Wakeboard tower installed/ gel coat cracking. help

[Rinker97]

I've been doing some research and it seems like there's several different ways to install wakeboard towers. So here's what i did, I drilled the holes in reverse i chamfered the holes installed the rubber the mounts and even applied epoxy to the back up plates. I did all this in a few hours everything came out nice and sturdy thought i did a good job. I went to the lake yesterday between me and a couple friends we wakeboarded about 30 times then i noticed some gel coat cracking in the front two mounts my question is why did this happen? did i have the bolts to tight or is it because the plates are not flat? is there a way to stop this and prevent this from getting worse with out spending tons of money?

 

[brick75]

Re: Wakeboard tower installed/ gel coat cracking. help

That sucks man. I'm about to install one myself, and have had concerns about this. I've done some research on installation techniques, and it sounds like you did most everything right. I don't think overtightening the bolts would lead to that. I've always heard that you want to be sure they are tightened up well.

The only thing I can see that may be leading to the cracking is the use of flat rubber mounting rings on a curved surface. Seems odd that it happened so quickly though. Everything I've seen regarding this indicates that it will happen over time, not right away. Sampson towers will provide mounting hardware that is machined to the curvature of the specific boat it's being installed on. That definately comes at a price premium though.

I'm going to be taking the suggestion of another guy on the forum, and shaping 1/4" hard plastic mounts made at a local plastics store to the curvature of the boat's surface. Hoping that'll do the trick.

Not sure if there is a way to stop the cracking. You might want to post in one of the other forums that are more related to fiberglass repair to see if you can get advice from people that might not be in the wakeboarding forum.

 

[Rinker97]

Re: Wakeboard tower installed/ gel coat cracking. help

Yeah i read that post about the plastic sounds like a good idea, ive never heard of a plastic shop ill have to look into it...


The bolts were a 1/4 inch i drilled the holes a 1/4 inch, I'm wondering if the holes too tight causing it to ream out every time theres pressure or movement on the tower? If i drilled the holes 5/16 would that be better maybe that would put more pressure on the back up plates instead of the fiberglass

 

[craze1cars]

Re: Wakeboard tower installed/ gel coat cracking. help

I know that tower! DIY Wake Pro Swoop! I just installed the exact same one on my boat. Look familiar??
http://forums.iboats.com/attachment.php?attachmentid=52145&d=1273157260

I found those 2 aluminum brackets to be wayyyyy too small to distribute forces on the backside for me to feel good about it. One of the places DIY really cheaped out IMO. So here's a pic of how I inexpensively backed mine up to distribute forces long and high to hopefully prevent this problem:
http://forums.iboats.com/attachment.php?attachmentid=52148&d=1273157330

I need to tell you that weather has not been cooperating, and I have not ridden with this tower yet. So I can't 100% vouch for whether my setup will work or not. Should know more in a few weeks.

I will however agree on the comment about the curved surface that you mounted those rubber pads to. The mounting location is far too curved. I can see air between the rubber and the boat in your photo. And I am quite certain that's contributing to your problem more than anything else. These rubber pads need to be mounted on a very flat surface, or else you need to find some sort of curved replacement for the flat rubber pads. My surface is nearly completely flat, especially compared to yours, so I don't expect this problem. A piece of machine aluminum that follows the contour of your sharp curve at that location could be made, and it could be made oversized to cover your new cracks. I'd expect any machine shop should be able to make feet like this. They'd need your boat to mold the curve. I also like the hard plastic idea...but I too have no idea what the heck a "plastic shop" is or where I'd find one. And I think you'd still want a gasket of some type between the aluminum (or plastic) and the gelcoat, but it wouldn't need to be as thick as the one DIY provided.

Frankly I don't see much other option for you. And I do belive the cracks will continue to spread and get worse if you don't take action before using it again. I think your boat is not really a good candidate for these types of mounting feet, since it appears to have few flat surfaces for you to mount the feet to.

Anothing thing I did was partially counter-sunk the drilled holes on the outside of the gelcoat using a rounded dremel tool grinding stone...sort of like this one:
http://www.dremel.com/en-us/Pop-ups/Pages/ProductImages.aspx?pid=517&tab=1
I recall reading instructions from another tower manufacturer that recommended doing this to help prevent the thru-bolts from contacting the brittle edge of the gelcoat and possibly starting a crack.

BUT...I really really think your #1 problem is the sharp curve where your mounting feet are installed...compounded by the small backing plates.

 

[rabiddawg]

Re: Wakeboard tower installed/ gel coat cracking. help

I just spent about three hours grinding the back side of my mounts so that they fit the curve of my boat. I started with a grinder then finished up with some "file board" sandpaper taped to the boat where it will mount.

 

[splicer]

Re: Wakeboard tower installed/ gel coat cracking. help

I don't have a tower yet, but have been doing a lot of reading on it. You should have reinforced the fiberglass, or added a wood backing plate to distribute the force over a larger area.

What was the thickness of the fiberglass where you drilled the holes?

 

[cpubud]

Re: Wakeboard tower installed/ gel coat cracking. help

those strips are way to small to have any real way to distrube the stress,

 

[Rinker97]

Re: Wakeboard tower installed/ gel coat cracking. help

The fiberglass was probably a 1/4 inch thick. Which is probably my problem seems thin to me.

 

[Hansolo99]

Re: Wakeboard tower installed/ gel coat cracking. help

OK this is what you do. First undue the nuts and take off the brackets on the inside. Then go to the hardware store and get some good wood. You can use 1/4 plywood and some liquid nail. I used a solid peice of would just over 1/4 inch. Then cut 4 (2 for the rear and 2 for the front) peices about 4" X 8" and drill 4 holes to go over the the bolts for the legs (drill these large enough so there it is not a tight fit). Test fit it and after all is fine load up the rear of the wood with liquid nail slide it over the bolts, put the aluminum plates on the back of it then the bolts and crank it down. Do it so the liquid nail squirts out the sides as this will help form to the inside of the hull. the piece of wood will help to spread the stress. Let it sit and dry and the following day tighten it up even more. The plates are too small and the cracks appear to be where the rear braces are. Now some people will say to treat the wood or use fiberglass, but the wood will never see water unless you sink it and if that happens who wants the boat anyways. This works trust me I have done more then one......

 

[Rinker97]

Re: Wakeboard tower installed/ gel coat cracking. help

OK this is what you do. First undue the nuts and take off the brackets on the inside. Then go to the hardware store and get some good wood. You can use 1/4 plywood and some liquid nail. I used a solid peice of would just over 1/4 inch. Then cut 4 (2 for the rear and 2 for the front) peices about 4" X 8" and drill 4 holes to go over the the bolts for the legs (drill these large enough so there it is not a tight fit). Test fit it and after all is fine load up the rear of the wood with liquid nail slide it over the bolts, put the aluminum plates on the back of it then the bolts and crank it down. Do it so the liquid nail squirts out the sides as this will help form to the inside of the hull. the piece of wood will help to spread the stress. Let it sit and dry and the following day tighten it up even more. The plates are too small and the cracks appear to be where the rear braces are. Now some people will say to treat the wood or use fiberglass, but the wood will never see water unless you sink it and if that happens who wants the boat anyways. This works trust me I have done more then one......

That sounds like a good idea but if you click on that pic i posted with the back up plates you'll see its not a flat surface is that wood gonna take shape to the inside of the boat after its tightened? Also what about the mounts will those be ok flat mount on a rounded surface?


Any ideas on how to get those plates off that are epoxyed on there?

 

[superpop]

Re: Wakeboard tower installed/ gel coat cracking. help

You can throw a whole sheet of plywood behind the mounts, that is not the problem, the problem is you are bolting a flat piece of aluminum to a curved piece of glass. try bolting a curved sheet of glass to a flat piece of metal and see how fast the glass breaks, now take a flat piece of metal and bolt it to a flat piece of glass, it will not break nearly as fast if at all. If it was me I would go get one of those hard white plastic cutting boards and cut out 4 mounting pads to be the same size as the metal mounting pad, then get a belt sander or curved sander and sand the right contour of the curve on the boat to one side of this disc you have made, then mount the tower using these discs. That is the only way you will avoid these cracks. Samson has a video on their website that explains this very clearly. The knuckle heads at these generic tower companies think a fat piece of rubber will compensate for this and it does not, and then you trash your boat and end up with cracks etc. You are putting a ton of pressure and load in a very small area and it needs to be distributed evenly. Bummer about the cracks.

 

[Hansolo99]

Re: Wakeboard tower installed/ gel coat cracking. help

You can throw a whole sheet of plywood behind the mounts, that is not the problem, the problem is you are bolting a flat piece of aluminum to a curved piece of glass. try bolting a curved sheet of glass to a flat piece of metal and see how fast the glass breaks, now take a flat piece of metal and bolt it to a flat piece of glass, it will not break nearly as fast if at all. If it was me I would go get one of those hard white plastic cutting boards and cut out 4 mounting pads to be the same size as the metal mounting pad, then get a belt sander or curved sander and sand the right contour of the curve on the boat to one side of this disc you have made, then mount the tower using these discs. That is the only way you will avoid these cracks. Samson has a video on their website that explains this very clearly. The knuckle heads at these generic tower companies think a fat piece of rubber will compensate for this and it does not, and then you trash your boat and end up with cracks etc. You are putting a ton of pressure and load in a very small area and it needs to be distributed evenly. Bummer about the cracks.

DUMB IDEA!! TRUST ME ON THIS. YOU NEVER want to use a peice of thick HARD plastic the rubber will work fine. Do what I said. The wood will do the trick and it is flexible enough to help distribute the movement. You can use fiberglass, but guess what you will need some wood to thicken up the area. It is the gel coat that is cracking not the fiberglass. The stress is coming from behind the mount not the front. The liquid nails is what will contour to the shape of the inside of the HULL that is why I said to lay it on thick. I will snap pics tomorrow of one that we did 2 weeks ago if you like?? I have installed towers for years and this is the way to do it. Again LIQUID NAILS and a PEICE of wood will work!! And for all these guys saying that a thick peice of rubber on a universal tower will not work it does work it the rear that is making the crack. The strongest part is the curved part in the outside of the boat (like an egg) the problem is the inside curve you are trying to flatten by trying to crank down on the nuts with those small aluminum plates. PM me if you want some pics tomorrow.....Good luck!!

 

[superpop]

Re: Wakeboard tower installed/ gel coat cracking. help

I assumed the OP and anyone else was intelligent enough to deduce that I was talking about creating a hard shim on the outside of the boat, not on the inside. The backing plate would be fine if the outside contours matched, which they do not. All of the force of the torque from the bolts as well as the load from the tower is being placed on the crown of the curve and causing it to crack. If you go to www.samsonsports.com and watch the video on how to install a tower, they do a very good job of explaining why you need a contoured shim on the outside of the boat when bolting a flat mount to a curved surface. The rubber shim on the outside does nothing but cushion the load on the crown of the curve. You need a hard mated surface on the outside or the gel coat will crack, just like it is doing.

 

[craze1cars]

Re: Wakeboard tower installed/ gel coat cracking. help

Honestly I think you are both right, and I think it needs both...and I don't see why the little slap-fest is necessary.

Sampson video is a good one and it shows they utilize both concepts. They make a curved mounting bracket for the surface to match the hull (WITH a piece of soft rubber underneath the curved mounting bracket to allow a bit of cushion. I really like the hard plastic cutting board idea, but I do not think it would be a good idea to just put the hard plastic against the outside of the boat without a cushion or gasket of some type...I think it would be too free to slip and would create extra stresses on the bolts) Note Sampson also provides a much larger backing board on the inside (I think they use thinner bendable aluminum or plastic if I remember so it matches the inner contour of the curve...not wood...it's been a while since I watched the video...but wood should work as well) to help distribute the force among a larger area. They'll also show you the little ball grinder I used to countersink the holes in the gelcoat. Several of their install concepts I felt were EXCELLENT so I copied them the best I could for my install, even though DIY didn't mention any of them, and hopefully I will have good results.

As for getting the metal plates off that you epoxied on the inside. Cured epoxy often softens with heat. Try a heat gun on a low setting (or maybe even a hairdryer on a high heat setting??? But I don't think that a hairdryer will get hot enough. Maybe. Caution on the heat gun. It CAN get hot enough to melt your carpet, etc.) Hopefully with some heat it softens, then maybe you can scrape off with a putty knife. If it doesn't start to soften with some heat from a heat gun, STOP! I'd hate to see you overheat something and cause yet more damage.

I have no idea what kind of epoxy you used. Find the name brand on-line and contact the company to see if they have removal tips.

Alternately I think you could also just leave them there. With a LOT of extra liquid nails/epoxy or whatever, you can just fill the gap around them and put a new backer board right over top of them, then some big wide fender washers before you put the nuts on the bolts. Pretty sure your bolts will be long enough to go through all that. In my pic I linked above I used 3/4" ply, which was far thicker than necessary, and won't bend to your contour. My bolts were barely long enough. But I think if you use 1/4 or 3/8" ply your bolts should be long enough, even if you have to leave the plates buried in the epoxy below the board.

 

[ThreeMileBayWaker]

Re: Wakeboard tower installed/ gel coat cracking. help

Like I said in other posts, you get what you pay for with these universal towers. Those flat mounts that are supplied with the kits are the culprits. Because all the weight it being place on the high point under them, cause the gel coat to crack. Only way to stop that gel coat from cracking is to remove your tower. Sand the gel coat down to fiberglass and build the gel coat back up again or those cracks will only get worse/spread.

I had a speaker fail on my boat and when I popped the speaker out i saw the rear mounting brackets that were factory installed and they are 4"x4" plate, and my outer mount has the curvature of the boat, as Roswell designed this tower exclusively for Glastron as its not even listed on their site.

What my mounting feet look like, notice the bevel..

 

[oldjeep]

Re: Wakeboard tower installed/ gel coat cracking. help

You might not have had a choice on your boat, but as others have said - mounting flat plates to a curved section of the hull is going to cause damage. The load cannot be effectively distributed with part of the bracket being off the boat and the bracket probabally rocks when under load.

 

[Rinker97]

Re: Wakeboard tower installed/ gel coat cracking. help

Thanks for everybody's advice. The back up plate i know will be a easy fix, The mounts are what I'm worried about use a cutting board to make an adapter plate seems like it wouldn't look right. Does anybody else have any other ideas to make something that would work for the mounts before i start cutting up a cutting board? lol

 

[oldjeep]

Re: Wakeboard tower installed/ gel coat cracking. help

I guess what I would do is to get a 1/4" piece of aluminum cut that matches your mounting plates. Then sand the boat profile into one side. Stick that plate between the mount and rubber pad.

Problem that this will cause is that the legs will have to be spread up to 1/4" further on each side.

 

[superpop]

Re: Wakeboard tower installed/ gel coat cracking. help

The hard white cutting board, if cut and sanded into a circle, will simply look like a white shim. You need something pretty hard to spread the load out across the gel coat and glass. I suppose you could use some polished aluminum disks but they are going to be a bear to sand out to match the contour of the curve.

 

[superpop]

Re: Wakeboard tower installed/ gel coat cracking. help

Unless you have a CNC machine lying around. The other thing you could do is call Samson and see if they will sell you the shims for your boat, I doubt it but they might.