diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5ec38a..b0037ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/),
 and [PEP 440](https://www.python.org/dev/peps/pep-0440/).
 
+## [0.7.1] - 2023-11-21
+
+### Fixed
+
+- maximum resistance in API_clay where Pmax was wrongly calculated based on depth instead of diameter, credits to Zhenghui Qiu for spotting this.
+
+
 ## [0.7.0] - 2023-11-12
 
 ### Added
diff --git a/src/openpile/globals.py b/src/openpile/globals.py
index 48ec9b2..de8af4a 100644
--- a/src/openpile/globals.py
+++ b/src/openpile/globals.py
@@ -1,2 +1,2 @@
 # version of the package
-VERSION = "0.7.0"
+VERSION = "0.7.1"
diff --git a/src/openpile/utils/py_curves.py b/src/openpile/utils/py_curves.py
index a3c0073..c22748a 100644
--- a/src/openpile/utils/py_curves.py
+++ b/src/openpile/utils/py_curves.py
@@ -349,7 +349,7 @@ def api_clay(
     # Calculate Pmax (regular API)
     ## Pmax for shallow and deep zones (regular API)
     Pmax_shallow = (3 * Su + sig) * D + J * Su * X
-    Pmax_deep = 9 * Su * X
+    Pmax_deep = 9 * Su * D
     Pmax = min(Pmax_deep, Pmax_shallow)
 
     ylist_in = [0.0, 0.1 * y50, 0.21 * y50, 1 * y50, 3 * y50, 8 * y50, 15 * y50, ymax]
diff --git a/test/test_pycurves.py b/test/test_pycurves.py
index fb2f30c..64c74b1 100644
--- a/test/test_pycurves.py
+++ b/test/test_pycurves.py
@@ -49,7 +49,7 @@ def make(
         J: float,
     ):
 
-        return min(9 * Su * X, (3 * Su + sig) * D + J * Su * X)
+        return min(9 * Su * D, (3 * Su + sig) * D + J * Su * X)
 
     return make