JettyMap Tags

When you create a Course or Directions in JettyMap it is nice to be able to format it – make some text bold, add a title, start a new line. There are special JettyMap tags you can use for this. They look like:

Bold [bold-start] and [bold-end]
Paragraph [p-start] and [p-end]
Title [title-start] and [title-end]
Subtitle [subtitle-start] and [subtitle-end]
List [list-start]and [list-end]
List Item [listitem-start] and [listitem-end]
Link [link-start], [link-text] and [link-end]
New line [new-line]

So to get a course notice that looks like this:

Start: Green North – 1p – GMp
Course: 4s 8s 2s 5s 7s 3p 9p
Laps: until shortened
Finish: Committee Boat Finish from 3

Club website is here

Your notice area looks like this:

[bold-start]Start: [bold-end]Green North – 1p – GMp
[new-line][bold-start]Course: [bold-end]4s 8s 2s 5s 7s 3p 9p
[new-line][bold-start]Laps: [bold-end]until shortened[bold-end]
[new-line][bold-start]Finish: [bold-end]Committee Boat Finish from 3
[new-line][new-line]Club website is [link-start][link-text]here[link-end]

Why use Average Lap Times for club races?

The latest version of Boat Timer can now produce results for Average Lap Time racing. But why would your club want to use this method of race timing?

Many clubs run handicap races or a mix of class racing and handicap racing. Handicap racing allows almost any boat to join in a race. You often see fast boats like RS100s, Merlin Rockets and Aero9s on the same start as slower boats like Mirrors, Laser 4.7s, Cadets and RS Teras. These races are fairly informal – it is difficult to get a handicap system that is perfectly fair to every boat in every type of weather – but they are great fun and because everyone is on the water at the same time they are great for getting to know your fellow club members.

But one complaint you might hear from the sailors – especially if you are on the race team – is about the length of the race.

If you sail a fast boat, you may have a very short race. If the race team are trying to run a race for about an hour, then they have to finish the fast boats by 45 minutes in order to finish all the slower boats by 1 hour 15 minutes at the latest. A bit frustrating if it is a nice day.

So that is why Average Lap Time races are becoming popular at some clubs. The race team lets everyone race for about an hour and then sounds a finish warning signal, after which each boat finishes as soon as it reaches the finish line on the current lap.

Fast boats might complete 4 or 5 laps in the hour-long race and slower ones maybe 2 or 3, but every boat gets about an hour of racing. And every sailor is happy. Worth trying at your club?

Boat Timer – Switching the list of classes or countries

In Boat Timer you can edit the default classes, countries and handicap values easily. However, it can take some time to change a whole list of them. But here is a quick way to change things to suit your club’s location and the boats you sail.

Using the backup and restore options, you can import a file of countries or classes. Usually the restore option overwrites everything in the app (it is a restore option, after all) but the class or country files on the website only change part of the information in the app, so your races are not changed. And using these files is a quick way to completely change the classes or countries.

If you want to learn how to use these files in the app, this page on customising Boat Timer will explain how. the page also has the download links for each file.


Your club may sail different classes to the app defaults and may use a different handicap/rating system for race results. The first two files are for IRC (a rating system for yachts) and Weymouth (a handicap system used in Australia for dinghy racing).


In a rating system, each boat has a rating number calculated according to a formula based on the boat’s length, sail area etc. So the Boat Timer file included different classes for each rating number. For example, if your yacht has an IRC rating of 978 the Boat Timer class is IRC2 0978 (the 2 refers to a group of yachts of a certain speed, 1 being the fastest and 6 the slowest). You may have to select a different class for each yacht, but once done the app will calculate corrected finish times for the race.


The Weymouth file gives you a list of classes (dinghies and cats) more appropriate for Australian clubs and applies the Weymouth handicap numbers to each class. There are other handicap systems in use in Australia so watch out for new files to support them in the future. And do get in touch if your club uses a system that should be supported by the app.


Country files are available for many parts of the world and more files will be available in the future. Countries in the Middle East and Asia are only available in the “world” file at the moment, but that will be remedied soon. These country files let you change the list in the app to better reflect the location of your club.

Using “Move Up” in Boat Timer

On the Boat menu (the one that appears when you click on a square on the race grid) there are several options. Most are obvious: Retired, Disqualified etc but there is also Move Up. So what is it and why would you use it?

If your club’s fastest sailor gets to the first mark and capsizes, they might get to the end of the first lap in the bottom half of the fleet. As a race officer you know that he/she is going to move up through the fleet as the race progresses. At the finish, your fast sailor might be near the front of the fleet on the water but halfway down the race grid in Boat Timer. That is when Move Up is useful.

Each time you press Move Up it improves that boat’s lap time by 30 seconds. So if you use it enough times the boat will move higher up the Boat Timer race grid, making it easier to find them at the finish or at the end of the next lap. The boat has to complete at least one lap for Move Up to work – on the first lap there is no lap time to improve and the boats are just ordered by sail number and class.

Just to be clear, the Move Up action doesn’t actually change the lap time or finish time of any boat. It is only used when Boat Timer is updating the order of the boats on the race grid. But it does allow you to push boats further up the race grid to match what is happening on the water.

Boat Timer and the Weymouth rating system

The Boat Timer app works out corrected times for any rating system. But not all rating systems use the same method to do the calculation, so a club in New Zealand using the Weymouth system got in touch to ask if it could be used with Boat Timer.

The Weymouth rating numbers are ratios, so a Laser has a Weymouth number of 0.91 and a slower boat such as a Laser 4.7 has a Weymouth number of 0.87. This makes calculating a corrected time simple as you can multiply the Weymouth number by the time the boat took to complete the race to get a corrected time.

As Boat Timer uses a different method based on UK ratings systems to calculate the corrected time, the Weymouth number has to be converted. Fortunately this is not hard; dividing 1000 by the Weymouth number gives you a rating number that works in the app.

But why 1000?

UK Rating Numbers

In the UK, most races use the Portsmouth Yardstick (PY) though there are others in use; the Great Lakes system for example. These two use a baseline of 1000, by which I mean boats are given a number that is above 1000 for slower boats and below 1000 for faster ones and that number is used to calculate a change to the boat’s finish time.

The formula for these baseline 1000 systems is:

e / r * 1000 = c


e is elapsed time in seconds (the time a boat took to complete the race)
r is the rating number
c is the corrected time in seconds (the time you use for scoring the race)

American Rating Numbers

In the USA, the US Sailing D-PN system was based on the UK PY system but modified for their own racing conditions and classes. It is a baseline 100 system so rating numbers typically range from 80 for a fast boat to 120 for a slow one. Interestingly the USA system has the option of using different ratings for different wind strengths. It is fair to say some types of boat are better in lighter winds and some better in stronger, so the D-PN table has a general D-PN number similar to PY but also has D-PN1, D-PN2 D-PN3 and D-PN4 for the different wind strengths. So you can choose whether to use the all-weather number or go for a fairer number for the race conditions.

As Boat Timer assumes a baseline 1000 system and D-PN is a baseline 100 system, using a D-PN number in Boat Timer requires converting it by multiplying the D-PN rating by 10.

Creating Rating Systems In Boat Timer

At present, Boat Timer has the PY and Great Lakes rating systems in the app, though more will be added in the future. But it is possible to add your own system.

In the Options – Classes menu you can open a class document (for example, the Laser class) like this:

To add a new system, fill in the name of the system (eg. Weymouth or D-PN) in the New Rating Type box, add the Laser number in the Rating Value box and press the Update Class button.

When you open other classes, you will see the new system in the options for Rating Type. Initially, any class you have not edited will have a rating value of 1000 so it is necessary to add values for the classes in your races. Don’t forget to convert the rating number to a value that works in Boat Timer.

And finally in your race, select the new Rating System for each start and your rating system will be used to produce results on corrected time:

Defining Dinghy Classes

Now that we are starting to use computers routinely to manage race information it is a good time to improve things and define a standard that different software applications can share

A Proposed Standard: Boat Timer Standard Class Definitions

Sailors usually know the difference between a Laser Radial and a standard Laser and that the two boats go at different speeds. Trouble is, computers are not as smart as people. Now that we are starting to use computers to routinely manage race information it is a good time to improve things and define a standard that different software applications can share.

This means that there is always an easy way to be sure of the corrected time calculation for that class and what boat specification was used in a race

In writing the Boat Timer app I had to define an “internal” standard for an ID so that the app could accept race entries using a common name, such as “Laser Radial” and refer to that class internally by the ID so that even if the name changed (it can happen – the Laser 2000 is now an RS 2000 for example) it would carry on working. This means that there is always an easy way to be sure of the corrected time calculation for that class and what boat specification was used in a race.

I decided I would assign an alphanumeric ID code (so no spaces or punctuation) that was limited to eight characters. A Laser Radial became “LsRadial” whereas a standard Laser was still just “Laser” and a Laser 4.7 was “Laser47”. I tried to pick an ID that was still easy to identify, so the Laser Pico is just “Pico” and the aforementioned Laser 2000 is “2000”.

To link the ID back to the names we are familiar with, the standard includes a class, subclass, name and shortname. For the Laser Radial the class is “Laser” and the Subclass and shortname are “Radial” and the name is “Laser Radial”. The shortname is better than name when displaying a table of race results so the column title for the class is not too wide. You may not use all five different parts of the standard – the name and shortname are the most useful when displaying information – but they allow the standard to be flexible and used in a number of different ways.

So the Boat Timer standard class definition for the Laser Radial is:

ID: LsRadial
Class: Laser
Subclass: Radial
Name: Laser Radial
Shortname: Radial

the Laser is:

ID: Laser
Class: Laser
Subclass: <– intentionally blank!
Name: Laser
Shortname: Laser

and for a Devoti D-Zero (hopefully a good example) it is:

ID: DZero
Class: Devoti D-Zero
Subclass: <– intentionally blank!
Name: Devoti D-Zero
Shortname: D-Zero

You might wonder the D-Zero and D-One are not treated like the Laser Radial and have a class of “Devoti” and subclass of “D-Zero” or “D-One”. There is a reason for this: the Devoti D-Zero is not the same boat as the Devoti D-One, so one is not a variation of the other. But the Laser 4.7, Radial and standard Laser are the same boat with three different rigs, just like the RS Aero 5, 7 and 9.

Notice that the “-” has been dropped from the ID of the D-Zero but not from the shortname. The shortname is limited to eight characters like the ID, but it can include characters like “-” and “.” that the class normally use to describe the boat. The same is true for the 2.4mR which has an ID of 24mR but a shortname of 2.4mR.

Just an aside – there are two different sizes of rig for the D-Zero, a 6.9 and an 8.1. But the RYA PY tables only list a single entry for the D-Zero. I must get to the bottom of that one. I guess it just shows that having a standard for classes is useful, we will need a DZero81 in the list in the future (if the RYA are referring to the 6.9 rig?).

To make sure the Boat Timer standard list of classes is available to everyone just by using a browser, the Boat Timer server now has a way to easily get the information in two different formats

To make sure the Boat Timer standard list of classes is available to everyone just by using a browser, the Boat Timer server now has a way to easily get the information in two different formats. To get it in JSON format, which is a format commonly used for data exchange between web servers the address is:

For the CSV format used by many desktop programs like HAL Results and Sailwave the address is:

If you see any mistakes or omissions, please email me at ian.cherrill here at so I can correct the list. There are a number of rare or older classes not on the list, so if you use one of those for racing I will be happy to add it.

Boat Timer – where do I start?

What does it do?

Boat Timer exists to make timing a lap or finish easier in a sailing race. Writing down times on paper as several boats finish near each other is difficult, but in the app you just press a “Finish” button.

How do I run it?

Boat Timer runs in your browser, so you just go to

There are options in the app to install it so you have an icon on your desktop, but you do not have to use these for Boat Timer to work.

There is no internet or phone signal – can I still use it?

Yes. You need the internet to open Boat Timer the first time, but after that it can be used without the internet.

Can it run on my phone?

Not really. It is possible on some phones, but the screens just aren’t big enough to record the boats.

What about a tablet?

Yes. The touchscreen makes it a quick way to record finishes.

A word of warning – Apple devices such as the iPad can be used, but they are not as good a choice as an Android tablet for some technical reasons. In particular, the export and backup options do not work on an iPad. However the timing or a race and viewing results do work correctly.

If you have an Android tablet you can use either the Chrome browser or the Android app for Boat Timer.

What sort of laptop can I use?

Just about all of them. Ideally you should install the Chrome web browser (even on a Macbook). But a variety of systems should work, including Windows 7 & 10, Apple Macbooks, Chromebooks and various types of Linux. An up-to-date version of the Chrome browser is the best way to get a good Boat Timer set-up.

I have more than one start in my club races. Will Boat Timer cope?

Yes. In the “Race” page you can add as many starts as you like. You get results for each start.

Does it do results of handicap races?

Yes. You set each start in a race to use a rating system like Portsmouth Yardstick. This will be used automatically to produce a results table at the end of the race.

Does it upload results to the internet?

Your club can sign up to Boat Timer “Cloud Services” in order to sync information with the internet. This gives your sailors online entries and results on the web as soon as the race is over. The Cloud Results Service calculates race results on handicap (for races using a rating system) and gives you a series or event table, based on your discard and scoring choices.

Clubs can get online race entries and instant race results using Cloud Services for a small monthly fee.

Is Boat Timer free?

Yes. You can use it to time races free of charge – no registration required. The app produces results at the end of the race (including corrected times if you use a rating system) which can be printed off or exported to a CSV file.

How can I print the results table?

There is an “export” option in the results for the HTML format (a web page). If you export the results to that format you can open the file in your browser and print the page. As it is an HTML file on your computer you do not need the internet to see it.

Can I export the results to Sailwave?

Yes. There is an export to CSV format option in the results. You can use that CSV file to transfer results to another scoring system like Sailwave.

The first blog post: what’s the problem?

if you love the sport of sailing you already know the feeling of freedom that helming your own dinghy around a lake or harbour gives you. There’s no path you must follow and no engine to start, you decide where to go and the wind and water is the way you move along. If you were lucky enough to sail as a child you won’t have forgotten the feeling that you finally get to decide where to go and what to do.

I know some people think of sailing as an expensive, even elitist, sport but I don’t believe that. I grew up sailing Mirror dinghies which were designed by a DIY television celebrity of the day, Barry Bucknall, and a top boat designer, Jack Holt. The 60s saw the start of a craze for dinghy sailing and racing in the UK that gave many people their first taste of sailing and led to an extraordinary series of performances at the Olympics from UK sailors such as Rodney Pattison, the super-fit Royal Navy sailor of the late 60s and early 70s to the modern-day medallists Iain Percy & Andrew “Bart” Simpson, Ian Walker, Ben Ainslie, Shirley Robertson, Sarah Ayton, Sarah Webb, Pippa Wilson, Hannah Mills, Saskia Clark and Paul Goodison, to name a few.

Lately the cost of sailing seems to have risen and a lack of spare time plus competing activities seems to have led to a drop in the number of people wanting to sail dinghies. That has to change: sailing is such a unique experience and gets adults and children away from the pressures of modern life in a way that very few other sports can.

So what is the point of this website?

Rotor-Rig is a name I gave to a number of projects to try to help dinghy sailing at the “grass roots” level – a really bad term for a water sport I know, but I hear it a lot. Sailing’s grass roots are the local clubs that give everyone a first opportunity to learn dinghy sailing and racing in a safe environment. The first project is “Boat Timer” – an app to make timing races and recording the results quicker and easier, hopefully meaning that sailors see their results quicker and fewer volunteers are needed to run a race. You can get the app for your laptop at as well as an Android version in the Google Play Store. There’s also an app called Rooster Signals that might help with sound signals for training races.

There’s more to come though. In Covid lockdown I started to work on Jetty Map, an app not only to map the location of sailing clubs (that’s already been done by the RYA, among others) but also to map the club buildings, start and finishes lines and racing marks and – if they have standard courses – the courses they use. Almost every club website has a map of their location, but adding information relevant to club racing makes a club easier to understand for those new to it. I haven’t finished Jetty Map yet, but you can see an example of the mapping of racing marks in this map of Chichester Harbour clubs.

I write software for a living, so these projects are familiar territory for me. But there are plenty of other problems to solve. I am not the only one concerned about the number of unused boats in most sailing club boat parks. They are cheap to buy secondhand, but avoided for racing by most sailors for a number of reasons. Yet we have a surprisingly large number of new classes of boats aimed at racing sailors for – what seem to me at least – large sums of money. I bought my old RS200 for £2,000 a number of years ago but if I want a new one it is going to cost me around £12,000. I think we have to remember that this sort of money for a sport you do one day a week is beyond a lot of people. I don’t have all the answers to this, but I am kicking some ideas around for a new class of dinghy called the Frensi. More on that in another blog post.