Hi Eddy,

no i started building of the mastermodel, made a mould and laminated my hull only by my own opinion i thought it will be allright and so far it seems to be OK, the weight of the hull only is 3.5 KG around 7 pound.

Regards Hans

Hi PD's ......calculating the displacement  [ not weight] of the model prior to manufacture is not difficult 

1) go to the green grocer....select three empty polysterene brocilli boxs & tak'em home for FREE
2) cut into 300 mm long x 50 mm wall thickness x the beam [width] of planned vessel
3) laminate with contact glue sufficient layers to a keel level to deck level height
4) roughly sand the bilge keel radius to both sides
5) scribe a TEXTA line of the proposed water line
5) take to the test tank [bath] & place the kitchen or bathroom scales & exert a downward force to equal the dispalcement @ water line...record this value [in kg's]
= result 1

Repeat steps 1), 2) & 3)

6) roughly sand the next 300 mm long section to represent the bow section

Repeat steps 5) & 6)
= result 2

Repeat steps 5) & 6)
7) Same applys for an AFT sanded section...
= result 3

So if the 1:48 model of Glen Sannox was 1700 mm long.....the confirmed displacement would =

Total displacement = result 3 + result 2 + [the middle bits ....or 3.66 times the weight of result 1]

This is totally true & so simply effective as we consider only displacement... not weight of materials

OK PD's ...I am asked a question OFF Line.....how do you calculate the bow & stern sections?

1) use the same rough sanding method to shape the sections & by eye....to best suit your plan
2) divide each 300 mm long polystyrene section by 10 & superimpose these with TEXTA as frames over the section
3) using a piece of string, gauge the total length from water line to water line over each frame line & record the dimensions

From this a table of dimensions can be established...these cordial lengths can also be used in later planing

After all....the Vikings & Romans used similar principals many years ago  & before