Repairing small drill holes in hull

As mentioned when I started this thread I considered using G/flex. I have since went ahead and tried it on a couple of applications, one filling holes left from a removed transducer, and the other filling and repairing a horizontal canvas snap that had worked itself lose.
In both instanced the product seemed to work well and the syringe applicators that come with the produce worked great for back filling the transducer holes; had to tape over the transducer holes to keep the epoxy from running out. I also over drilled the holes some to clean them out.
When I eventually upgrade my sonar it will be with an in-hull transducer, no more holes drilling in the transom; unless I opt for trim tabs.
 
Jay,
Where are you going to put the "in hull" transducer? To my knowlege the entire bottom hull of the C Dory 22 is cored (the only exception may be the small area just in front of the drain plug, where the bilge pump is located--and this may be solid???.

A depth finder (ultrasonic) transducer will not shoot thru a cored hull. The balsa core interface will stop the beam. If you want to shoot thru a cored hull, you have to remove the core. Then under cut the edges of the balsa core, finally glass over the bottom (since is is no longer as thick or strong)--and then install the transducer in this area with no core--using either mineral oil, epoxy or silicone sealant.

The other option is to cut a hole in the hull with a hole saw. In that case it is essential to undercut the core, and fill it for at least half an inch (to avoid crushing the core as you tighten the nut on the thru hull transducer. (This is a thru hull installation). Both of these are far greater challanges than the filling of transom holes and using a poly block.
 
thataway":oiqryqvo said:
Jay,
Where are you going to put the "in hull" transducer? To my knowlege the entire bottom hull of the C Dory 22 is cored (the only exception may be the small area just in front of the drain plug, where the bilge pump is located--and this may be solid???.
Click to expand...

Bob
From what I understand this area is solid, and there’s plenty of room for an in-hull transducer; could be wrong but that’s the plan.

Now this isn’t going to happen anytime soon, but if I can get a good deal on a 1KW RMS sonar off e-Bay it may happen sooner. Not that I’m totally dissatisfied with my current Garmin 250C with its 400 watts RMS, but it just don’t cut the mustard in deep water.

So your probable wondering why in the world do I need accurate returns from that far down? Well, the shrimp we go after up here hang out from 400 to 800 feet, and I’ve had fantastic luck in 600 to 700 feet. Now most the time I can get an accurate return from 650 to about 700 feet, on a good day. When you set on the shrimp its usually desirable to drop your pots up hill on a steep slope, if you miss the mark by as little as 100 feet you could be dropping your first pot into to abyss-no kidding. When you see pot buoys floating by in 1300 to 1500 feet you know someone missed the mark.
 
In rummaging thru my garage, I found a bunch of System 3 epoxy and hardener that came with a kayak kit. Any reason I can't use this stuff instead of the West system epoxy that everyone is recommending here?

I'd be using it to fill the holes below waterline that were drilled by the previous owners for a couple of transducers and trim tabs. Also for whatever new holes I drill to place Starboard (HDPE) onto the spot for teh new transducer and other such toys.

So back to the question: Is System 3 an acceptable alternative to West for epoxy use below waterline?
 
System three is an excellent epoxy. (Actually few of the retailers actually formulate the epoxy--they buy it from large chemical companies--when we were building boats we got epoxy in large containers which had "Shell Chemical" on the outside.)

For some reason System Three seems to have caught on more with the kayak builders. As long as the proper ratios are used, it will work fine.
 
Thataway, thanks for the reply here, and on my heater question today over in the other thread. I'm looking forward to getting these holes filled.
 
Dr. Bob et al,

So I'm getting ready to install a new transducer. I purchased a transom mounting board and want to be sure I'm understanding the above conversation.

It IS ok to use MarineTex to fill in the existing holes and the oversize holes for the mounting board screws? These filled holes would be below the waterline. I haven't mixed epoxy and am comfortable using MarineTex.

You crosscut the back of the board with a dremel tool and slather 5200 on the board to adhere to the transom gelcoat?

How many screws do you use to adhere the mounting board to the transom? 1, 2?

You dip the transucer mounting screws in 5200 before attaching to the transom board?

Is that it? Anything else to add?
 
Mix the MarineTex according to instructions--There is a moderate tolerance of the ratio of hardner to epoxy. The MarineTex needs to be worked into the holes in the transom with a tooth pick or other thin piece of wood. We bought a box of 1000 popsicle sticks at the hobby shop a few years ago, and use these for mixing epoxy and small amounts of polyester resin. We cut these to the width we need for each project.

I put the 5200 on the back of the Starboard or other high density polyethylene board. I usually use two screws into the hull--with holes drilled out and epoxy filled. No sealant between the 5200 and the block of Starboard.
 
Jazzmanic":wjx82o52 said:
Dr. Bob et al,

It IS ok to use MarineTex to fill in the existing holes and the oversize holes for the mounting board screws? These filled holes would be below the waterline. I haven't mixed epoxy and am comfortable using MarineTex.
Click to expand...

Used the G/flex on the transom to fill holes from old transducer, worked great as far as I can tell.
Over drilled the holes a little and wallard them out some, back-filled the hole by injection, than slapped some tape on to hold it in; cures relatively slow.

Dang, just notice I started this thread.
 
breausaw":23hn45nn said:
thataway":23hn45nn said:
Jay,
Where are you going to put the "in hull" transducer? To my knowlege the entire bottom hull of the C Dory 22 is cored (the only exception may be the small area just in front of the drain plug, where the bilge pump is located--and this may be solid???.
Click to expand...

Bob
From what I understand this area is solid, and there’s plenty of room for an in-hull transducer; could be wrong but that’s the plan. .
Click to expand...

C-Dory factory told me that the recessed area around the bilge pump/drain plug also has balsa core although it is thinner than the rest of the bottom.
 
This is pretty crazy, but a year ago when I put on my transducer on a white piece of Starboard, (as suggested on this site) I found a spray paint at Wal-Mart, royal blue I think for plastic, that was pretty close to the gel coat color on the boat bottom (couple bucks). After installing the Starboard I masked it off, wiped it with acetone and spray painted it blue prior to the ad on.

Since I didn't sand it or anything, I assumed the paint would likely scratch and flake off pretty quickly. Well, it's been about a year and it's still pretty hard to see the starboard from any distance and the dang stuff's still adhering like it was made for starboard.

Your results may vary.

Jay, in that little area make sure your puck is as far from the keel as possible and let us know how that works out please.

Chris
 
Thanks guys. One last question. Do I need to wait until the weather gets a little warmer to do the project? I really want to get it done by mid-March and the temps will still be in the 40's-50's.
 
Amines (the constituents which provide the reactions in vinyl and polyester Rxns) are highly dependent on temperature. There should be statements on the containers indicating the optimal range of temperature conditions which result in best working conditions. I am not certain of every product's temperature conditions, but I strongly suggest remaining within those guidelines.

I suggest the air temperature (if at all possible), the hull, gel coat, etc, and the poly- or vinyl- ester materials you are working with are all at the same temperature if possible. Generally, this is 25C at MSL.

m2cw
 
OK, I just got around to doing this. Backed out 14 screws from transom, including the ones that had held on the dastardly "Smart Tabs" that made the boat run like a Weeble-Wobble.

Screw holes in the transom above waterline (4 of them) were dry. Screw holes in transom below waterline, not so nice. I filled 'em all with Marine Tex.


A couple of comments:

1) It's damn hard to use an Allen wrench to undercut a small screw hole. My screws were all #12 or #10, and no Allen wrench of decent thickness would fit into teh hole cockeyed and then be rotated straight to be turned by a drill chuck. Did I miss something? I ended up cutting the short end of the wrench even shorter, but even that was tough.

2) Is there any kind of important difference between Marine Tex and JB Weld? Other than the 300% price difference? It looked like JB Weld...smelled like JB Weld....set up like JB Weld.....

Next up are the 25 roof holes. It's a non-core roof. Any reason I can't just use 5200 up there instead of the insanely difficult (and expensive) Marine Tex?

(If you can't tell by now, I'm not a huge fan of Marine Tex).
 
Don't let Bob know, but I fill all boat holes with 5200. That stuff is so hard to use it's got to keep the water out. And since it's a putty/paste, it fills all the cracks and holes. Above and BELOW the waterline. There, Bob, I've now said it.

As to JBWeld, it's just a strong epoxy with aluminum filler. I saw it used to fix the head of a diesel in the South Pacific. The engines ran afterwards, just don't know if they made New Zealand. Great stuff, saved my aft section many times. Never used Marine Tex, but if it's just a filled epoxy, I'd prefer JB Weld. I know that stuff works in water, oil, etc. on fiberglas, magnesium, steel and wood. Now that you mention it, I used JB weld to plug a hole in Journey Ons cabin top. It's that little grey hole above the head, where that cabin top is only 1/2" thick, and I don't mean 9/16".

Unless you're trying to tell me that Marine Tex is cheaper than JB Weld. If so, disregard the above.

Boris
 
OK, I just got around to doing this. Backed out 14 screws from transom, including the ones that had held on the dastardly "Smart Tabs" that made the boat run like a Weeble-Wobble.

Screw holes in the transom above waterline (4 of them) were dry. Screw holes in transom below waterline, not so nice. I filled 'em all with Marine Tex.


A couple of comments:

1) It's damn hard to use an Allen wrench to undercut a small screw hole. My screws were all #12 or #10, and no Allen wrench of decent thickness would fit into teh hole cockeyed and then be rotated straight to be turned by a drill chuck. Did I miss something? I ended up cutting the short end of the wrench even shorter, but even that was tough.

2) Is there any kind of important difference between Marine Tex and JB Weld? Other than the 300% price difference? It looked like JB Weld...smelled like JB Weld....set up like JB Weld.....

Next up are the 25 roof holes. It's a non-core roof. Any reason I can't just use 5200 up there instead of the insanely difficult (and expensive) Marine Tex?

(If you can't tell by now, I'm not a huge fan of Marine Tex).
 
After I purchased my boat I removed all the hardware to drill out the coring and then epoxied. I used small thin finishing nails that I bent at 90 degrees to drill out the coring. The sharp point at the end of the nail does a nice job of removing the coring.
 
Off topic,
Mcdory,
There might be more appropriate forums to express your political leanings.
This is a boating forum??

Respectfully,
JT :thdown
 
Siddfynch
I don't mean to hijack this topic but I just had a look at your photos and it looks like you are missing about 6" of rubrail rubber on the starboard side at the bow.
Is that the case?
If so, I have a 1981 classic and am missing that exact same amount in the same place.
Any idea where to get some more?
Tnx, Jimbo
 
Jimbo":py6wudet said:
Siddfynch
I don't mean to hijack this topic but I just had a look at your photos and it looks like you are missing about 6" of rubrail rubber on the starboard side at the bow.
Is that the case?
If so, I have a 1981 classic and am missing that exact same amount in the same place.
Any idea where to get some more?
Tnx, Jimbo
Click to expand...

Jimbo, good eye. I haven't shopped around for any. I'll send you and PM when and if I do. It's about #25 on my list of things to tackle.
 
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