The Bigger the faster.

[Steve101]

A friend who has a Bav 32 wants to know if he gets a Bav 40 will it be faster over longer distances. ie. Plymouth to Portugal. Honest this aint my question, all I care about is chilling out (As long as the grape juice doesn't run out before we hit destination)

 

[kidnapped]

Generally the answer is ... the longer the water line, the faster the boat. [assuming similar style of boats]

 

[Twister_Ken]

Providing the crew is strong enough to handle the heavier gear to its max

 

[charles_reed]

No contest.
The longer the waterline the faster the boat.
For modern, reasonably slippery boats the displacement maximum is about 1.4 knots X square root LWL FT.
Some displacement boats, given the right conditions will surf at above this speed, at the risk of terminating the crew due to overstimulation.
There is I believe an old saying "In a blow, a big bad'un is better than a small good 'un".

 

[Jeremy_W]

The really important point is...

.. if the red wine runs out in Northern Portugal, do not succumb to the blandishments of Vino Verde Red - it spectacularly awful!

On the lesser matter: Yacht speed (assuming similar styled yachts) is a function of the square root of the waterline line. A 40-footer will have about a 25% longer water line than a 32-footer so will probably average just over 10% faster. As with lots of these ratios in sailing, do not bother to calculate with any more precision: It really isn't worth the effort because there are too many variables in the Real World.

 

[charles_reed]

Unless you drink Beaujolias Nouveau

In which case your palate will have already been hardened.

Apart from the speed aspect, there are a number of other variables favouring a longer LWL.

Buy the longest LWL your purse will run to.

 

[vyv_cox]

When I owned a GK29 we always used to plan an average 5 knots and never really noticed major inaccuracies. We continued to do the same with the Sadler 34 but realised that our plans were increasingly inaccurate. Last year I calculated our average for the whole season, motoring, waiting for locks and bridges, everything included. Average was almost exactly 6 knots.

 

[RupertW]

I picked up this method of calculating from Coarse Cruising where the author estimated 3 knots for his 22 footer and was rarely wrong over a few miles. Once you've done a few trips in a boat then you can navigate pretty well by just looking over the side and estimating the speed as "average", half a knot above/below, or a knot above/below.

Assuming you do the rest of the traditional nav stuff right, then a log is the least necessary instrument for a known boat.

 

[Twister_Ken]

Beaune of Contention

>Buy the longest LWL your purse will run to<

But realise that LWL don't just cost the sticker price, everything from then on in will cost more - berthing, sheets, fuel, sails, replacement rigging, lifts, storage, etc.

 

[Roberto]

I found a very good average on the long run is about equal square root of lwl in feet, not multiplied by any factor.

I found it approximates very well the miserable speed figure which comes out at the end of the passage when you divide direct route miles of the passage by hours sailed. All seems to average out very well: closehauled sailing, running with the sea, motoring if and when, slowing down for bathing, repairs, etc.

 

[Roberto]

Re: Beaune of Contention

Running costs rise with cubed lwl don t they ?

That means the incremental speed given by delta sqrt(lwl) costs a fortune!

 

[pkb]

You're friend should definitlely upgrade to a 40 if he wants improved boat performance- but whether or not it should be a Bavaria is altogether another matter.

Peter

 

[Steve101]

Eh? Thanks....I think. ;-)