1981 Aquasport 170 rebuild in Sweden

[dburr]

Lars as bad as you've been bit by the bug, keep the Big Boss happy! She may let you think otherwise, but she is the CFO and Operations manager of the project and if you get out of square on your time management she may impose heavy penalties!       !!

[larsli68]

Yes, you are both right. Rick, I probably jinxed it when I said May or June... Ain't mama happy ain't nobody happy. Today a Christmas day drive and enjoy the sunshine and the 1/4" of snow that fell last night.
No shoveling snow at least, and the boat is in a nice warm and dry shop! And I will be there tomorrow morning at 7AM!

[larsli68]

Finally Friday and 5 hours in the shop. Finished glassing the transom sides. Prepared the table with gel coat to be able to start with the floor tomorrow. I also prepared
a fiberglass strip to cover the tops of my stringers. I got quite a lot done today. Managed to take a couple of pictures too. Forgot to take a picture of the gelcoated table. Will do that tomorrow.

[larsli68]

Laminated the floor today. Also did some cleanup on the transom. Prepared the stringers for fiber glassing tomorrow.
A good day. Feels great to have the floor laminated! The Seacast pour will hopefully happen on Tuesday or Wednesday.

[RickK]

Nice job Lars.    Real nice to have the tables and area to do this.

[larsli68]

It is unbelievable to get this opportunity. I'm very grateful. I'm also learning a lot from an retired guy that works extra at the place.
Stringers today and more... Getting the floor laminated yesterday felt really great.

[larsli68]

Glassed my stringers yesterday. It is 6:15 AM here and I'm preparing to go to "work" on the boat.

[RickK]

Are you going to foam the stringers?

[larsli68]

Are you going to foam the stringers?

I don't think so. They are now strengthen with 3 layers of 600g/m2 fiberglass. Do you think I have to?
They are strong and don't budge when I stand on them.

[RickK]

At this point it is more for flotation.  Are you planning filling the outsides of the stringers with foam (like it was originally)?  You said it was going to stay in the water, right?  Might be a good thing.   If it was going to live on a trailer and when out on the water you were in it, you knew it was safe and would not sink (of course unless you hit a submerged "something").
I foamed my stringers just in case.  And I am not planning on foaming the outsides of my stringers.  Boat is living on a trailer.  It took 1.5 gals of part A and B to do the stringers.
My $.02

[gran398]

You guys may consider doing what we did and lay block foam outside the stringers. Inexpensive, adds flotation, and deadens hull slap.

[larsli68]

At this point it is more for flotation.  Are you planning filling the outsides of the stringers with foam (like it was originally)?  You said it was going to stay in the water, right?  Might be a good thing.   If it was going to live on a trailer and when out on the water you were in it, you knew it was safe and would not sink (of course unless you hit a submerged "something").
I foamed my stringers just in case.  And I am not planning on foaming the outsides of my stringers.  Boat is living on a trailer.  It took 1.5 gals of part A and B to do the stringers.
My $.02

I might foam the stringers, but the guy at the shop being my mentor thinks it's not necessary... I wouldn't mind but my boat will be in less than 2 feet of water at my dock.
I also plan to use two bilge pumps. One with a sensor always on and one that I can start with a button on my panel.
Today I glassed the underside of my hatch covers with that 600g/M2 fiberglass and added a 1/2 inch divinycell core to the laminate. I will finish them tomorrow.
I also plan to fix the new gas tank tomorrow, and hopefully do the Seacast tomorrow! It will be a long and exciting day!

[RickK]

Just more piece of mind than anything - If the stringers are stout you could probably get away without it since the foam does not add structure.

[larsli68]

Poured the transom today! It went really well.
I have to admit it feels like a million bucks to have this job behind me. Thanks to everyone in this forum that has given advice and support.
Thanks also to Jeff in Michigan who spent almost an hour on the phone with me giving great advice.
I also glassed the hatch covers, fitted a duct for the engine controls.

[Georgie]

Just more piece of mind than anything - If the stringers are stout you could probably get away without it since the foam does not add structure

 This is not true, Rick.  I don't typically like to make contradictory "call out" posts, and that's not my intent here, but this is a critical detail.  :|  While the trapezoidal stringers do have their own geometric strength, the foam inside is structural because it greatly reduces "compressibility" of the fiberglass and thereby helps them retain their shape and prevent buckling in the case of impact or a really bad wave.

This journal article briefly mentions the increased load capability for foam filled structures:  https://books.google.com/books?id=5YkMGtdsVuwC&pg=PA1017&lpg=PA1017&dq=hollow+vs+foam+filled+stringers+strength&source=bl&ots=Az2bm5P282&sig=EoYwmTDdSkYysvRLwEn-3Dc31kk&hl=en&sa=X&ei=g7GiVJ3AE4KvggT7oYPQDA&ved=0CB4Q6AEwAA#v=onepage&q=hollow%20vs%20foam%20filled%20stringers%20strength&f=false  

Perhaps remember the surfboard analogy mentioned a couple years back on one or more rebuild threads?...or an alternative analogy - would you ever mount an engine to a two inch thick but hollow transom? (yes I know the forces being applied differ, but the priniciple is the same)  

Lars, the foam in the stringers actually does not help with buoyancy unless the airlock within the stringer itself is breached and the boat is already taking on water, but it is assuredly critical to maximize the engineered strength of the build.   I strongly recommend you not skip this step.