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SOBX Little Big Boat GV15

Posted: Wed Mar 11, 2020 7:17 pm
by BrianC
I just started my GV15 build. I need a boat for back bay fishing (1-2 people), ferrying small groups (5-7) for beach days and sight seeing (protected back bay waters only), and claiming and oystering in shallow areas (~1.5’). The GV15 will live on an existing 2000 lb. capacity side lift on my dock. Given all that, the GV15 seems to be the ideal choice.

The boat will be used in Bogue sound, the area inside of Bogue inlet, estuaries behind barrier islands, brackish creeks and rivers, and the Intracoastal Waterway. While the main channels in these area are 4-15’ in depth, most area outside the channels are 3’ or less. One creek that I frequent has a ~1 mile section that about one foot deep at lowish tide if you pick the optimum route. Many areas that I fish are about that same depth at low tide. While distances aren’t that great most of the time, some days I might be traveling 20-30 miles. Again, the GV15 fits the bill.

Just one picture for today - here is the strongback up on saw horses. I'll leave it at that height and use it as a cutting table for the molds and hull panels. It will then get fixed legs for the first part of the hull build and then get castors after the flip.

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I'm hoping to get the hull completed & flipped before hurricane season hits so that I can tow it to safety should we get (another) one headed our way!

Re: SOBX Little Big Boat GV15

Posted: Wed Mar 11, 2020 8:50 pm
by Dan_Smullen
Best of luck on the new endeavor!

Re: SOBX Little Big Boat GV15

Posted: Thu Mar 12, 2020 8:07 am
by Jeff
Look forward to watching your build!!! Jeff

Re: SOBX Little Big Boat GV15

Posted: Sat Mar 14, 2020 11:06 pm
by BrianC
It always seems slow at the start. I installed tarps along the exposed side of the under-the-house build area. Hopefully, this will help keep exposed wood dry and will cut down a bit on the wind. I also installed some LED lights-on-a-string to make up for loss of ambient sunlight:

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I've drawn out all the molds onto 1/2" OSB but won't make any cuts until the hull panels and stringers are cut since those panel serve as the cutting table:

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I have the BS1088 Okoume plywood for the hull panels and stringers and will be laying those out next. I'm thinking that I will edge glue and tape the pairs of plywood sheets that are needed for the four hull panels then do the cutting afterwards. It would seem that this would minimize alignment errors that might creep in if I cut first and glued after.

Re: SOBX Little Big Boat GV15

Posted: Fri Mar 20, 2020 10:42 pm
by BrianC
After spending the last few days cleaning up my work area, I've finally started to make some more progress on the GV15. Today, I spliced two pairs of 6 mm Okoume sheets for the hull's two bottom panels.

First, I marked the area to be taped:
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Next, I pre-wet both the area to be taped as well as the plywood edges with neat epoxy. I mixed about 2 oz. of epoxy which was enough for the pre-wet and left enough for the 'glue' (epoxy + wood flour to peanut butter consistency):
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After mixing the epoxy + wood flour glue, I applied some to the edge of each panel:
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Next, the panels were pushed together and the excess 'glue' scrapped off:
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Next, I tapped with 12 oz. 6” wide biax tape which was first weighted so that I could mix the right amount of epoxy (110% of tape weight works for me):
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All the epoxy work was done using a 2” chip brush cut down a bit:
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Lastly, I used vinegar to clean the brush & cups, followed by a water rinse. For the few spots on me that always seem to get around the gloves, I used the same white vinegar pre-mixed with cheap hand lotion.
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Re: SOBX Little Big Boat GV15

Posted: Sat Mar 21, 2020 11:51 am
by piperdown
Nice work!

Re: SOBX Little Big Boat GV15

Posted: Sat Mar 21, 2020 11:59 am
by Jeff
Great start!!!! Jeff

Re: SOBX Little Big Boat GV15

Posted: Mon Mar 23, 2020 10:19 am
by BrianC
The glue up of the two pairs of 6 mm Okoume ply sheets went well except that I found out that I shouldn’t use wax paper to keep my weight bricks from sticking to the glued seam. Good thing I checked before the epoxy was fully cured or I might have had to grind them off! Going forward, I will use plastic sheeting or packing tape.

The first step was to double and triple check all my measurements. BS1088 ply wood is pricy so measure three times, cut once.
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After that I stacked the glued up pairs on top of the other, aligned the edge that won’t be cut, and screwed them together. I placed the screws on the frame lines so the screw holes well serve to make the frame positions on the second panel. Next, I hammered in a finishing nail offset a bit from each marked point so that the drawn line goes through the marked points. I had a 18’ long slice that was trimmed from a PVC foam corner-board that makes an ideal batten for tracing the cut lines between the nails:
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Here is the hull bottom panel all marked out:
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I used the stitch hole marking tool I made for the SK14 to add stitch holes after cutting. It is just a strip of ply with two finishing nails hammer through just enough to mark the ply. You just place the first nail in the last marked point, align the edge of the ply strip near the second nail with the panel, and then press to mark the next hole. The second hull bottom section is underneath so the holes along the keel will match perfectly:
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Here are the finished pair of bottom hull panels:
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after sliding the finished panels underneath the cutting board foam sheets, I covered the glued splice area with packing taping - this should work much better than wax paper:6127

I also made up a couple of drip cups for my epoxy jugs:
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Lastly, I placed another pair of panels on the cutting table. Here they are all glued up:
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Next up, cutting the hull side panels and gluing up the last pair of ply sheets for the stringers.

Re: SOBX Little Big Boat GV15

Posted: Mon Mar 23, 2020 10:17 pm
by BrianC
Today I cut the pair of hull side panels. Since these are cut from the same pair of glued up sheets of 6 mm plywood, I first cut them in half lengthwise and then stacked the two pieces. The stacked pieces were held together with screws while I did the cut:
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Next, I glued up the two 12 mm sheets that will be marked up and cut for stringers tomorrow:
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I’m now down to one sheet: the 18 mm for the transom:
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A few more days of this & I'll be ready to start stitching!

Re: SOBX Little Big Boat GV15

Posted: Tue Mar 24, 2020 11:10 pm
by BrianC
Today I marked out and cut the four stringers (2 inside, 2 outside) out of 9 mm Okoume. As with the hull panels, I first stacked two pre-glued panels so that I would get identical pairs.

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One issue that I ran into was that some of the lines traced by the batten didn’t result in fair curves. Pressing the batten down against all the finish nail reference points resulted in unexpected 'wiggle' in the traced line. In these photos, the arrows point to ‘correct' line:

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I think I fixed the issue by using the batten to trace between just 3-4 points at at time and always having a straight line between the points as a reference. I recall that several other builders of the GV15 had issues with hook of the hull bottom panels — I wonder if this could be part of the problem?

The stringers aren't doubled as they are in many other designs, and they seem a bit flimsy. I'm going to tape the second side and give them a coat of neat epoxy to strengthen them a bit.