Hey peoples, on the site here where its got roberts lotts boat in the making, can someone please tell me what was the weight of the boat when he finished? i noticed he used 3mm ply, im going off the plans and im building mine out of 4mm ply, and im just curious about the weight so i know if i have to take some weight out, at the moment i have one hull with glassed keel and in the process of making the deck jig
Can any one help me
Thanks
Matt (apprentice boatbuilder)

Hi Matt

I wouldn't worry about it and continue with what your doing the difference is not going very much. Not to take anything away from Roberts 3mm construction, 4mm will be stiffer and stronger, and I'm not too sure, but I've read somewhere 3mm is getting hard to get, maybe someone else can clarify that.

Regards

Hi Matt,

My mossie was built in 92 and used 2mm ply. The boat today was still underweight but very soft, you have to watch where you stand on it.

My old boat 1635 used 3mm ply and Cameron took some off the decks and Im pretty sure that was very close to minimum weight.

William

Hi Will

Are you sure it was 2mm, that doesn't sound right.

Regards

Hi Guys,

While on the subject of "softness" , I've got a crunchy deck again, next foam frame up from the one I had replaced when I had the paint job done. It's not too bad so I've decided to sail the season with it and deal with it next winter. A few people in here have suggested that a Mozzie deck is not too difficult to replace. Would that be the case if you had the wood working skills of a "cerebraly challenged gnat"? <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

I know I need to learn these things but I really wouldn't know where to start to get some knowledge? <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

Cheers

Yeah Wills boat Jive was previously called Smik was built of 2mm ply and comes in under weight at around 50kg.His main deck was 3mm I believe.

My new 3mm deck is reinforced with 120 gram glass on the inside. The downside is it does tend to flex and I have small hairline cracks in my paint job. Possibly by using 4mm with a layer of glass or 3mm with 2 layers of glass it would be alot stiffer but stll a few kgs lighter.

I'd also like to point out removing the old deck is not easy and I had a few areas damaged due to this. All repairable and not structural but If you get unlucky it could create a can of worms.

Hi Matt,
My boat is made of 2mm ply which makes it extremely soft and to more get a bit more technical the builder actually travelled to Vic to get the 4 lightest sheets possible. The builder was really picky with this boat to get it down to weight.

William

hey guys
thanks for the information, im a competive sailor and i know how weight is important, i have been on the measurement all the way through this project, and im just worried/ scared, that it wont come into measurement and over weight as its my first competive boat im building, i have been told to stick with the plans at 4mm ply as stated above that any lighter the hulls are soft and wont last as long as the ones built in 4mm. i got the ply from "plywood constructions" in airport west vic, as my friend in the class is building the blade, we tried to bend it and the ply broke/ split from the keel to the stringers and im hoping it dosent happen to mine. so i hope my boat comes on weight or just under cos i want to be number 1, so look out guys, lol
thanks
Matt

Hi Matt

I hope you took a good long look at the Mosquito Building Rules and Regulations and the current boats before you started.

One thing to make sure of is that you have the centreboard case at the maximum measurement from the bow (ie. as far back as it's allowed).

my boat has not been oficially weighed yet but each hull used to weigh 20kg. i am currently adding another layer of 3mm ply to the main deck, as i belive the deck was to soft and i put a small crack in the deck ply when coming in off the wire at the cat clasic.

so i would not recomend using just 3mm ply with glass underneth it anymore. i think on my next boat i will just double deck it from the start.

on the matter of 3mm and 4mm ply i used 3mm ply as i could not get 4mm ply with equal core thickness as required in the plans , having a thicker core makes the ply harder to bend, and might be the reason matt stones friend had his blade split when folding up. the 3mm still has a thicker core but is easier to bend than the 4mm.

if using 4mm make sure you steam up your hull before bending and pul it up slowly with rope to get your shape befor putting in the jig, just my sugestion anyway.

Agreed, I went ahead and used 4mm with a thicker core, but all went well patience and plenty of steam. I did put a small crack in the ply when folding, but was easily fixed and tried again later, with more patience and no worries. I used 4mm on the main and rear decks and 3mm on the forward decks, all with a layer of light glass.

Regards