# 13 Riverhawk- a few fiberglass ?'s



## bw77 (Mar 17, 2009)

Hi, I'm new to microskiff.com. I've been lurking for a while but haven't posted much. I recently bought a 13' Riverhawk thats in pretty good shape but I'd like to do some reinforcing and repair work to it. From what I can tell the boat has little wood in it, except for the transom which is in good shape. My point is there seems to be a lack of places to mount things to.  I can't really tell if the bench seats have wood in them at all but the glass seems to thin to just screw stuff into. I'd like to glass in some plywood to the backs of the seats to mount rod holders and a fire extinguisher. Also I will be adding a bow mount trolling motor and would like to mount a battery tray to the floor  in the bow. I've done some reading and it seems like epoxy resin is the way to go but what about the cloth? The boat has the chopped mat type cloth on the interior, should I just use that? Woven roving seems like it would be too smooth and not match. There are also a couple of repair patches I would like to redo eventually before I repaint her. Any advise would be appreciated.  Pics to follow   Thanks


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## B.Lee (Apr 29, 2008)

I would imagine the bench seats do not have any wood backing in them, they are likely foam blocks glassed into the hull for level flotation pruposes. Mounting anything substantial to them might not be the best idea.

the best option you might have is to add the mounting pad outside of the bench, by glueing a wood pad on, then laying some glass cloth over the top. I say cloth because I would recommend epoxy over polyester or vinylester resins, but that is my new personal preference.

If you use epoxy, stay away from the chopped strand mat materials. they are bound together with a light resin that relies on the styrene in polyester resin to break it down. Epoxies don't have this styrene, and will produce a weaker laminate. Chopped strand mat is generally structurally weaker than cloth whatever the resin you choose.


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## bw77 (Mar 17, 2009)

I'd like to mount a battery tray up front on the floor









This bench seat on the left side is bubbled up on top and flexes in with little hand pressure. Should I cut the bubbled part out or just lay glass over it to strengthen it?


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## bw77 (Mar 17, 2009)

> I would imagine the bench seats do not have any wood backing in them, they are likely foam blocks glassed into the hull for level flotation pruposes.  Mounting anything substantial to them might not be the best idea.
> 
> the best option you might have is to add the mounting pad outside of the bench, by glueing a wood pad on, then laying some glass cloth over the top.  I say cloth because I would recommend epoxy over polyester or vinylester resins, but that is my new personal preference.
> 
> If you use epoxy, stay away from the chopped strand mat materials.  they are bound together with a light resin that relies on the styrene in polyester resin to break it down.  Epoxies don't have this styrene, and will produce a weaker laminate.  Chopped strand mat is generally structurally weaker than cloth whatever the resin you choose.


Thanks for the reply.The only reason I was thinking strand mat was to match the texture of the rest of the boat, so it wouldn't look patched up.I will eventually repaint this boat inside and out. I guess strength is more important than looks though. 

Any suggestions on plywood types and cloth weight?


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## bw77 (Mar 17, 2009)

I also have one cracked area to repair where the aluminum gunnel support attaches. Ant suggestions?


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## bw77 (Mar 17, 2009)

Heres a pic of my home made jack plate I made. I will be running a 4hp Yamaha 2 stroke. The boat moves along pretty good but doesn't like to plane with just me in it. It runs better w/ 2 people because it planes out. I'm going to have to make some trim tabs for it too.


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## B.Lee (Apr 29, 2008)

You can always add back the chopped mat texture after the repair or addition if you use cloth. By cutting up a small bit of cloth into strands, and scattering them onto the outermost layer of cloth or even into wet resin after the cloth laminate has cured, you will end up with a similar texture, just not utilizing the mat material.

There is nothing wrong with using polyester resin and mat though, I've used it for years, and almost every boat built today uses polyester or vinylester resins. That's not to say they are the best by eny means, but are less expensive. They don't make for as good a glue material as epoxy though.


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## bw77 (Mar 17, 2009)

The main reason I was going to go epoxy was I've seen too many bad repair jobs with polyester resin. It seems like over time it likes to chip off. I would use polyester if I thought it would make for a good lasting repair, I just don't have enough experience glassing to know. Is epoxy that much more expensive?


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## B.Lee (Apr 29, 2008)

Epoxy is roughly $100/gallon, some more, some less. Polyester is $25-30/gallon. 

Most polyester resin repairs fail because of poor surface prep. Applying polyester resin on to properly repaired polyester laminates is perfectly fine.

That being said, I would much rather work with epoxy resin. It's nearly odorless, wets out clear, and is really a joy to work with. It does just what you want it to do for you. 

Cured epoxy resin is waterproof. Cured polyester resin is not, it will absorb water over time and delaminate. This might be another reason you see failed repairs with polyester resin. If not covered with gelcoat or a good waterproof paint, moisture absorbed will cause the delamination, or flaking off of the repair area.

As for your crack repair, that's relatively easy one, here's a highlight 

http://www.westsystem.com/ss/repairing-fiberglass-laminates/


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## topnative2 (Feb 22, 2009)

give riverhawk a call and ask for Paul----he will be able to answer ur questions---been there for yrs
riverhawkboats.com

k


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## bw77 (Mar 17, 2009)

Wow, thats pretty expensive. I may end up just using polyester since I'm going to be painting the inside with a good floor paint anyway, that should seal up the glass.

Any suggestions on types of plywood for the seat supports and mounting pads? Also what is the best way to make templates?


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## B.Lee (Apr 29, 2008)

Cardboard works good for templates, you can also use scrap plywood to play with different designs, shapes, etc. 

Epoxy is more expensive, but having worked with both, I'd spend the money. 

The wood depends on what you want to use it for really. A base to mount a seat pedestal too, you could use 1/2 B/C ply from a big box store with no problem. 

Here's another advantage to epoxy over polyester resins. Epoxy will actually penetrate the wood fibers, providing a vastly superior structural bond to it, and water proofing the wood at the same time. Polyester resin will mechanically bond to the wood surface only. It really depends how strong and how long you want it to last. 

The project needs to fit your budget too. Only being able to finish 1/2 of it doesn't do you any good.


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## Brett (Jul 16, 2008)

Plywood for seat supports and backing pads...
try pressure treated plywood, you know they'll end up wet.

http://www.naturalhandyman.com/iip/infxtra/infpre.html

Cardboard and tape for templates.


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## bw77 (Mar 17, 2009)

I'm trying not to spend too much on this boat, it fishes great as is I just want to make some mods and a repair or two. I just have to watch how far I go. I don't want to get too carried away with work inside and then painting inside and out, by the time I get done I could buy a new 13' Gheenoe hull for what i put into it.


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## TIGERMC (Feb 25, 2008)

I have a Riverhawk 15' original. The previous owner towed it without a transom saver and caused some damage. I used the standard fiberglass kit from Advanced Auto Parts and it worked great. I like the looks of your jack plate (please make me one).  The seats have no wood in them only foam. I used toggle bolts for the seats, after the factory fasteners failed. I have built a homemade trolling motor mount for the front (looks like a battering ram). I will send you some pictures.

TMc


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## bw77 (Mar 17, 2009)

> I have a Riverhawk 15' original. The previous owner towed it without a transom saver and caused some damage. I used the standard fiberglass kit from Advanced Auto Parts and it worked great. I like the looks of your jack plate (please make me one).  The seats have no wood in them only foam. I used toggle bolts for the seats, after the factory fasteners failed. I have built a homemade trolling motor mount for the front (looks like a battering ram). I will send you some pictures.
> 
> TMc


Thanks for the info. The jack plate is pretty simple to make but a little time consuming and has to be fit to the particular boat it's being built for. I am getting ready to build my own trim tabs this weekend, we'll see how that goes, I'll post some pics. I too am building my own trolling motor mount, when I get my trolling motor. I'm actually going to use a single piece of 2" angled aluminum left over from my jack plate build.

The seat on my boat was installed with toggle bolts too but I took it out. I will be mounting a cooler just forward of my rear bench for my seat. The boat doesn't like to plane with just me in it so i gotta mo some weight forward.

Now I just have to glass some wood into this boat so I can mount some stuff.


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## B.Lee (Apr 29, 2008)

I had a low budget idea for you to try out the epoxy, but not make a big investment.

The bateau.com guys offer a sample kit for $25 that would be plenty to do a small repair or small project like adding a seat base. That way you can see how easy and enjoyable it is working with epoxy, get a portion of your project done, and not invest a bunch of money in the boat. 

Incs glass cloth, wood flour, cups, stir sticks, and epoxy, all in one.










http://boatbuildercentral.com/proddetail.php?prod=E_try


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## bw77 (Mar 17, 2009)

> I had a low budget idea for you to try out the epoxy, but not make a big investment.
> 
> The bateau.com guys offer a sample kit for $25 that would be plenty to do a small repair or small project like adding a seat base.  That way you can see how easy and enjoyable it is working with epoxy, get a portion of your project done, and not invest a bunch of money in the boat.
> 
> ...


It's not that I don't think the epoxy is worth the $$, from what I've read it's great stuff. It's not a matter of whether I'll like using it or not, It's just deciding if I want to go elaborate and use the epoxy or go simple and cheap with the poly. I'm not restoring a boat, just reinforcing it and installing some mounting pads. If I decide to spend the $$ I'll just order enough to do everything. 

I saw this kit and was wondering if it would be enough to glass in plywood on the seat tops, a battery mounting pad, and a few small pads to screw stuff down to.I'm not sure how far this stuff goes:
http://boatbuildercentral.com/proddetail.php?prod=E_kit_3qt


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## B.Lee (Apr 29, 2008)

Take a look at my project in teh bragging spot forum, The Sawdust Skiff. All the work I've done so far has used about 3 qts.

A little bit goes a long way in my experience.


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## bw77 (Mar 17, 2009)

Your skiff is awesome man, is that a kit? That will really be something to be proud of when your done, being able to say you built your own boat!


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## B.Lee (Apr 29, 2008)

No kit, just a design of what I wanted her to look like, a little help and inspiration from Brett on his Grass Slipper build, and a lot of research on bulding techniques, materials, etc. Thanks for the compliments, she's coming together nicely.


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## kuzus (Apr 23, 2009)

Polyester resin and chop strand mat is fine for what you want to do. I would use marine grade plywood. Don't use plain pressure treated wood from the hardware store. You won't get a good bond because the wood will still be wet. If you want an easy way to add mounting pads, you could just use some Superbond epoxy putty on the bottom of plywood and paint the plywood. It wouldn't last forever, but it would be much quicker than glassing over the wood. You could seal the wood with some penetrating epoxy if you wanted. Polyester resin and mat should be fine for your repair. Grind out the crack and put mat over it. Use a lightweight putty (Bondo) on the ouside to fair the repair in.


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