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oceansky

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Everything posted by oceansky

  1. When we were first looking at Paulownia, the first thing we did was had it tested through the Queensland Testing Services for its mechanical properties and also a comparitive test against WRC. Paulownia was far lighter in its density (260kg/m^3 compared the WRC 384kg/m^3) and as far as its mechanical properties were concerned, not that much less than WRC. The reason we had it tested was so that when we design to classification society standards (commercial) we've got the data sheet for the said timber. There are various species of Paulownia, some heavier than others. The species grown here in Australia are typically the lightweight species, yet I have heard that in the states, its the heavier species which is grown. (Hence the little difference in weights) All that aside, as a timber for planking, I much prefer Paulownia. Top Stuff
  2. Actually it's less. WRC is typically around 380 kg/m^3 whereas Paulownia is 260 kg/m^3. Great material to work with !!
  3. G'day Ken, As a boat building material, it's great ! We use it a lot in all our strip plank designs Highly recommend it regards Mark
  4. Thanks Par, Typical BS1088 ply as you mention above is similiar in price to ours here in Oz. However, when it comes to Lloyds Okoume ply, its way more than what your paying !! 4mm - $83 per sheet 6mm - $126 9mm - $147 12mm - $198 15mm - $220 18mm - $243 25mm - $330 And this doesn't include transport charges
  5. Curious Par, How much is a sheet of 6mm Lloyds plywood worth in the States ?
  6. I couldn't agree with you more mate. To tell you the truth, after testing it and calculating the bending strength and Modulus of Elasticity of the said ply, I was pretty disappointed actually. Especially when considering the price of the plywood against other plys. But yes... that is a story I don't want to get involved with here
  7. I wish I could agree with you Par, but unfortunatly I've already found out through one of our clients and also through our own testing that this doesn't hold. One of our clients who was especially chasing a light weight dinghy, asked if I could recalculate one of our designs using the suppliers figures. Using 460kg/m^3, the boat should have come out to approx 40 kg. So, he rang the supplier and purchased the plywood based on the suppliers figures for weight. After building the boat, I asked him to weigh it and to our surprise it came out to 65 kg. The builder went over every part of the boat, trying to figure out where the extra 25 kg came from. So, I opened up my weights and moments spreadsheet, I recalculated the boat using 600 kg/m^3 plywood density and the spreadsheet result was 64.5 kg boat weight. Having some samples of this Lloyds plywood, I then did a density test and yes, the result was ...600kg/m^3. Further testing resulted in 6mm plywood = 600 kg/m^3 9mm plywood = 540 kg/m^3 Overall, through my own research, testing and use of Lloyds Special Service Craft standard, I could say a lot on this subject, particulary in regards to this "approved" plywood and all it's so called marketing, but I feel that I must leave it all for obvious reasons... unsaid. I couldn't agree with you more mate
  8. G'day Chris, I recently conducted comparitive tests of various species of plywood and about to conduct tests on plywood with various types of fibreglass. In regards to the plywood itself test, I was actually surprised with the results, particulary the advertised densitys compared with "real" results. Also, in regards to the bending strength and Modulus of Elasticity (or stiffness), here to was a huge difference between the various species of plywood. I hope over the Xmas break to finalise my testing and maybe publishing the results here, or on our website regards Mark
  9. G'day Chris, I use plastic corner quad that is sold at the Bunnings Hardware store. Its around 3m in length and sells for around $8 a length.
  10. Just curious Scott, how often did they audit.? Here in Oz, the EWA audit the plywood companies every 6 months
  11. Funny you should say that Scott. Last week I rang "Engineer Woods Australia" also known as Australian Plywoods Assoc. and asked why Gabbon plywood is not allowed under AS2272 standard for marine plywood. They emailed back with the response" Not sufficiently durable for exterior use and difficult to impregnate with preservatives"
  12. G'day drednought, talking with the boys from the Sydney game boat club, they HATE those ball valves. They're always giving trouble. Crikey, bet the boat was put together by someone new on the job or ...maybe the transom was laid up on a Monday or Friday
  13. Funny you shoud mention that Sam, anoteher Cruise Craft (7m) also sank of Townsville 3 weeks ago. http://www.cruisecraft.com.au/showroom/walkarounds/cruisecraft_outsider_685.php
  14. "Lloyd's doesn't certify plywood any more, so the BS 1088 standard is a purely voluntary classification now" Par, I've questioned this myself about Lloyds not certifying plywood anymore, but I can't find any mention of this anywhere on the web. Where did you find this? regards Mark
  15. G'day Marcus, Thanks for enquirying about the Edge Tracker. In regards to the vertical height, the distance from the sole to the side deck (vertical height) for Edgetracker 426 is 595mm or 1ft -11.5in. The Edge tacker 487 (16ft) is 2ft 1.25in ( 641mm) The edge tracker 548 (18ft) is 2ft 4in (711mm) To build the edgetracker 426 should take approx 2 weeks to build, however this would not be full time as a lot of your time, your just sitting around waiting for the epoxy to cure before beginning the next stage. As an example, we took 2 weeks to build the Mushulu 14, working on average 3-4 hours per day. Building the edge Tracker is pretty easy (like all our designs) as all the components or parts are given with measurements and they're also nested onto plywood sheets to help save on wastage Hope this helps
  16. G'day kleptonite, If your looking for a large load carrying vessel that can carry a large family in comfort, the Gulf Explorer 16 may be the right boat for you. We actually have a couple of GE16's about to commence construction, whereby the builders do have large family's to cater for. If you look at the specifications on both designs, the GE 16 is 7ft- 2" ( 2.18m) wide, whereas the XR457 is 6ft-8in ( 2.02m). The GE16 can also carry a greater load when calculated under the standards. In regards the the curvature in the topsides plate in the forward sections, the GE16 does have quite a lot of flare. It's just in plywood sheet form instead of curving as per the RipTide series. Can the designs be stretched?. Not really, as it effects so many other design facets which people in general don't realize. Then they run into all sorts of construction problems down the track. In other words, stretching the hull is easy enough, but the internals become the problem, which can lead to the boat becoming "unbalanced". This is why with most of my designs I try to bring out various sizes to cater for people who want larger of smaller versions of the said designs. As far as family activites are concerned in regards to swimming/ diving and, generally climbing on and off the boat whilst out and about, here once again the GE16 is the better option, as it also includes a swimming platform at the rear enabling easy access aboard, making it a more family oriented design in regards to water sports. As far as seating within the GE16 design itself is concerned, although we show pedastal seats for a avid fisherman, we're also at looking at including bench seats within as an option, whilst still retaining the centre console in it's present location. This is an option I'm presently drawing also into the new Edge Tracker Series, as shown on our website. Hope this helps Mark
  17. G'day Kleptonite, Sorry for not replying sooner, but I had trouble logging in. At the present moment, No it can't as the temporary frames would need to be drawn to suit, plus also a stem piece as well. I'm am however, looking at bringing the design out for foam core construction in the near future. None really in regards to the Gulf Explorer 16. If the design had "flair" in the bow, then strip plank would be the better choice as opposed to plywood cold molding as strip planking is a far quicker build without the need for all the timber stringers etc required for cold molded boats. However, being a flat panel style of boat, its quicker again to build from sheet plywood of foam. This is a question most asked of all designs and is a tough one to answer. The reason being, it depends on the final weight, the load that the boat will carry that day, the outboard Horsepower/ gearbox ratio/ prop pitch and diameter and, finally whether its a 2 or 4 stroke outboard and also "slip". All these can vary it's overall performance. To get into it here, would require a full page of an explanation. However, not taking all this into account, you should be looking a 33 kts (38 mph ) with a 60 Hp and an average prop pitch of 13 " and 37 kts (43 mph) with a 75 Hp with an average prop pitch of 15 ". These figures are based on a standard factory 3- blade prop and carrying a typical load of a family unit of 4 on board with all their safety equipment and personal stores/ fishing gear/ 75 litres of fuel (19.7 US Gallons) / anchoring gear and the like, for a total displacement of 861 kg (1898 lbs ) Hope this helps Mark
  18. Not really. Walk into any business/ office stationary supply shop and you'll find packets of them.
  19. G'day Par, Hope all is well your way. Glda to see your on here Kleptonite, I totally agree with Par in regards to his comments. Our final fairing boards are just made from plywood with a couple of handles. Simple. We use our inline sander for all the major sanding and the "torture boards" for the final "touch-ups".
  20. G'day kleptonite, Fairing boards between 2- 3ft work best when working on your own. If you've got someone to give a hand, go for a 4 ft'er. I personally use the straight line sanders. Hook it up to your compresser and away you go. Make's fairing real quick and does a great job. I rang up my nephew who's a panel beater and he said it's one of the tools they also use. It does a great job of fairing and it's quick. It's also what Graham used to fair his SportzMaster 19 ! It's costs AUS $90 http://messing-about...portzmaster-19/
  21. Here's another tip that can save some time that I use when cutting fibreglass on a flat surface such as cutting tapes or some glass for a specific shape. Use a rotary cutter instead of scissors The ones I use are Supercraft brand (about $8-10 bucks each) and you can get them at the hardware. I use them to cut cloths up to 1150 triaxial and they do it easily.
  22. Hi all, I was having a chat to Mark today about painting and he asked if I could put something up here about how we finish our boats. Basically there are two ways to go here - a single pack system i.e. enamels or a 2 pack system. I start both systems the same way. In the single pack range, I use Altex paints as they are reasonable priced, easy to use have great backup technical support and best of all only use turps for clean up and thinning. Once you have finished fairing, a multipurpose primer is used (what a lot of people call "grey primer" ) followed by 3 coats of undercoat then 2-3 topcoats. The Altex 2 pack range is also pretty user friendly and their Elite 321 brushing polyurethane can give an equivalent finish to a spray job. Here's what I do. After I have sealed the boat with a couple of coats of epoxy resin, I give the boat a sand to knock down any epoxy lumps and to provide a key for any fillers. Large holes to fill ( shouldn't be any) and any tape edge transitions are filled with epoxy resin and filler powder ( I use WEST resin and 410 Microlight filler.) Once this is sanded back I spray the entire boat with Altex no 2 High build surfacer which is essentially epoxy fairing compound that you can spray on (it can also be trowelled or brushed). International and Awlgrip also make similar products. The beauty of this product is that it's hardness is consistent. It is very difficult to mix up a batch of epoxy resin and filler to the precise consistency of the previous batch and this can lead to differences in hardness of the fillers. If you have a hard patch of filler (resin rich) next to a less hard, (filler powder rich) mix and then try to sand them both the softer area will get scrubbed out first and you will chase your tail trying to get the boat fair. The Altex #2 is beautiful to sand and fills fibreglass weave really well to leave a lovely fair surface. Once the #2 is sanded (most is sanded off) it needs to be sealed so there is no "shadowing" of the bog into the topcoats. Here you can use the grey primer for single pack systems or the Altex #3 undercoat for a two pack job. With either a single or 2 pack system, we apply 3 coats of undercoat. Normally 3 coats is enough but if after sanding the hull back I have a lot of "grey areas" showing through, I will add another coat or two to provide an even white surface. This helps lighter topcoat colours achieve and even colour with minimal coats. When applying the undercoat, I generally spray as it achieves a really even surface but the same can be achieved using the roll and tip method. Try and apply the undercoat as smooth as possible as it will save lots of sanding. Finally after all the prep it is time for the topcoats. The thing to remember is that your topcoats will not hide an unfair surface or fill holes. Once the undercoat is sanded and the boat is vaccumed off, I give the boat a couple of wipe downs with a silicon and wax remover. This is available from hardware stores, super cheap auto, repco etc. This ensures that the hull is clean and there is no contamination left on the hull that could affect the topcoat. Next step is to tack rag the hull to remove any final dust and then paint. Sounds like a lot of work but it is worth it. When applying topcoats, you can brush or spray. The roll and tip method works well for both single and two pack systems but if you are going to do it with two pack, ensure that you have the right converter for brushing which allows the brush marks to flow out. I generally use high density foam rollers (Uni Pro brand) and high density foam brushes (Jen Poly Brand)when rolling and tipping. With the two pack system, you can also get a gloss reducer or matting agent to de-gloss the paint. There is nothing worse that having the inside of your boat in full gloss as the glare is terrible. I normally use a satin to semi gloss on the inside of the boat and a semi gloss on the outside. Wooden boats generally don't look good with that wet look high gloss in my opinion. Anyway that's what we do down here. I had to laugh earlier this year when I had a boat at the Wooden Boat festival in Hobart. A bloke came up to our ply daysailer, rapped his knuckles on the hull and proudly announced to his mate - "I told you it was fibreglass" . Goes to show you can get a good finish on your timber boat after all. Hope this might help some of you through the painting game. Regards, Andrew Denman www.denmanmarine.com.au
  23. Hello all, Iv'e been using some new fairing boards lately, and I have to say that they are terrific tool to use. Not only are they easy to use, they produce a great finish in half the time spent using the 3M boards. They are called Flexi-cat tools, here's a picture of them.
  24. When building, the question most often asked is, what size fillet do I use when tabbing with glass tape? So I thought I'd put this together. The depth or throat of fillets should be equal to the thickness of the thickest piece of plywood being fastened and should extend outward from the centreline of the joint 1.5 to 2 times it's thickness. Here I've provided fillet blade radius for various thicknesses in plywood. As an example: 6mm plywood will require a minimum fillet blade radius of 14mm ( diameter of 28mm- refer diagram above) Naturally this is to be applied to both sides of the joint to be fastened, and tabbing to be applied ie 200 gm cloth or Double Bias. I hope this helps
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