New Sails vs Old Sails

Sails – Out with the old and in with the new.

A guide to the noticeable performance difference between hanging on to old sails and splashing out on some new ones.

The purpose of this guide is to give some informative advice, facts and what to look for when considering new sails.

Sails can cost a lot of money, may not seem like they are worth it as the old ones are still white (ish) and the thought that ‘we aren’t racing’ may well put off the purchase of some new canvas until another year or two.

Well, this is all true.

I’m not a ‘sailsman’ and nor do I have any commission based arrangement with sailmakers (perhaps I should), however I wanted to pass on some thoughts and information to you regarding the difference between old sails and new sails and the difference they make to the overall performance – speed and pointing ability of your boat.

A yachts’ primary driving force are her sails, and not the noise machine under the cockpit! After all, you di purchase a sailing boat didn’t you?

On this basis alone, your sails are your best investment for your yacht.

They do require annual maintenance, will cost money to initially purchase, however after this, are rather cost effective.  Unlike the diesel engine onboard, they will not pollute, do not make a noise (unless something is drastically wrong), do not need fossil fuels to operate, and once the skill has been mastered, sailing is really rather rewarding!

Comparing old sails to new.

I was recently sailing a 41’ Arcona yacht with old sails in the English Channel. I regard Arcona yachts to be very responsive to good sail trimming and an absolute pleasure to sail. 

The owner of the yacht asked me if new sails would make much difference to the way the boat sailed and handled.

My response was a simple “Yes, and a huge difference.”

The current sails were completely out of shape, delaminating and had badly stretched. This was all because of poor sail care and a lack of maintenance previously.

Seaway Sails

Old Mainsail


Seaway Sails

Old headsail

To me, this is rather poor and not so enjoyable. Having sailed just over 350,000 miles, it felt like driving a fast car with a flat tyre. The boat was going ok, but didn’t respond much to fine tuning, and there was no real enjoyment in my opinion. The owner, seemed to be fairly satisfied with this spiritless performance!

The following season, however, after some more tuition from me regarding sailing, sail trim, boat handling and general confidence building, the decision was made – NEW SAILS!! Fantastic!

New sails onboard, but not hoisted on our day out, I wanted to illustrate to the proud owner of the new bright white sails onboard, the difference between the old and the new.

Some figures;

Sailing upwind in around 8 knots of true wind, with full sail we were cruising along at around 6.5kts, being about 45 degrees off the wind. This seemed to be about our optimum speed / heading ratio. There was a slight chop. Tacking over, there was a marginal difference, around 0.2 of a knot of speed (through the water). I’ve yet to find a boat which sails the same on both tacks! It isn’t down to Coriolis effect, as it is always the opposite tack to which one would expect!

The best way to measure performance in sailing terms is how efficiently and quickly we can sail to windward. This is called Velocity Made Good – or VMG to racers and the instruments which cannot fit all of that text on the same screen!

One can have VMG to a waypoint also, presuming a waypoint is set up into the navigation system.

Calculating VMG without instruments.

We want to calculate our VMG from our boat speed and angle off the wind. This is a simple mathematical sequence. Calculator makes this easier, however not impossible with some paper and a pencil!

Being involved in highly competitive racing, I have become very good at Pythagoras theorem with Sine / Cosine / Tangents etc. This is simply a must when determining the best course / speed / distance to the finish line! The equations of going faster but further compared to going slower and more direct… There is an optimum, trust me!

Calculating VMG:

This is done by simply multiplying the boat speed by the Cosine of the angle off the wind. Easy (ish)!

Some results:

Old sails; 6.5kts multiplied by 0.7071  (Cosine of 45).

VMG is therefore 4.59kts.

We hoisted and rigged the new sails after lunch…..then a cup of tea and chocolate bar later to recover!

New sails – sunglasses needed as they were very white!

Our speed and trimming ability had increased measurably! The equivalent of our sports car having a flat tyre, now had four brand new tyres – much better – a big noticeable difference.

Some results for you – we were able to point much higher with these sails without drastically loosing speed. Pointing at around 35 degrees off the wind gave speeds of around 6.9 knots. We touched 7.0 for a split second – aided by a wave from a passing motor boat!

Our results may not initially sound huge – 10 degrees and 0.4 of a knot quicker. However, when this is converted to VMG, there is a noticeable difference.


6.9kts x 0.819 (Cosine of 35)

VMG is therefore 5.65kts

As a result of this change, our performance was just under 20% better to windward. This is on a constant, smooth sea with slight chop.

The new shape of the sails, and added performance will, in practise, give us slightly more than this figure, when coupled with acceleration from tacking / waves etc. Also there is slightly less heel as the boat is going slightly faster which in turn reduced the amount of friction caused by the weather helm and of course slightly less leeway.

New Mainsail


New headsail

These factors combined, the difference is significant and encourages fine tuning of the sail shape in every way possible.

Notice in the photo’s the smooth shadow in the new sails compared to the uneven and jagged shadow formed by badly shaped sails.

In short, new sails make an enormous difference to the performance of the old sails, and you do not need to be racing to see this!