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Mojo's Fiberglass V hull Project
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Rat
Well-known member
Wow, are they on the bottom of the hull? It looks like they are. Probably have some oil canning going on, the bottom is flexing while running over chop. That's what usually causes those star shaped cracks. It could have been caused by overpowering the hull, by having too much weight forward of the spray line or just a weak bottom.
It looks like Biax cloth on the bottom, which is good if it is. I would add a lamination of 12 oz Biax cloth to the bottom all they way up to the spray rails to help stop this. Are these forward on the hull or aft? I would also add another strake along the center strake you already have; take it pretty far forward, at least to the bow curve on the bottom. This will help you in corners and will help stiffen the hull without needing to add stringers inside the hull.
Laying the Biax is pretty straight forward. Cut the cloth to cover the intended area, then roll a light coat of epoxy, let it get just tacky feeling, then lay the cloth over and wet it out with epoxy.
The strakes can be made of many woods but good ol' Southern Yellow Pine does a fine job, a 2x2 or 1.5x2 would be all you need. Glue the strakes to the hull using epoxy glue and then cover them with two layers of 12 oz biax tape 6 inches wide, again working wet on wet. The fairing you will need to do will be the lamination edges of the strakes biax cloth, the hull sides by the spray rail and to fill the weave of the cloth.
Biax cloth is sold by the linear yard and is 60 inches wide, two gallons of epoxy will leave you enough to do some other touch ups you may need inside the hull and 1 pound of woodflour will be all you need for making the glue and maybe a pound of silica for fairing compound.
This is a pretty major task so do your research. When you are done the bottom of that hull will be bulletproof!
I can direct you to another forum where they know their epoxy inside and out, much more than I do, and they can give you a bill of materials and also pointers on the best way to proceed and the best materials. They also have the best prices on the net for epoxy, cloth, woodflour and all the other stuff needed for lamination work.
I can PM you the site if you want, or, if it's okay, I can post it here.
It looks like Biax cloth on the bottom, which is good if it is. I would add a lamination of 12 oz Biax cloth to the bottom all they way up to the spray rails to help stop this. Are these forward on the hull or aft? I would also add another strake along the center strake you already have; take it pretty far forward, at least to the bow curve on the bottom. This will help you in corners and will help stiffen the hull without needing to add stringers inside the hull.
Laying the Biax is pretty straight forward. Cut the cloth to cover the intended area, then roll a light coat of epoxy, let it get just tacky feeling, then lay the cloth over and wet it out with epoxy.
The strakes can be made of many woods but good ol' Southern Yellow Pine does a fine job, a 2x2 or 1.5x2 would be all you need. Glue the strakes to the hull using epoxy glue and then cover them with two layers of 12 oz biax tape 6 inches wide, again working wet on wet. The fairing you will need to do will be the lamination edges of the strakes biax cloth, the hull sides by the spray rail and to fill the weave of the cloth.
Biax cloth is sold by the linear yard and is 60 inches wide, two gallons of epoxy will leave you enough to do some other touch ups you may need inside the hull and 1 pound of woodflour will be all you need for making the glue and maybe a pound of silica for fairing compound.
This is a pretty major task so do your research. When you are done the bottom of that hull will be bulletproof!
I can direct you to another forum where they know their epoxy inside and out, much more than I do, and they can give you a bill of materials and also pointers on the best way to proceed and the best materials. They also have the best prices on the net for epoxy, cloth, woodflour and all the other stuff needed for lamination work.
I can PM you the site if you want, or, if it's okay, I can post it here.
Mojo
Well-known member
Rat,
Thanks for the reply. OK.. First.. Those cracks are all over the bottom of the hull. They aren't localized to forward or aft.. but there are more in the rear and middle areas.
You lost me at Strake... yea... not that technically hip on the small boat lingo. There are no stringers on the interior of the boat. It's just a solid fiberglass mold as far as i can tell.
"The fairing you will need to do will be the lamination edges of the strakes biax cloth, the hull sides by the spray rail and to fill the weave of the cloth." I didn't understand what you were talking about here at all. I need some edumication on it please!
Thanks for the reply. OK.. First.. Those cracks are all over the bottom of the hull. They aren't localized to forward or aft.. but there are more in the rear and middle areas.
You lost me at Strake... yea... not that technically hip on the small boat lingo. There are no stringers on the interior of the boat. It's just a solid fiberglass mold as far as i can tell.
"The fairing you will need to do will be the lamination edges of the strakes biax cloth, the hull sides by the spray rail and to fill the weave of the cloth." I didn't understand what you were talking about here at all. I need some edumication on it please!
Rat
Well-known member
Mojo said:
Based on those locations I would say they occurred at speed (while planing) and is either due to overpowering the hull or a weak hull, less likely but possible is overloading.
Fairing: is nothing mor than making everything glass smooth. We are familiar with smothing out of fenders during autobody repair, it is the same thing. We use a fairing compound, or make our own from Silica, to fill in the low spots on the hull; we also use it to fill in the weave on the fiberglass cloth or matt we use. Once you have applied the epoxy it will harden to the weave of the glass and be rough. Fairing fills this in so we have a glass smooth bottom and sides. More sanding...
Strakes are the "runners" on the bottom of the hull. Your hull has a Vee bow but a flat bottom, similar to a dory. On a full Vee bottom we call it the keel, but on flat bottoms we cal it/them strakes. They help stiffen the bottom of the hull and to keep it glued to the water in tight high speed turns; they also help protect the bottom when beaching as the strakes take the damage and not the bottom of the hull. My suggestion is to add two more strakes on the bottom of your hull midway between the strake you already have and the chine (where the hull bottom meets the hull sides). This will give you better performance in turns, better protection from obstructions and a much stiffer bottom so we don't have these "oil can" cracks again.
Laying the glass cloth "up to the spray rail" just means covering the bottom and up the sides to the first break in the hull. In your case it looks like you have kind of a stepped chine and I would end the glass cloth right there. It is easier to make it pretty when you end on a break then to try and feather the edges, for me anyway.
But basically you will need to smooth out (fair) any edges of the glass cloth to make nice uniform transition without bumps and bubbles and get a glass like finish on the bottom. It looks prettier and it performs better.
Realistically you can probably, with help, lay the glass one day, add the strakes the next and maybe a couple of days of fairing and sanding. Easily done in a couple of weekends with a little time after work thrown in. The epoxy curing will take the most time, and the sanding
Rat
Well-known member
Mojo
Well-known member
Ok, Thanks for the info. Now I understand. So, add a couple of strakes to the back to stiffen up the hull and glass it all up.. fill in the cloth with fairing compound, sand it all out smooth... paint... good solid boat bottom.
Thanks for the info Rat. One other question. Can i fiber over the existing paint? That stuff is on there solid.. taking it all down to bare fiber is going to be a chore if that is required.
Thanks for the info Rat. One other question. Can i fiber over the existing paint? That stuff is on there solid.. taking it all down to bare fiber is going to be a chore if that is required.
Mojo
Well-known member
Well I learned a very valuable lesson today. That cost me around $40 in materials. Fiberglass is a strait pain in the butt to work with... and trying to do one good sized sheet of it all at once is a bad idea.
But now the bottom of the boat has another coat of resin on it. Guess I'll go sand it out tommorow and try again. This time thou i'm cutting up that cloth into more manegable portions.
But now the bottom of the boat has another coat of resin on it. Guess I'll go sand it out tommorow and try again. This time thou i'm cutting up that cloth into more manegable portions.
Mojo
Well-known member
It was a bit too cold out today to do any fiberglass work. I'm waiting till monday when the temps are supposed to be up in the high sixty's and low seventy's. But I did get the new strakes for the bottom of the boat cut and sanded into shape. I think they are going to look good on there when it's all said and done.
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Rat
Well-known member
Don't worry about getting all the paint off, itf it is good resin paint, which it proly is from the factory, you should have no worries getting the new epoxy to adhere.
When working with large sections of glass cloth it is best to have a friend help; but the secret is in prepping the area. Have everything cut and ready to go it will minimize the mistakes. And don't worry, everyone blows a little time and money in learning something new, we usually call it tuition!
If you still plan on cutting the cloth into smaller pieces, allow for a three inch overlap at the seams. DO NOT stop each piece right at the edge of the other piece this will create a weak spot in the hull.
Also you will need to build fillets down those strakes to get a good radius on the glass matt so no air bubbles get it. You can use the same epoxy glue to build the fillets you use to glue down the strakes. Those strakes look perfect BTW!
Here is a pretty good article on fillets:
Fillet Tutorial
When working with large sections of glass cloth it is best to have a friend help; but the secret is in prepping the area. Have everything cut and ready to go it will minimize the mistakes. And don't worry, everyone blows a little time and money in learning something new, we usually call it tuition!
If you still plan on cutting the cloth into smaller pieces, allow for a three inch overlap at the seams. DO NOT stop each piece right at the edge of the other piece this will create a weak spot in the hull.
Also you will need to build fillets down those strakes to get a good radius on the glass matt so no air bubbles get it. You can use the same epoxy glue to build the fillets you use to glue down the strakes. Those strakes look perfect BTW!
Here is a pretty good article on fillets:
Fillet Tutorial
Mojo
Well-known member
Here's the bottom of the boat all glassed out! That was alot of work.. once i got going it wasn't too bad but about half way thru my painting hand started to cramp up.. i just had to push thru it and get it all finished up. I'm going to go back and place some more cloth along the keel probably tommorow. I have to go get myself some more resin. Fun, Fun, Fun. Seriously thou.. i'm never doing this again.
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Rat
Well-known member
Mojo said:
The way you are going you will never NEED to, that will be one tough hull! Once it dries you will be able to see a big difference in deflection just with what you have added. Good job.
Mojo
Well-known member
Got my strakes glued down and ratched in place for drying today. I also ran all over central florida but finally found a place to sell me some 6" Biax cloth in a 50 yard roll. So plan for tommorow, if it doesn't rain; is to mix up the fillet compound and get those strakes ready to be fiberglassed in.
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Mojo
Well-known member
It's been a busy morning. I got the ratchet straps taken off the new strakes and they are on that boat SOLID. Time to get to work with the fillets...
I got the epoxy mixed up and added sillica to it till i got a nice thick paste. Added it all along the rail then went back and smoothed it out with a little rounded plastic fiberglass tool i picked up at Lowes.
I had pre-cut the fiberglass tape to size and once my fillets were layed in i placed the fiberglass down and whetted it all out. I had some issues with air bubbles at the front and back. We'll see how bad it is after its all dried up. I'll give it 4-5 hours to cure then go out and cut any of the air bubbles out then lay down another layer of cloth.
I'm starting to get the hang of this fiberglass stuff.
I got the epoxy mixed up and added sillica to it till i got a nice thick paste. Added it all along the rail then went back and smoothed it out with a little rounded plastic fiberglass tool i picked up at Lowes.
I had pre-cut the fiberglass tape to size and once my fillets were layed in i placed the fiberglass down and whetted it all out. I had some issues with air bubbles at the front and back. We'll see how bad it is after its all dried up. I'll give it 4-5 hours to cure then go out and cut any of the air bubbles out then lay down another layer of cloth.
I'm starting to get the hang of this fiberglass stuff.
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Nick Jones
Well-known member
That was a great idea.
Mojo
Well-known member
I can't take credit for the idea. Rat gave told me it would be a good thing to do and I decided he was right so I ran with it.
Rat
Well-known member
Great job Mojo! When you are done you will not even be able to tell they are added and that will be one solid hull bottom. The strakes look perfect!
Mojo
Well-known member
Update time,
I got outside early today and got the second layer of fiberglass put down over the strakes and also ran a strip over the keel. Then i mixed up some sillica with some epoxy and coated the bottom of the boat again to start filling in the cloth weave. No pictures.. I figured you guys are getting tired of looking at the bottom of my boat.
I went out to gander last night and picked up some new bunks for my trailer (and a new rod & baitcaster :twisted: ). The old ones were shot to hell so I just picked up some pre-made ones. So while i was busy getting those installed Mr. UPS guy showed up with some of my stuff that was on order and low and behold it was the LED trailer light kit I had been waiting on. So this afternoon turned into Trailer day... unfortunatly I didn't get to finish wiring it up before it got dark outside.
I did get some other good news thou, there's a guy I go to church with that has a big garage I can make use of when it's time to start painting. It's detached from the house and He's going to give me a key so I can work on it without having to bother with anyone being home. SWEET.
So the plan is to finish the fiberglass work here in the back yard at my place where the dust doesn't matter then when i'm all ready for paint I'll load the boat back up on the trailer and tote it over to the garage to do some painting. I'll be leaving it there to work on the interior modifications also. Lights and power means when I start my fabrication I'll be able to work after sunset and whip this thing out.
I got outside early today and got the second layer of fiberglass put down over the strakes and also ran a strip over the keel. Then i mixed up some sillica with some epoxy and coated the bottom of the boat again to start filling in the cloth weave. No pictures.. I figured you guys are getting tired of looking at the bottom of my boat.
I went out to gander last night and picked up some new bunks for my trailer (and a new rod & baitcaster :twisted: ). The old ones were shot to hell so I just picked up some pre-made ones. So while i was busy getting those installed Mr. UPS guy showed up with some of my stuff that was on order and low and behold it was the LED trailer light kit I had been waiting on. So this afternoon turned into Trailer day... unfortunatly I didn't get to finish wiring it up before it got dark outside.
I did get some other good news thou, there's a guy I go to church with that has a big garage I can make use of when it's time to start painting. It's detached from the house and He's going to give me a key so I can work on it without having to bother with anyone being home. SWEET.
So the plan is to finish the fiberglass work here in the back yard at my place where the dust doesn't matter then when i'm all ready for paint I'll load the boat back up on the trailer and tote it over to the garage to do some painting. I'll be leaving it there to work on the interior modifications also. Lights and power means when I start my fabrication I'll be able to work after sunset and whip this thing out.
Mojo
Well-known member
Finally got back outside today and got some more work done. It rained cats and dogs Thursday and Friday so nothing got done at all, Saturday I had to go celebrate my Grandmothers 92nd Birthday, so my weekend was pretty much filled up.
Got the trailer lights all wired up and heat shrinked today. Those LED lights are awesome! Nice and bright, had to chase down a loose ground before they would come on but after i found that it was good to go.
I got about half the boat bottom sanded down smooth. If you ever have a fiberglass boat and want to redo the bottom of it you had better have a lot of time. I realized it was going to be some serious work, but I didn't know exactly how much work. I bet over the whole deal of sanding down the old paint and the new fiberglass i've gone thru 7-8 packs of 80 grit sheets. And I've still got more to go but i'm pretty confident I'll be putting on the first coat of paint before the end of the week. As long as the weather holds.
Got most of the matterials I ordered for the build in, got my new seats and all the hardware for that along with the various switches, pannels and lights. I'll stack all this crap up when I've got the space in the grarage i'm going to borrow and take a few pictures of it and get them posted as soon as possible.
Peace out Tinboaters
Got the trailer lights all wired up and heat shrinked today. Those LED lights are awesome! Nice and bright, had to chase down a loose ground before they would come on but after i found that it was good to go.
I got about half the boat bottom sanded down smooth. If you ever have a fiberglass boat and want to redo the bottom of it you had better have a lot of time. I realized it was going to be some serious work, but I didn't know exactly how much work. I bet over the whole deal of sanding down the old paint and the new fiberglass i've gone thru 7-8 packs of 80 grit sheets. And I've still got more to go but i'm pretty confident I'll be putting on the first coat of paint before the end of the week. As long as the weather holds.
Got most of the matterials I ordered for the build in, got my new seats and all the hardware for that along with the various switches, pannels and lights. I'll stack all this crap up when I've got the space in the grarage i'm going to borrow and take a few pictures of it and get them posted as soon as possible.
Peace out Tinboaters
Rat
Well-known member
Yep, fairing and sanding the hull is the most labor intensive part. But the more you put into it the better it is going to look!
bassonater
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I can't express my gratitude enough to you for your service to this country. Really enjoy seeing your progress, it reminds me of my first boat , it was a 1973 tomboy. Keep up the work an thanks!!
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