PDA

View Full Version : Boat Repair and Hull Structural Rebuilding For Beginers - Trash to Flash



Gordon02
01-11-2018, 01:34 AM
I wanted to test the waters and see if there is interest in learning and discussing How To Repair a Boat's Various Hull Components. I see this particular content is included in this thread's title, but don't see many home-made projects shared.

Many of us have thought about buying an older boat. For some, it would be their first. For others, it could be one that is just too darn cool to let someone else take it home. One of the Glastron GT150's from 1970's is and has been on my bucket list for years now (Live and Let Die.....yea, me too!), but it's down on that list. I do have the 1976 90 horse Chrysler sitting on a stand just waiting.

Don't trust what you see when looking at a used boat. Neglect and exposure to the elements can do catastrophic damage to the hull, stringers, and transom with no visible signs. Even the better made boats won't last exposed. Have a look at the Norris Craft rebuild below and you'll see what poorly drilled screw holes and silicone can do to a "well made" boat.

My first boat 40 years ago was a steal at $500. That price got me a very nice, fiberglass 14 footer with Johnson outboard, trolling motor, and trailer that it's owner had driven the boat up onto a concrete ramp after several hours of heavy drinking. 8" of the keel was crushed and left a hole that you could stick your fingers through. I've never been afraid to tackle fiberglass repairs since. There are many bargains out there. Once they have transom failure or other obvious rot/de-lamination, they become "almost free".

If this thread gets a lot of views and if readers want to know and will share more, I'll be happy to share more photos and procedural steps. I'll also explain when, where, and why Epoxy, Polyester, 3M 5200, 1708 Biaxial Glass, non-wovens, Cabisil, wood flour, and many other "good stuff" products. Let's see - Gordon

My neighbor's Norris Craft - purchased for $1,500 last year, we found that several holes were drilled over the years completely through the transom for sonar, speedometer, and other electronics. All of them below the bilge line where water should never be and then incorrectly sealed with silicone. We had to completely tearout and rebuild the bilge area. We made our stringers, flooring, and flotation boxes out of hand-laid composites and aluminum to support the fuel tank. After tabbing layers of 1708 with laminating epoxy, we assembled all of the components using epoxy.

396665
396666
396667
396668
396669
396670
396671
396672
396674
396673
396664

Gordon02
01-11-2018, 02:11 AM
This is my 14 foot 1982 Randall Craft rebuild from 2016. Call this one a robbery, (yes I paid too much for a boat it's seller knew was bad). The owner had put plywood over the rot and painted it to cover just good enough for the eBay listing. I drove 4 hours and picked it up in the pouring rain, so I missed the deceit. A few days later, and I'm cutting the flooring apart and deciding to re-design the boat to a stick-steer for river and protected waters fishing - perfect for old guys like me that want to sit in one spot and never have to move. I removed 305 lbs of rotted wood and foam.

I use lauan for patterning. It's cheap and easy to shape/trim. Those are easily transferred to White Oak and Marine plywood. I also use it to make my laminate panels after application of mold release. The wood used in the new stringers is White Oak (closed cell and the wood of ship builders for hundreds of years). I use CPES (clear penetrating epoxy sealer) to seal all sides and edges of any/all wood used. The flooring and side panels are all hand-laid 100% composite panels that are epoxied into place and then marine closed cell foam used for support. 4 lb foam (90psi) is used in the floor, and areas needing support. 2 lb foam is used in the bow and sides.

396675
396676
396677
396678
396679
396680
396681
396682
396682
396683
396684
396685
396686
396687
396688
396689
396690
396691

Gordon02
01-11-2018, 02:39 AM
This is my current project - a $400 purchase of a 1976 Arrowglass 15 footer that I'm rebuilding and turning into another "stick-steer", but this one will replace my smaller green Randall Craft that I've just sold. I wanted a bigger river boat and this one will have a Johnson 70 horse looper - one of my favorite engines. Again, White Oak and marine plywood sealed in CPES are used along with 1708 bi axial glass and epoxy. 45 holes were drilled and every cavity filled with 4 lbs structural marine foam (closed cell) with 90 psi compression strength. The brown circles are epoxy and wood flour, CPES again covers the entire surface, Epoxy tabbing of 1708 was applied, the livewell and seat were glassed-in (no screws), sanded, then non-woven 8 ounce fiberglass Mat is applied with Polyester Resin for a smooth, durable flooring base that will be finished in a Light Silver TuffCoat. The cap/top was rebuilt with structural glass/White Oak beams along with new marine plywood sealed with CPES. The cap/top and hull joint was then filled with epoxy for a true 1-piece boat. The next guy will not get this one apart! This project should be done by March, but lots to do yet such as finishing the cap/top, motor well, and glove box. I also have to paint and re-assemble the outboard which is in 100's of pieces.

396692
396693
396694
396695
396696
396697
396698
396699
396700
396701
396702
396703
396704
396705
396706
396707
396708
396709
396710

W2F a V-King
01-11-2018, 06:31 AM
Wow..These are neat projects and should get some looks and comments and questions. :thumbsup:

Might get more exposure in the "Fiberglass and Composites Discussion" section. Not sure though.

W2F a V-King
01-11-2018, 06:39 AM
This is my current project - a $400 purchase of a 1976 Arrowglass 15 footer that I'm rebuilding and turning into another "stick-steer", but this one will replace my smaller green Randall Craft that I've just sold. I wanted a bigger river boat and this one will have a Johnson 70 horse looper - one of my favorite engines. Again, White Oak and marine plywood sealed in CPES are used along with 1708 bi axial glass and epoxy. 45 holes were drilled and every cavity filled with 4 lbs structural marine foam (closed cell) with 90 psi compression strength. The brown circles are epoxy and wood flour, CPES again covers the entire surface, Epoxy tabbing of 1708 was applied, the livewell and seat were glassed-in (no screws), sanded, then non-woven 8 ounce fiberglass Mat is applied with Polyester Resin for a smooth, durable flooring base that will be finished in a Light Silver TuffCoat. The cap/top was rebuilt with structural glass/White Oak beams along with new marine plywood sealed with CPES. The cap/top and hull joint was then filled with epoxy for a true 1-piece boat. The next guy will not get this one apart! This project should be done by March, but lots to do yet such as finishing the cap/top, motor well, and glove box. I also have to paint and re-assemble the outboard which is in 100's of pieces.



I used the exact same epoxy in my current project. Actually my first go with epoxy and will not likely go back to polyester.

XstreamVking
01-11-2018, 07:27 AM
Poly over epoxy on floor? Unless i'm reading that wrong. The foam WILL become waterlogged over time. But, nice workmanship used and will last for a long time. We all build them the way we want to, using our own methods..

Gordon02
01-11-2018, 08:46 AM
If we use good practice and the correct materials, there should not be any water intrusion. Much like the Boston Whalers, Rangers, and the above mentioned Norris Craft - this red Arrowglass has a "bilge line" that should never get wet below said line. The internal shape of this hull is weird and very different than the green Randall Craft. It has deep areas in the bow area at the keel and the tri-hull shape which also has deep recesses that would hold water forever if I tried to create a "wet keel" flooring system. In the green Randall Craft, I used white foam board to create multiple 1" channels along the keel and then blocks of the same board to create voids across the transom. All of the white foam board was then removed after the 4 lb marine foam was poured/cured providing immediate water drainage to the bilge area that allows complete draining during storage and by the bilge pump.

The stringers in this red boat are shaped to fit the hull along the flat areas of the boat and then continuously bonded to 100% of the hull bow to transom using epoxy "peanut butter" and multiple layers of 1708 and epoxy laminate. The marine plywood is sealed top, bottom, and edges with CPES then applied onto the white oak stringers with a thorough bed of epoxy and 1708 biaxial glass then attached with brass screws ooozing epoxy and weighted for a solid, 1-piece bond. The flooring was then locked-in with repetitive layers of 1708 biaxial glass and epoxy at seams and sides. I have faith that this will remain water-tight if 3M's 5200 is used on every screw and fastener going into and through the hull.

Half of the way into the project I decided that I did not want carpet for this fishing boat. The non-woven Mat gives a very smooth, nice surface. The problem with Mat is that it can only be used with Polyester Resin. The MEK hardener used to activate the Polyester also dissolves the binder holding the strands/fibers in the Mat. Epoxy won't work with Mat or dissolve it's binder, so I had to sand all of the epoxy joints and surfaces so the Mat could be applied. Very little preparation will be needed for the Tuff-Coat non-skid coating that will be applied to the floor and sides. This flooring covering includes 2 coats of their special epoxy and then 2 thick coats of Tuff-Coat rubberized non-skid. I wanted an open, flat surfaced layout with a prominent, water-proof bilge box and water-tight interior that can be washed/hosed clean after a day of good fishing. No carpet in this one. Gordon

XstreamVking
01-11-2018, 09:11 AM
I would only offer 1 suggestion. Stay away from the poly epoxy combo with the poly over the epoxy. You could use a cloth glass or an epoxy compatible matt on the floor. Epoxy sticks to everything, nothing sticks to epoxy. Even if it is ground previously.

Gordon02
01-11-2018, 10:27 AM
Here are some better views of this boat's hull/keel shape. I could not figure out how to incorporate a wet keel drainage system so I filled the entire bilge line with structural, 4 lb marine foam and then seal-out all possible sources of water intrusion. I'll let someone else see if I've succeeded in 20 years...

396737
396739

Gordon02
01-11-2018, 10:52 AM
This US Composites marine foam is amazing stuff. First, it's something like 98.5% closed cell so water doesn't have a place to go. Second, the 4 lb foam has a compression strength of 90 psi, the 8 lb foam has a whopping cs of 250 psi. Mixed in equal parts, you quickly blend and then pour it into cavities. The liquid state last for about 40 seconds while it crawls into corners and crevices, then it expands in all directions. We've learned to hold pressure by hand for a short time while it pushes upward in the corners, then release so it completely fills each cavity. The tops are cut and then filled with epoxy peanut butter (epoxy and wood flour) as you see in the earlier photos. I really like the 4 lb foam for floors and then 2 lb in the bow, gunwales, and cavities specifically made for flotation and no support is needed (2 lb foam has 40 psi cs).

396740

W2F a V-King
01-11-2018, 12:21 PM
US Composites does have epoxy compatible CSM and so is their 1708.

I have always been leery of the mix n pour foams due to the fact that the old boats I have restored that had foam was always water logged to some degree. And yes if not vented properly when applied it can lift a floor, push a bulkhead out of shape.... Maybe the fish oil type I used (the few times I had to lock a belly tank in place) were different back then (some 25-30 years ago).

Looks like a cool hull on the last one posted...triangle pad!

Gordon02
01-11-2018, 01:12 PM
Quote "Looks like a cool hull on the last one posted...triangle pad!"

Yea, who makes a pad like that? I bet my modified Promax wouldn't put this boat on that pad - God forbid anyone having to try and drive it there! I think the mold designer saw one on another boat somewhere and thought his boat should have a "pad" too. The keel/bow will always be in the water just waiting to bowsteer and hook sharply just before violently tossing it's occupants into the lake! This thing doesn't have a single lifting strake, so it's not going anywhere quickly. The original 70 horse Johnson (old power head rated motor) will be doing good to push it into the low 30's. My Allison can outrun all of the fish I've ever pursued, but I'm betting this one will find more fish per trip than it's stablemate. Gordon

noli
01-11-2018, 01:46 PM
.


awesome thread...very interested in all of your work!





.