How to send out auto filled forms to race participants

I am the coordinator for an annual sailing regatta where we have about 90 entries each year.

How can I auto fill part of a form, based on previous year's entries and email it to the potential entrants for this year?

(name, address, phone number, email address, boat name, sail number, etc)

I am hoping not to have to do this 150 times, as we have a slightly different list of entrants each year.

JotForm does not have the ability to do this, but I think you may implement a workaround using Google Sheets, the first thing that you would need to do is integrate your form with Google Sheets so you have all the submissions data synced in one sheet: https://www.jotform.com/help/228-How-to-Integrate-Form-with-Google-Spreadsheet 

You may remove the integration once it has been created, this will not remove the spreadsheet. 

Then you will need to create the hyperlink on the sheet and pick the the values from the cells you need, example, name, email address, phone number or address. 

To generate the base form URL with the pre-populated data you may follow this guide: https://www.jotform.com/help/71-Prepopulating-Fields-to-Your-JotForm-via-URL-Parameters 

Now, you will need to first concatenate the URL with the the parameters in order to include the values in the cell, this link will provide  you more information about it: https://support.google.com/docs/answer/3094123?hl=en 

Once you have the string concatenated with the form URL and the parameters from the URL you may copy each link accordingly and share it with the correct user.

Also, you will be doing this for the first row only, then you may use the autofill feature of Google Sheets and get the links for the rest of the rows: https://support.google.com/docs/answer/75509?co=GENIE.Platform%3DDesktop&hl=en 

I hope this helps.