Dinghy hull weights

Originally posted by Sam.Spoons I have, today, more accurately weighed my Topper Spice (346, built by White Formula in, I think, 1998) and, all up, it weighs 152kg (+/- 2kg I'd say). That is 134kg for the hull and mast, with rigging, jib and kite onboard and 18kg for the other bits (mainsail, boom/mainsheet tackle daggerboard and rudder assembly). A disappointing 20kg more than I hoped. I guess my 'not entirely watertight' hull will have absorbed a little H2O over the years but I can't believe 20 litres.  I also weighed my mate's L3k and arrived at 116kg (just to rub salt into the wound.....). Might weigh a 'tin rig' Phantom tomorrow if my other mate will risk the embarrassment, and possibly a Topaz Trez. Then I plan to find a L@ser to weigh.......

Blimy those boats are heavy, a 505 has a sailing weight of 127.4kg, and that includes everything apart from the sails.

Originally posted by Sam.Spoons The 505's 127.4 'sailing weight (hull, fittings, foils and rig but no sails) is pretty impressive for a 50 year old design but exotic materials (CF, kevlar, epoxy etc) are commonly used in their construction. Given all of that the RS400 at 129 kg is not so heavy, it's a bit shorter than a 505 but is built in relatively conventional materials (vinylester resin, not epoxy and not much, if any CF).

This year my 21 year old 505 was weighed at 1kg overweight, and it still carries 2kg of lead, so a full reweigh would put it minimum weight. It is built from polyester resin with end grain balsa sandwich in high stress areas, it also has an alloy boom, the only carbon is the twin poles and tiller, there isn't anything exotic in the hull.

Tha heaviest phantom, polyester rather than a wooden one, weighed in the last 15 years at the nationals I think was approx 14kgs overweight,making it 75kgs without rig.

Edited by maxibuddah - 26 Aug 16 at 8:13am

Originally posted by RS400atC I am surprised there's no carbon at all in a mid 90s 505, not even around the mast/bulkhead/chainplate area? Was it around the end of the 80s Parker had their 'type 25' 5-oh? and that development was going on in all the rival builders too.

I can assure you there is no carbon in this particular 505 hull, built by Kyrewood, they did build some hulls around that time in carbon, but they continued to offer both options so there was a lower priced hull and the carbon one. However even without carbon it is still very stiff, certainly in comparison to similar age boats from other builders. Some of the build is is purely glass, and in the high stress areas end grain balsa sandwich.
I guess during the 80's 90's as you say there were several 505 builders, all trying to get an edge on their rivals, but I guess my point, given what this thread is about, is that not all boats, even those of more "basic" construction will take up water. Perhaps the secret lies in the build process as well as the care taken with the boat over the years?

Somebody suggested earlier in the thread that a boat may have taken up 20kg of water, really?, that would be aprox 20 litres, is that realistic in a 4-5m long dinghy, it may be of course if there is a lot of timber under the fibreglass as that would hold water very easily if it got in and have difficulty getting rid of it, I have certainly heard horror stories in some classes.

Certainly weighing boats should not be a major problem and could save a lot of trouble. At Phantom nationals in the past we used to simply place the boat on a bench scale similar to these https://www.ourweigh.co.uk/bench-scales/WS12000AAZAAAA.html?gclid=Cj0KEQjw0f-9BRCF9-D60_n4rKcBEiQAnXW4-5yvE2Bo0GpirmGIdU0qeeUtDeBiIisSLrWWVYJFYzUaAp7m8P8HAQ  once you knew where the balance point was it was simple and took very little time, I have also seen the same used with a custom made V or U shaped pad on top which you can rest any hull on. For the sake of £80 a set of scales would be a good investment.



Edited by Roger - 26 Aug 16 at 10:49am