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1978 Viking resto-mod

Posted: Mar 09, 2019 3:16 pm
by tnelson77
Seeing as this forum is the go to place for all things Hydrostream I figure I should post a build thread of what I'm doing to my Viking.

This boat has been in my family since 1981 when my dad and uncle bought it for a ski boat. It was used and well kept for many, many years. But like all of these boats even with the best of care the core, floor, and transom was rotten. Can't blame it after 30 years. On its last day in the water it came over a large wake and cracked the hull beneath the foot well. It started taking on water pretty quick so to the launch and on the trailer it went.

This project started in about 2005 when my older brother and cousin began the tear down process. They removed the rotten floor, center stringers, and most the core from the dash back. The deck and hull was then split up to the dash board to be able to remove the transom without cutting out the splash well. A few patches were laid on the hull in some damaged spots and a new transom was installed. At this point money ran out. We were just kids at the time, I was a senior in high school. So the project was pushed outside and sat for the next 12 years.

I began agin this fall. I purchased a new tandem axle trailer and set the boat on that. It was very flimsy with out a core in it. I built a very supportive cradle to hold the hull during its rebuild. The cradle is a 1/2" plywood and 2x6's I also have a 36" piece of aluminum to keep the pad dead flat.

I decided to completely remove the deck from the hull to make the work easier. With the deck removed the rest of the core, the outer stringers, and transom was removed agin. The transom that had been installed was already rotten. To be fair it was never fully finished years ago. I began by grinding and sanding the entire hull to prep for new material. Once all holes and damage to the hull was completed with multiple layers of 1.5oz CSM a full layer of 1708 was laid over the entire bottom of the hull.

The new transom is two pieces of 3/4" marine grade plywood laminated together with a layer of CSM. The transom was laid in and clamped to the hull with a layer of CSM and a wet lay up of resin. I built a set of giant Jorgenson style clamps out of 2x4's and threaded rod. It was then tabbed in with three layers of overlapping 1708 and two full layers of 1708.

I choose 1/2" balsa for the core material for its strength properties. The core was fitted and bedded into a wet lay up of CSM after getting two heavy coats of resin and allowed to soak in. Shingles were used to provide some even weight to bed the core.

This is where I'm at now. Long first post since I'm a ways into the build already, but I'll post updates more frequently along the way.

Re: 1978 Viking resto-mod

Posted: Mar 11, 2019 8:15 am
by Hippie459MN
Very nice! Glad to see this rebuild here. Been following it on S&F and it coming along nice! :up:

Re: 1978 Viking resto-mod

Posted: Mar 20, 2019 7:56 pm
by Shortblock
:up: Mann that's a sweet boat cradle you built to put your boat in.....If you can post some if the steps it took to build it!!!We could stand to all learn from that...Thanks I would like to build one or buy yours....Lol

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Re: 1978 Viking resto-mod

Posted: Mar 21, 2019 8:39 pm
by tnelson77
Shortblock wrote: Mar 20, 2019 7:56 pm :up: Mann that's a sweet boat cradle you built to put your boat in.....If you can post some if the steps it took to build it!!!We could stand to all learn from that...Thanks I would like to build one or buy yours....Lol

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I would be happy to sell mine. It will be coming out of the cradle within the next six weeks or so. I'd let it go for what I have into it, which is about $350. Local pick up would be best. I'm near Minneapolis, MN.

Any way, here's a few pictures of the cradle build. I flipped the hull upside down and got it sitting level side to side. Then marked a board every inch across the width of the hull. I set this board above the hull on some saw horses and took a measurement down to the hull and transferred the measurement to the plywood. I made sure to mark the chines and edges of the pad etc. Play connect the dots on the plywood and cut it out with a jig saw. I had to fit and trim each board a few times to get a fit I was happy with. I have a piece of plywood about every 2'. Once they were cut I started screwing them together with braces in between. Once all the plywood was fit I used a scrap 2x6" to mark where they would sit on the chines to fully support those. Cut the openings to clear the 2x6"s and the aluminum plate for the flat area of the pad. I set the 2x6"s in and secured them with some scrap blocks to the plywood. Once the main 2x6"s supports where in I just added a bunch more bracing to everything. I then trimmed the bottom edge of the plywood to get it sitting at a good height. Once I flipped it and set the hull in it I noticed the height was a bit off so I added the 4x4" "legs" to keep it more square and get the hull at a better height. I also added some more plywood near the seam of the hull and deck to fit exactly so the hull wouldn't distort when the deck was removed.

Re: 1978 Viking resto-mod

Posted: Mar 21, 2019 9:03 pm
by Shortblock
I wish I was a bit closer I think that'll be close enough to get me there rebuilding a boat it really needs the extra support so you don't build one with a hook bottom thank you for the quick response others will appreciate it as well by the way good luck on your rebuild.....Stream-on-

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Re: 1978 Viking resto-mod

Posted: Mar 30, 2019 3:38 pm
by tnelson77
Core is completed and covered with a full layer of 1708. I used a mixture of cabosil/milled fibers to make a paste to fill the edge of the core to give the glass a smooth transition.

I built my stringers out of two pieces of 1/4" plywood laminated together. They seem to be very strong but I think this was way overkill. If I were to do this over agin I would skip this step and just use 1/2".

I laid a 4" strip of 1708 on top of the core and on the transom where the stringers will sit. I used a marine adhesive to secure the stringers to the hull rather than a Cabosil/milled fiber paste, taking that advice from the folks at Express Composites. It seemed to work pretty well, it was a lot easier that's for sure. I'll still have to mix up some resin paste to make a nice fillet along the edges.

I cut some notches in plywood to hold the outer stringers in place and keep their shape as the adhesive set up. For the center two stringers I just cut some scrap boards and picked up some cheap Harbor Freight clamps to hold them the proper distance apart.

Re: 1978 Viking resto-mod

Posted: Mar 30, 2019 3:52 pm
by Hippie459MN
Very nice! I like the jig for the outer stringers. Its looking great. :up:

Re: 1978 Viking resto-mod

Posted: Apr 01, 2019 2:20 pm
by alaskastreamin
It's good to see nice clean work. Looks like you might have done this a time or two.

You may already know this but worth mentioning.

You might consider thinning slightly some resin and coating the plywood. WE call it "priming" the wood. This does two things.

1. It soaks into the wood fibers and seals them and the lay-up resin will bond to this and adhere into the cells of the wood fibers.
2. without priming, the wood will draw the resin out of your lay-up creating a drier than optimum laminate.

Re: 1978 Viking resto-mod

Posted: Apr 01, 2019 3:22 pm
by tnelson77
alaskastreamin wrote: Apr 01, 2019 2:20 pm It's good to see nice clean work. Looks like you might have done this a time or two.

You may already know this but worth mentioning.

You might consider thinning slightly some resin and coating the plywood. WE call it "priming" the wood. This does two things.

1. It soaks into the wood fibers and seals them and the lay-up resin will bond to this and adhere into the cells of the wood fibers.
2. without priming, the wood will draw the resin out of your lay-up creating a drier than optimum laminate.
Thank you! This is my first time working with fiberglass. But probably won't be my last. I've spent a decade as a welder in the food processing industry so I've always been very meticulous with my work.

This priming you speak of, are you coating the wood and letting it cure and then scuffing it before your layup? Or just coating it before laying on your cloth?

Would acetone be suitable for thinning the resin? I'm using GP polyester.

So far I've been putting a heavy coat of resin on the wood and letting it sit for a while before laying the cloth and then adding my resin to the cloth.
Always open to advice since this is my first time. Thanks!

Re: 1978 Viking resto-mod

Posted: Apr 01, 2019 5:16 pm
by alaskastreamin
I learned what I know from our local boat builder. He makes his molds then the boats (26'-36'). He knows fiberglass WAY deeper than you or I could ever imagine.

I explained some of what I know in this 4 part article. http://hydrostream.org/Topic.htm.

Your initial contact with your fabrics is called your "mechanical" bond. This is where I was told to go a rough as 16 grit. 24 will work if you can't get the 16. Resin rich is brittle and resin starved is limber. So getting the right "wet-out" is important. This is why I used core-bond putty for all my bonding. Thick or thin, the putty has the same strength. Regardless, your way does work with very acceptable results.

Thinning the resin to penetrate into the wood fibers is best w/ styrene. Styrene is the natural thinner in poly resin. Yes, acetone will thin the resin however it dilutes the molecules and you lose some strength. Also if acetone is used with gelcoat, you may see chalking soon due to the molecular dilution.

I go with double the catalyst when priming. As soon as it gels up, you can do your lay-up. No need to slop it on, you just want it to penetrate into the fibers and not have a shiny glaze. 10% thinner is MAX. A cap of styrene in a quart of resin really thins it FYI. You usually have up to 36 hours for a "chemical" bond so no scuffing needed in this time period.

Hope this helps some.

You're doing a great job!! Documenting the process should bring top $$ if you sell in the future.