I’m looking for an app that I can use to set the stroke rate I want to row to.

Can you help please, Thanks 

I think that what you are looking for is a metronome app – this will give an audible beep set to the number of counts per minute (stroke rate).

Here is the Rowing Metronome app (IoS only).
You don’t say whether you are Android or IoS user – but I suggest you search in the music apps.

• Reviews 5 of the best
• Here’s one which you can use on a computer (while using a rowing machine?)
• And this one has Android and Apple app uses and also an IoS version

Now, I will add that if you are in a coxed boat, the Coxmate SX amplifier has a metronome function.  They also have an alarm so if you are a coach you can send your crew off towards the regatta start and set it to go off 15 minutes before they need to be up there….. And if you need a smart phone mount to take your phone safely in the boat – we sell them too.

A brief search also finds this Quora question where they have set up Web Metronome to help set a 2:1 ratio

Animation of rowing to a metronome

Do send me your feedback if this answers your question.