1978 Hourston Glascraft Restoration

[Fritz]

Good info on what to expect tackling one of these old gems, thanks for sharing!

December 27, 2021 - short video just checking out my stringers. They were not bedded in place.

The stringers in these boats were not bedded with mastic compounds. They were dropped right on the hull and for reasons that were pioneered by Bertram and Hourston in FRP construction on runabouts.
Okay,
If you cream a dead head with your hull at 30 + mph something has to budge. The way they engineered this was from the data they collected with composite structures during WW2, a lot from the PT Boats.
The way it works is almost as if a micro pocket is formed under the stringer. Instead of your active stringer acting like “hard spot” in the hull and busting the fibreglass open adjacent to it, the micro-pocket compresses and allows the laminate to flex on the tapered tabbing. As we know tapered structures dissipate stresses well.
Bedding in Sikaflex, PL (Not a fan), 3M 5200 or West systems epoxy is totally fine, because they flex. If you are leaving some of the original tabbing to act as a channel to drop the stringer in I would recommend using sikaflex (just my opinion). If you burn off the old laminate right down to the hull then use west systems method they outline in their repair manual, because as it was mentioned earlier the fibreglass resins don’t like to stick to polyurethane sealant adhesives and you’ll have a bugger trying to do your fillets.

These are just recommendations. My biggest recommendation is to read the product information guides and fiberglass repair literature and make your own decisions.

I also hope nobody out there in TV land thinks I’m trying to steer anyone from using modern materials. Just be aware of the drastic changes required in your laminate schedules.

Things are only as strong as what you attach them to. If you overbuild something it merely becomes an anvil for breaking the rest of the structure over.

Seriously everyone, enjoy your projects

 

[Fritz]

The stringers in these boats were not bedded with mastic compounds. They were dropped right on the hull and for reasons that were pioneered by Bertram and Hourston in FRP construction on runabouts.
Okay,
If you cream a dead head with your hull at 30 + mph something has to budge. The way they engineered this was from the data they collected with composite structures during WW2, a lot from the PT Boats.
The way it works is almost as if a micro pocket is formed under the stringer. Instead of your active stringer acting like “hard spot” in the hull and busting the fibreglass open adjacent to it, the micro-pocket compresses and allows the laminate to flex on the tapered tabbing. As we know tapered structures dissipate stresses well.
Bedding in Sikaflex, PL (Not a fan), 3M 5200 or West systems epoxy is totally fine, because they flex. If you are leaving some of the original tabbing to act as a channel to drop the stringer in I would recommend using sikaflex (just my opinion). If you burn off the old laminate right down to the hull then use west systems method they outline in their repair manual, because as it was mentioned earlier the fibreglass resins don’t like to stick to polyurethane sealant adhesives and you’ll have a bugger trying to do your fillets.

These are just recommendations. My biggest recommendation is to read the product information guides and fiberglass repair literature and make your own decisions.

I also hope nobody out there in TV land thinks I’m trying to steer anyone from using modern materials. Just be aware of the drastic changes required in your laminate schedules.

Things are only as strong as what you attach them to. If you overbuild something it merely becomes an anvil for breaking the rest of the structure over.

Seriously everyone, enjoy your projects

Thanks for taking the time to post videos.

 

[Iworkupnorth]

The stringers in these boats were not bedded with mastic compounds. They were dropped right on the hull and for reasons that were pioneered by Bertram and Hourston in FRP construction on runabouts.
Okay,
If you cream a dead head with your hull at 30 + mph something has to budge. The way they engineered this was from the data they collected with composite structures during WW2, a lot from the PT Boats.
The way it works is almost as if a micro pocket is formed under the stringer. Instead of your active stringer acting like “hard spot” in the hull and busting the fibreglass open adjacent to it, the micro-pocket compresses and allows the laminate to flex on the tapered tabbing. As we know tapered structures dissipate stresses well.
Bedding in Sikaflex, PL (Not a fan), 3M 5200 or West systems epoxy is totally fine, because they flex. If you are leaving some of the original tabbing to act as a channel to drop the stringer in I would recommend using sikaflex (just my opinion). If you burn off the old laminate right down to the hull then use west systems method they outline in their repair manual, because as it was mentioned earlier the fibreglass resins don’t like to stick to polyurethane sealant adhesives and you’ll have a bugger trying to do your fillets.

These are just recommendations. My biggest recommendation is to read the product information guides and fiberglass repair literature and make your own decisions.

I also hope nobody out there in TV land thinks I’m trying to steer anyone from using modern materials. Just be aware of the drastic changes required in your laminate schedules.

Things are only as strong as what you attach them to. If you overbuild something it merely becomes an anvil for breaking the rest of the structure over.

Seriously everyone, enjoy your projects

Thank you for the info I love it. I'm not planning on reinventing the wheel. whatever they originally did worked perfect for this boat. it's 43 years old and the hull is solid. stringers are in great shape. the transom had a bit of rot but this could of easily lasted a few more years before a rebuild was needed from what I see. Hourston did an amazing job.

 

[coopsie]

love the headlights. Did you add those?

They were factory lights that was a 1979 Hourston I own a 81 now

 

[Iworkupnorth]

January 8, 2022 - finally got a break in the weather and took out one stringer it came out easily in one piece so now I have a good game plan. What does everyone think about taking all the stringers out, do you think the hull will warp at all? there's 12 points of contact with all the wheels on the trailer and their not to far apart so I think I will be fine. Especially with a glascraft because I don't remember the thickness of the hull but it is much heavier duty than other glass hulls. Anywho here's just a quick video, was very rewarding seeing it come out in one shot. I plan on removing the rest all in one solid piece.

 

[daddystoy]

When I redid the stringers on my boat I built a support with 2x4s that ran longitudinal with the length of the hull to provide continuous support to the hull for when the stringers are removed. This way it should prevent any deflection while you are working in the boat.

 

[Iworkupnorth]

January 9, 2022 - Relized I needed to reassess and get those gunnels out and that front cross member plywood piece (not sure what it's called).

 

[Iworkupnorth]

January 23rd, 2022 - quick video just to show one full stringer being removed in 1 piece.

 

[Fritz]

January 23rd, 2022 - quick video just to show one full stringer being removed in 1 piece.

Hope you kept those as templates. Out of curiosity how is the quality of the Doug Fir? My inboard stringers were relatively clear straight vertical(ish) edge grain but my outboard stringers had a lot of inclusions and knots.
My only other thought is to bleach the hell out of the bathtub before putting any new stuff in. I also used an electric tea kettle to poor boiling water in slots then shop vac’d it out. Any mold spores left will start the composting process over (faster).
My stringers were wet but not rotten. It’s amazing how well Doug Fir holds up especially after 40 years.
Incidentally your video brings back memories of a 3 month nightmare lol

 

[Darkwingduck]

Welcome to this blog about the process of restoring this beautiful classic 18.5 foot boat. I welcome open discussion on products and others previous experience. Idle hands are the devils workshop. That will not be the case this winter on this amazing island. Cheers to everyone who has undertaken a project similar to this. I look forward to any constructive input. Start date November 1st, 2021.

Cool I was just going through forums to get some knowledge about transom rebuild and came across you're post here's what I'm going to be working on 1976 hourston 18 foot hardtop I look forward to reading you're posts