Victoria Shadow Association Members' Forum

David_Pereira

Resigned

Registered: 2016-07-12

Posts: 27

V800 Centre of Gravity

I am about to drill holes in my boat hull for permanent fixings for a pair of "Yachtlegs". I am trying to work out how far along the shearline I should position the fixings so that [in theory] the legs are only acting as lateral support to prevent toppling. I wonder if anyone has knowledge of the location dimensions for the theoretical Centre of Gravity of Victoria 800's as at first launch stage. My definition of the CoG is " the balance point of the mass of the boat and its contents".

My practical solution will be to ask the boatyard to lower the boat down onto a flat hard surface and just take all weight off the hoist slings to see what attitude the boat adopts and then decide on the leg positions. However it would be nice to have a theoretical crosscheck.

Any help and comments would be much appreciated. I only want to drill once!
david

Jonathan_Hopper

Member

Registered: 2004-03-23

Posts: 155

Re: V800 Centre of Gravity

David -

When drying out the F26 she settles down at the nose.   Before Francesca changed from a Yanmar to a Beta she used to do it more, and the weights of each aren't that far apart, so I suspect that stowage weight/people could also have an affect.   Thus I think that the legs will only take a little weight from the pitch of her drying out, but this will make her more stable.  Hopefully this photo will give you an idea where she settles - apologies for not being able to find anything better.

It looks as though putting the legs reasonably well forward will give you less pitch when you dry out - perhaps towards the front of the coachroof - maybe just aft of the shrouds?   Too far back and she will pitch - this will leave the legs at an angle which I guess you want to avoid.

Given you need to install backing plates and not knowing the interior of your V800, this may dictate their exact position.

Shikara has Yacht Legs fitted, and you will see the brackets on one of the photographs here: http://www.victoriashadow.co.uk/forum/v … php?id=168

David_Pereira

Resigned

Registered: 2016-07-12

Posts: 27

Re: V800 Centre of Gravity

Johnathan
Many thanks for your reply.  It looks as if just behind the shrouds is a good starting point. The reason for my CoG query is to try to establish the 'theoretical fulcrum' so that I can make a stab at a maximum theoretical loading ahead of the legs.  for example 2 people on the foredeck, anchor and chain, kit in the forecabin and full watertank. Then from this to derive a leg position that gives a small but positive load on the legs.  I pumped out the water tank yesterday and noticed that the bows lifted about 2" so final decision will be an informed guess!
david