Enumerable.Batch

Sub Main

    Dim record As String = New String("0", ((240 * 3) + 7))

    Dim ChunkLength As Integer = 240

    Dim chunks As List(Of String) = Enumerable.Range(0, Math.Ceiling(record.Length / ChunkLength)).Select(Function(i) record.Substring(i * ChunkLength, Math.Min(ChunkLength, record.Length - (i * ChunkLength)))).ToList


    chunks.Dump()

End Sub