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Re: GT27 Build (Wes K)

Posted: Wed Apr 03, 2019 8:51 am
by pee wee
Great progress! I think some builders go to lengths to suspend or support themselves over the hull bottom in order to get that glassing done, it's awkward no matter how you do it. Congratulations on a big step forward!

The AT is a beautiful trail, I've done all the Georgia portion and part of North Carolina. It's argued that Georgia is the most difficult section because there is little ridge walking- it's up that mountain and down the other side. Maine has the loose rock that plays havoc with ankles and boots, and is the other contender for most difficult. The portions I've done in Virginia were nice and easy ridge walking, but it's all worth the effort and a great family experience.

Re: GT27 Build (Wes K)

Posted: Mon Apr 15, 2019 6:34 pm
by wkisting
We had a nice trip on the Appalachian Trail and made it another 15 miles, so we only have about 8 miles left to finish the entire Georgia portion. On the afternoon of our first day, we got pummeled by hail for about 45 minutes, which completely coated the mountain in white and kind of scared the girls a little. They were wet and cold, but we pressed on for another two miles to warm up, and then I managed to get a fire going--which was a miracle given how wet everything was, but as expected, it recovered their morale. Second day was beautiful and sunny, and third day was misty and overcast but not too rainy. We decided not to stay on the trail a fourth day because there were severe storms in the forecast.

Had today off, so I got some boat work done. Took about 7 hours, but I installed the four floor stringers along with frame D (#4) and several temporary spacers to get everything aligned properly. Then I epoxy-tabbed it all in place. Now I just need to spend a few evenings making fillets and laying tape to bond them permanently.
floor-stringers.jpg
I'm still thinking that I should fill the side areas with expandable two-part foam and seal those permanently, but leave the center space (~2' wide between the two inmost stringers) unfilled so that batteries or other items can be stored under the floorboards. The foam should stiffen the hull as well as provide some sound dampening and insulation.

Re: GT27 Build (Wes K)

Posted: Mon Apr 15, 2019 7:35 pm
by Fuzz
I don't think there is anything wrong with sticking some foam in the outer areas. Man it would take a bunch to foam in that whole bottom :help:

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 7:17 am
by wkisting
Wow, there's a lot of work involved with the floor. Worked for three hours last night, and only managed to get two sides of a single stringer filleted and taped! Three more to go (i.e., six more seams to fillet and tape), plus all the lateral frames yet. I underestimated how long this phase would take! Guess I'm just too eager to get the floor in so I can start the fun part of the interior layout.

Anyone have recommendations on two-part pourable foam to use for under the floor? I see it comes in different brands and also different densities. Not sure what I should be looking for exactly for optimal strength/rigidity without adding unnecessary additional weight.

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 8:50 am
by Jeff
wkisting, It is our opinion that all you need in the standard 2 LB Buoyancy Foam and not the 4 lb. The 4 lb is more about structural enforcement! A 2 gallon kit of the 2 lb will give you 8 cubic feet of foam. A 4 gallon kit is likely enough but some builders like to foam everywhere, that is up to you!! Nice build!! Jeff

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 9:39 am
by Bogieman
Jeff wrote:
Fri Apr 19, 2019 8:50 am
wkisting, It is our opinion that all you need in the standard 2 LB Buoyancy Foam and not the 4 lb. The 4 lb is more about structural enforcement! A 2 gallon kit of the 2 lb will give you 8 cubic feet of foam. A 4 gallon kit is likely enough but some builders like to foam everywhere, that is up to you!! Nice build!! Jeff
Hi Wes! The foam Jeff is recommending works great and it's super easy to use. It's the same foam I used in my build. I also poured 4 gallons :D

Your boat is looking great!

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 2:22 pm
by wkisting
Thanks for the recommendation. That's very helpful!

Jeff, you sell it through the store, yes?

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 4:06 pm
by Fuzz
You can do the math and get pretty close to what you need. Add at least 10% extra as it seems like you never get full expansion. At least I never do in my cooler weather.

Re: GT27 Build (Wes K)

Posted: Fri Apr 19, 2019 5:17 pm
by OrangeQuest
Here in Texas on a mild summer day when the temps are in the cooler 3 digits you can expect more than full expansion. Just the warmer it is the less time to mix and pour!

Re: GT27 Build (Wes K)

Posted: Mon Apr 22, 2019 12:42 pm
by wkisting
Rough estimate, I'm thinking I'll have about 66 cu. ft. to fill under the floor (excluding the 2' wide area running up the center). The 2lb. density foam is definitely cheaper because its expansion is almost double that of 4lb. foam. Anyone think there would be much/any benefit to stepping up to 4lb. density? I notice in a lot of forums, people recommend 6lb. density for structural strength, and 4lb. density for any area that will have moderate loads (e.g. a fuel tank) to support. That got me thinking: I will be pouring this under areas supporting a small fridge, a toilet, etc. The 2lb. density is generally regarded as entirely non-structural and strictly for non-load-supporting areas where you want to prevent water intrusion.

Presumably, the structure of the GT27 doesn't depend on foam, so I can see just using the 2lb. But would denser foam offer any advantage or higher durability over time? Maybe that's a moot concern for a sealed compartment.