http://ephemerisle.org/index.php?action=history&feed=atom&title=Platform_3.0 2026-05-09T13:46:11Z Revision history for this page on the wiki MediaWiki 1.34.1 http://ephemerisle.org/index.php?title=Platform_3.0&diff=1801&oldid=prev 2015-03-08T21:02:55Z

<p>Created page with &quot; = Version 1.0 (2009) = Heavily built 4x8&#039; plywood sections built of 2x6? 2x8? lumber, with cross pieces, and 55 gallon drums. Sections were bolted together. == Pluses == ?...&quot;</p> <p><b>New page</b></p><div><br /> = Version 1.0 (2009) =<br /> <br /> Heavily built 4x8' plywood sections built of 2x6? 2x8? lumber, with<br /> cross pieces, and 55 gallon drums. Sections were bolted together.<br /> <br /> == Pluses ==<br /> <br /> ??<br /> <br /> == Minuses ==<br /> <br /> * Stresses were enough to bend the bolts.<br /> <br /> * Someone must swim under the platform to screw together the bolts.<br /> <br /> * Very heavy.<br /> <br /> * Drums must be sealed ahead of time for silicon to set.<br /> <br /> * It's a *big pain in the ass* to screw the lids on correctly.<br /> <br /> = Version 2.0 (2011?) =<br /> <br /> Built of overlapping sheets of plywood with 27 gallon bins for<br /> floatation.<br /> <br /> == Pluses ==<br /> <br /> * The biggest advantage by far to this design is that is stacks into a very small space for transport and storage.<br /> <br /> == Minuses ==<br /> <br /> * It takes quite a long time and effort to assemble.<br /> <br /> * The deck is too flexible. Some screws pulled out when a crowd was dancing. And the center submerged when the platform was full of people.<br /> <br /> * Also, the bins fill with water when submerged.<br /> <br /> * Consensus seems to be that the design limit was reached at 20'x24'.<br /> <br /> = DIY 1.0 (2011) =<br /> <br /> 8'x8' frame with plywood deck and 55 gallon drums for floatation.<br /> <br /> == Pluses ==<br /> <br /> * Simple to build and very strong.<br /> <br /> == Minuses ==<br /> <br /> * Design is limited to 8'x8'. No current design for expanding it.<br /> <br /> * 8'x8' platform is a bit unwieldy to move around.<br /> <br /> * Drums must be sealed ahead of time for silicon to set.<br /> <br /> * It's a *big pain in the ass* to screw the lids on correctly.<br /> <br /> = Version 3.0 (design) =<br /> <br /> = Deck =<br /> <br /> * Probably built in sections so that it can be easily transported.<br /> <br /> 4'x8' are easier to move around and will fit into the existing<br /> construction space.<br /> <br /> 8'x8' - Fewer points where we have to connect sections would be far<br /> better.<br /> <br /> * How to connect the sections?<br /> <br /> Getting this right is probably the biggest hurdle. There will be<br /> tremendous stresses on these joints.<br /> <br /> = Floatation = <br /> <br /> * Simple wooden V's or canoes to create pontoons.<br /> <br /> Even the simplest ones will take time and effort to build, plus probably<br /> require maintenance every couple of years.<br /> <br /> Only real advantage may be that with the right design they could be<br /> stackable.<br /> <br /> * PVC pontoons<br /> <br /> Very simple to construct. Probably shouldn't require any maintenance.<br /> Unknown how durable 12&quot;+ pipe is.<br /> <br /> * EPS Foam<br /> <br /> One of the cheaper options and easiest to put together. This is why most<br /> docks seem to use it. Should be easy to work with. We can order any size<br /> and easily cut it to size/shape.<br /> <br /> * 55 gallon drums<br /> <br /> Free. But they've been known to leak if not sealed right, and they're<br /> big, heavy, and rather hard to move around.<br /> <br /> * Notes on pontoon alternatives<br /> <br /> (followup to discussion Sunday 19 Aug 2012 @ oakland boat hackers): it<br /> looks like a glassed foam shell is going to be noticeably cheaper than<br /> solid foam for floats; I did some checking on prices and calculation of<br /> material requirements. Details below. -dave w<br /> <br /> Tradeoffs in material cost for pontoon float construction<br /> <br /> Assume 2 ft. diameter cylindrical pontoon float x 8 ft. lengths<br /> (probably representative of material requirements for tapered ends.)<br /> <br /> Solid foam: volume of cylinder - pi \* R\^2 \* L<br /> <br /> R = 1 ft. L = 8 ft. Volume = 8 \* pi = about 25 ft\^3<br /> <br /> Glassed foam shell: area of cylindrical surface<br /> <br /> pi \* D \* L = 16 \* pi = about 50 sq. ft.<br /> <br /> Assume 1 layer of 9 oz./sq.yd. (1 oz./sq.ft.) fiberglass fabric +<br /> <br /> 1 oz./sq. ft. mixed epoxy required. Foam shell thickness 1 in.<br /> <br /> So 50 sq. ft. shell surface will need 50/12 = 4.167 cu. ft. of foam,<br /> about 50 oz. of epoxy, and 50 sq. ft. of fabric.<br /> <br /> Rough comparison (representative material costs - see detail below)<br /> Solid foam:<br /> <br /> 25 cu. ft. foam x \$10/cu. ft. = \$250<br /> <br /> Glassed shell:<br /> <br /> 4.2 cu. ft. foam x \$10/cu. ft. = \$42<br /> <br /> 50 oz. epoxy x \$0.80/oz. = \$40<br /> <br /> 50 sq. ft. cloth x \$0.80/sq. ft = \$40<br /> <br /> total \$120<br /> <br /> Material price notes: Epoxy: about \$1/oz. in quart lots; down to<br /> \$0.60-0.70/oz. in gallon+ quantities. (TAP Marine Grade is about \$120<br /> for 160 oz. (1 gal/resin + 1 qt. hardener); 40 oz. for \~\$40.)<br /> <br /> Glass cloth: \$0.62-\$0.78/sq. yd. (Aircraft Spruce/TAP princes) for<br /> style \#7500 (9.6 oz/sq.yd.); range of weights and styles available<br /> <br /> Foam: Aircraft Spruce has blue small-cell extruded foam 2 lb/cu. ft. : 4<br /> in. thick x 2 x 4 ft. sheet (2.67 cu. ft.) for \$58 (\$22/cu. ft.)<br /> <br /> Universal Foam has same size white expanded (bead) foam 2lb/cu. ft. for<br /> \$25 (\$9.4/cu. ft.) - probably our best bet for thick foam.<br /> <br /> Home Depot has pink extruded foam 2 in. x 4 ft. x 8 ft. (5.33/cu. ft.)<br /> for \$29 (\$5.4/cu. ft.) - this stuff is the cheapest (not surprising, a<br /> lot of it gets sold for building insulation) but I don't know if any<br /> thickness over 2 in. is available.</div>

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