Mast, keel and bulb positions spreadsheet

In blue are the data and in green the calculations.

Formulas and datas:

D6 = volume from Freeship

D7 = LCB from Freeship

CGs = like pictures in previous post

F12 –> F19 = column D * column E

F20 = Sum F12 –> F19

D21 = Sum D12 –> D19

D22 = F20/D21

D25 = D6-D21

E25 = (D6*D7 – D21*D22)/D25

D28 = D25+D21

D29 = (D25*E25+D21*D22)/D28

The problem is: where is the keel and bulb positions.

The keel has need to be according the sail area CG and the bulb CG need to be in accordance with the others CG weights in manner that the total x CG must be in the same LCB position.

As bulb is fixed in keel we have this compromise too.

Stipulated the lead distance between sail CG area and CG immersed area we can try a multitude of mast, keel and bulb positions (the bulb CG has a position interval along the width of the keel ).

Changing the data in column E (distances from stern) for mast and keel the spreadsheet give the bulb CG position

With the spreadsheet we have now a mathematical help.

We can change the mast and keel positions in column E and see if the bulb position is compatible with keel position.

You can strange my mast position but my rig is una rig (cat rig ?)with mast aft.

The cells D28 and D29 are to check if the CG weight positions adopted are in accordance with D6 and D7 data from Freeship.


About Fred Schmidt

Engenheiro Naval interessado em projeto de veleiros radio-controlados. Naval Architect interested in RC sailboats design
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