at my previous post for for a link on how to make the screw holes water tight. Look around on that website and you will find information on doing this as well. Granted it is for balsa core boats, but the idea is the same.

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO


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PostPosted: Wed Oct 02, 2013 6:13 am 
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Location: Virginia Beach VA
This discussion seems to have devolved into one about inspection ports. Just to clarify, my comment about leaks were with respect to the nut and bolting of the gudgeon screws and not the inspection ports. When you drill and tap you need only seal the threads. In order to bolt through you need to drill a hole larger than the bolt where you are left trying to fill a gap. These hull penetrations are mostly below the water line when the boat is underway. A good seal around the gudgeon screws is critical.


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PostPosted: Wed Oct 02, 2013 12:53 pm 
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Thanks again everyone. Your advise has been very helpful. I think my best option is to install ports if I am to do the repair myself. Like I said, I know for a fact that some of the screw holes I have either drilled through in the aluminum plate or were stripped through when the gudgeons failed. I am going to have to seal all of that up somehow anyway and the best way to ensure that is done is to cut a hole in the boat. I really liked the article on using butyle tape and I believe I will try that method as well. I also may try to drill and tap the bolts into place as well to try and keep everything sealed up tight.

The screws don't go through the aluminum plate in the original design do they? I was under the impression that the original screws went into, but not through the plate. I guess knowing more about the anatomy of that section of the boat would be helpful. If I'd of thought of it at the time I would have taken a look at some old 83 hulls I finally cut up and sent to the dump.

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James
86' Redline Hobie 16
Sail # 76909


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PostPosted: Thu Oct 03, 2013 6:36 am 
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The original screws are only 1 inch long. They probably thread all the way through the plate with few, if any, threads protruding.


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PostPosted: Fri Oct 04, 2013 6:33 am 
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One final thought....a four inch hole is not much to work with. They call them "inspection" ports for a reason. Your hand will easily cramp trying to get inside and back to the transom to do anything at all. If you are determined to put an inspection port in make it larger if you can.


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PostPosted: Fri Oct 04, 2013 1:33 pm 
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The holes in the aluminum go all the way through. Not sure how deep the screws penetrate the holes, but I suspect if varies quite a bit from boat to boat. There is about 1/8"-1/4" of glass then 1/2" or 5/8" (not sure what is stock, I used 5/8) plywood, and then the al plate(1/4"? maybe a little thinner), probably with some laminating resin in between. Plus the flanges on the hardware. In my case water had been coming in the screw holes so long that the plywood had rotted and I had to pull the whole thing apart, but it was not really that bad of a job. I did not know about the butyl tape, so I tried to seal up the screw holes with silicon, which I suspect did not totally work as I still get a little water in that hull.


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PostPosted: Fri Oct 04, 2013 2:59 pm 
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With regards to the access ports, I would recommend staying with the 4" port since the 5" port's hole thru the top of the hull will put you too close to the ~3/4" diameter bead of hard dried resin (that oozed out between the sides and top of the hull when it was manufactured). This bead will also get in the way of putting all the bolts thru for the 5" access hatch.

I have big hands, so I decided to cut the holes for the 4" ports, do all my work on thru bolting the gudgeons before I installed the 4" plastic ports. The hole that you will cut thru the top of the hull will be ~ 4½" in diameter vs ~ 3½" for the inside opening of the 4" port.

Bill Mattson wrote a good article in On The Wire entitled: Do-It-Yourself: Installing Deck Ports

http://www.thebeachcats.com/news/29/installing-deck-ports/

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Tim
82' H16
Sail # 88863
Panama City Beach, FL
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