20' Hourston Autopsy and Resurection

[Fritz]

Well,
I've been meaning to do a write-up but most of the time I am busy working after kiddie bedtimes so here goes.
On October 30 of last year I did a full gut on a 20' Hourston. I have had some good advice from this forum and I hope maybe someone else on here can extract something useful on another Hourston build in hopefully a small way of paying back. I hope you enjoy the notes and photos.

Kindest Regards,

Fritz

 

[Fritz]

Well,
I've been meaning to do a write-up but most of the time I am busy working after kiddie bedtimes so here goes.
On October 30 of last year I did a full gut on a 20' Hourston. I have had some good advice from this forum and I hope maybe someone else on here
can extract something useful on another Hourston build in hopefully a small way of paying back. I hope you enjoy the notes and photos.

Kindest Regards,

Fritz

The resurrection photos,
The silver colour in some of the construction photos is West Systems 422 barrier coat. I didn't want to wrack the hull so the outboard stringers were done as the very last step and I utilized them for ensuring good geometry between the batwing bulkheads, inboard stringers and my very flat floor. Honestly I did nothing but copy exactly what Hourston did as far as composite lay-ups and thickness. The big change was using epoxy instead of polyester for the water resistance and secondary bond properties. The transom was originally a sheet of 1/2, a sheet of 3/4 and a half sheet of 5/8. I used the table in DNV (Det Norsk Veritas) with HP calculations that unfortunately cut off at 90 kw but used some simple ratio math to extract the increase in thickness to 2-1/4"of DF Marine plywood and 7 lay-ups of 1708 Biax and in essence copied the transom in the factory podded 20'.
The gentleman who is currently building my pod is doing an exceptional job in my opinion and I will post some more notes at it's completion.

Good Night Folks!

 

[Corey_lax]

Can you post jpg photos? People will be hesitant to open zip files

 

[Fritz]

Can you post jpg photos? People will be hesitant to open zip files

See what I can do tomorrow, honestly my JPEG photos weren't that big but the forum won't except it.

 

[adrian1991]

Very nice work
Since I took the time to download might as well make it so everyone dosnt have to either

 

[adrian1991]

.

 

[adrian1991]

Approximately can you give us your total amount of matieral (cloth,resin, cabisol plywood) by chance? Trying to get an idea of what I need for mine
Gonna pick up in Edmonton on way back from work and save on the taxxxx

 

[Fritz]

Very nice work
Since I took the time to download might as well make it so everyone dosnt have to either

Thanks dude it was late,
I will give you a materials list later tonight

 

[Fritz]

Approximately can you give us your total amount of matieral (cloth,resin, cabisol plywood) by chance? Trying to get an idea of what I need for mine
Gonna pick up in Edmonton on way back from work and save on the taxxxx

-16 yards 1708 biax
-10 gallons of West Systems epoxy with slow hardener (Inboard stringers, outboard stringers and transom)
- An ice cream pail of colloidal silica and West 403 ( I think?)
- 3 sheets of 3/4” DF marine plywood and 3 sheets of 3/4” G1S exterior DF plywood (Hourston used factory grade DF) (floor, transom, step down, rod pocket bulkheads)
- 3 gallons of vinylester gel coat (so far)
-The floor and step down was done with 2 lay-ups of 1.5 csm and I can’t remember how much.
- The floor was tabbed in with two layups of 1708 biax 8” tapes (the tape underneath was trimmed to seven inches)
- 11 tubes of sikaflex for bedding stringers and sealing the floor down (I bought a case)
- The stringers were made from 18’ spar clear timbers that were left over from a wooden sailboat project.

 

[Fritz]

-16 yards 1708 biax
-10 gallons of West Systems epoxy with slow hardener (Inboard stringers, outboard stringers and transom)
- An ice cream pail of colloidal silica and West 403 ( I think?)
- 3 sheets of 3/4” DF marine plywood and 3 sheets of 3/4” G1S exterior DF plywood (Hourston used factory grade DF) (floor, transom, step down, rod pocket bulkheads)
- 3 gallons of vinylester gel coat (so far)
-The floor and step down was done with 2 lay-ups of 1.5 csm and I can’t remember how much.
- The floor was tabbed in with two layups of 1708 biax 8” tapes (the tape underneath was trimmed to seven inches)
- 11 tubes of sikaflex for bedding stringers and sealing the floor down (I bought a case)
- The stringers were made from 18’ spar clear timbers that were left over from a wooden sailboat project.

Oh!
And a few yards of 1.4oz fiberglass cloth that used for the epoxy laminate on the bottom side of the floor and stepdown

 

[Fritz]

I also can’t reiterate enough how important it was to gut the step-down. There was never any drainage and when I popped a 2” holesaw hole in it, it was completely full of trapped water. I pulled four full 5 gallon shop vac loads worth of water out of the step!