diff --git a/rowers/models.py b/rowers/models.py
index 8e024c1d..c4495b5b 100644
--- a/rowers/models.py
+++ b/rowers/models.py
@@ -875,9 +875,11 @@ class WorkoutForm(ModelForm):
             
 # Used for the rowing physics calculations
 class AdvancedWorkoutForm(ModelForm):
+    quick_calc = forms.BooleanField(initial=True,required=False)
+        
     class Meta:
 	model = Workout
-	fields = ['boattype','weightvalue']
+	fields = ['boattype','weightvalue','quick_calc']
 
 class RowerExportForm(ModelForm):
     class Meta:
diff --git a/rowers/tasks.py b/rowers/tasks.py
index cdd1f807..9f7c971d 100644
--- a/rowers/tasks.py
+++ b/rowers/tasks.py
@@ -356,10 +356,7 @@ def handle_sendemailcsv(first_name, last_name, email, csvfile,**kwargs):
 def handle_otwsetpower(self,f1, boattype, weightvalue,
                        first_name, last_name, email, workoutid,
                        **kwargs):
-#                       ps=[
-#                           1, 1, 1, 1],
-#                       ratio=1.0,
-#                       debug=False):
+
     job = self.request
     job_id = job.id
     
@@ -378,7 +375,12 @@ def handle_otwsetpower(self,f1, boattype, weightvalue,
         debug = kwargs['debug']
     else:
         debug = False
-        
+
+    if 'quick_calc' in kwargs:
+        usetable = kwargs['quick_calc']
+    else:
+        usetable = False
+
     kwargs['jobid'] = job_id
 
 
@@ -416,8 +418,10 @@ def handle_otwsetpower(self,f1, boattype, weightvalue,
         pass
 
     progressurl = SITE_URL
+    siteurl = SITE_URL
     if debug:
         progressurl = SITE_URL_DEV
+        siteurl = SITE_URL_DEV
     secret = PROGRESS_CACHE_SECRET
 
     progressurl += "/rowers/record-progress/"
@@ -431,7 +435,7 @@ def handle_otwsetpower(self,f1, boattype, weightvalue,
                                 powermeasured=powermeasured,
                                 progressurl=progressurl,
                                 secret=secret,
-                                usetable=True,storetable=physics_cache,
+                                usetable=usetable,storetable=physics_cache,
     )
 
     # save data
@@ -470,7 +474,8 @@ def handle_otwsetpower(self,f1, boattype, weightvalue,
     message += "Thank you for using rowsandall.com.\n\n"
     message += "Rowsandall OTW calculations have not been fully implemented yet.\n"
     message += "We are now running an experimental version for debugging purposes. \n"
-    message += "Your wind/stream corrected plot is available here: http://rowsandall.com/rowers/workout/"
+    message += "Your wind/stream corrected plot is available here: "
+    message += siteurl+"/rowers/workout/"
     message += str(workoutid)
     message += "/interactiveotwplot\n\n"
     message += "Please report any bugs/inconsistencies/unexpected results at rowsandall.slack.com or by reply to this email.\n\n"
diff --git a/rowers/templates/otwsetpower.html b/rowers/templates/otwsetpower.html
index 51218c6a..7a997bed 100644
--- a/rowers/templates/otwsetpower.html
+++ b/rowers/templates/otwsetpower.html
@@ -35,6 +35,10 @@
 	We use FISA minimum boat weight and standard rigging for our calculations. 
 	</p>
 
+        <p>The Quick calculation option potentially speeds up the calculation,
+          at the cost of a slight reduction in accuracy. It is recommended
+          to keep this option selected.</p>
+
     <form enctype="multipart/form-data" action="{{ formloc }}" method="post">
     {% if form.errors %}
         <p style="color: red;">
diff --git a/rowers/views.py b/rowers/views.py
index dec96cc4..a19d7eeb 100644
--- a/rowers/views.py
+++ b/rowers/views.py
@@ -6728,12 +6728,14 @@ def workout_otwsetpower_view(request,id=0,message="",successmessage=""):
 	form = AdvancedWorkoutForm(request.POST)
 
 	if form.is_valid():
+            quick_calc = form.cleaned_data['quick_calc']
 	    boattype = form.cleaned_data['boattype']
 	    weightvalue = form.cleaned_data['weightvalue']
 	    row.boattype = boattype
 	    row.weightvalue = weightvalue
 	    row.save()
 
+
 	    # load row data & create power/wind/bearing columns if not set
 	    f1 = row.csvfilename
 	    rowdata = rdata(f1)
@@ -6770,7 +6772,9 @@ def workout_otwsetpower_view(request,id=0,message="",successmessage=""):
 			  weightvalue,
 			  first_name,last_name,emailaddress,id,
                           ps=[r.p0,r.p1,r.p2,r.p3],
-                          ratio=r.cpratio)
+                          ratio=r.cpratio,
+                          quick_calc = quick_calc,
+            )
 
 	    try:
                 request.session['async_tasks'] += [(job.id,'otwsetpower')]