diff --git a/Makefile b/Makefile
index a2062e6fc..ddd967458 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CC=gcc
 CFLAGS=-Wall -Wno-pointer-sign -g
 
-OBJS=main.o dive.o profile.o info.o divelist.o parse-xml.o save-xml.o
+OBJS=main.o dive.o profile.o info.o cylinders.o divelist.o parse-xml.o save-xml.o
 
 divelog: $(OBJS)
 	$(CC) $(LDFLAGS) -o divelog $(OBJS) \
@@ -27,5 +27,8 @@ profile.o: profile.c dive.h display.h divelist.h
 info.o: info.c dive.h display.h divelist.h
 	$(CC) $(CFLAGS) `pkg-config --cflags gtk+-2.0 glib-2.0` -c info.c
 
+cylinders.o: cylinders.c dive.h display.h divelist.h
+	$(CC) $(CFLAGS) `pkg-config --cflags gtk+-2.0 glib-2.0` -c cylinders.c
+
 divelist.o: divelist.c dive.h display.h divelist.h
 	$(CC) $(CFLAGS) `pkg-config --cflags gtk+-2.0 glib-2.0` -c divelist.c
diff --git a/cylinders.c b/cylinders.c
new file mode 100644
index 000000000..5df070227
--- /dev/null
+++ b/cylinders.c
@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <time.h>
+
+#include "dive.h"
+#include "display.h"
+#include "divelist.h"
+
+static struct tank_info {
+	const char *name;
+	int size;	/* cuft or mliter depending on psi */
+	int psi;	/* If zero, size is in mliter */
+} tank_info[] = {
+	{ "None", },
+	{ "10.0 l", 10000 },
+	{ "11.1 l", 11100 },
+	{ "AL72", 72, 3000 },
+	{ "AL80", 80, 3000 },
+	{ "LP85", 85, 2640 },
+	{ "LP95", 95, 2640 },
+	{ "HP100", 100, 3442 },
+	{ "HP119", 119, 3442 },
+	{ NULL, }
+};
+
+static void fill_tank_list(GtkListStore *store)
+{
+	GtkTreeIter iter;
+
+	struct tank_info *info = tank_info;
+
+	while (info->name) {
+		int size = info->size;
+		int psi = info->psi;
+		int mbar = 0, ml = size;
+
+		/* Is it in cuft and psi? */
+		if (psi) {
+			double bar = 0.0689475729 * psi;
+			double airvolume = 28316.8466 * size;
+			double atm = bar / 1.01325;
+
+			ml = airvolume / atm + 0.5;
+			mbar = bar*1000 + 0.5;
+		}
+
+		gtk_list_store_append(store, &iter);
+		gtk_list_store_set(store, &iter,
+			0, info->name,
+			1, ml,
+			2, mbar,
+			-1);
+		info++;
+	}
+}
+
+static void cylinder_widget(GtkWidget *box, int nr, GtkListStore *model)
+{
+	GtkWidget *frame, *hbox, *size;
+	GtkCellRenderer *cell;
+	char buffer[80];
+
+	snprintf(buffer, sizeof(buffer), "Cylinder %d", nr);
+	frame = gtk_frame_new(buffer);
+	gtk_box_pack_start(GTK_BOX(box), frame, TRUE, TRUE, 0);
+
+	hbox = gtk_hbox_new(TRUE, 3);
+	gtk_container_add(GTK_CONTAINER(frame), hbox);
+
+	size = gtk_combo_box_new_with_model(GTK_TREE_MODEL(model));
+	cell = gtk_cell_renderer_text_new();
+	gtk_cell_layout_pack_start(GTK_CELL_LAYOUT(size), cell, TRUE);
+	gtk_cell_layout_set_attributes(GTK_CELL_LAYOUT(size), cell, "text", 0, NULL );
+
+	gtk_box_pack_start(GTK_BOX(hbox), size, FALSE, FALSE, 0);
+}
+
+static GtkListStore *create_tank_size_model(void)
+{
+	GtkListStore *model;
+
+	model = gtk_list_store_new(3,
+		G_TYPE_STRING,		/* Tank name */
+		G_TYPE_INT,		/* Tank size in mliter */
+		G_TYPE_INT,		/* Tank working pressure in mbar */
+		-1);
+
+	fill_tank_list(model);
+	return model;
+}
+
+GtkWidget *cylinder_management_widget(void)
+{
+	int i;
+	GtkWidget *vbox;
+	GtkListStore *model;
+
+	vbox = gtk_vbox_new(TRUE, 3);
+
+	model = create_tank_size_model();
+	for (i = 0; i < MAX_CYLINDERS; i++)
+		cylinder_widget(vbox, i, model);
+
+	return vbox;
+}
diff --git a/display.h b/display.h
index e2e217ff0..d499fc7fc 100644
--- a/display.h
+++ b/display.h
@@ -8,6 +8,7 @@
 extern GtkWidget *dive_profile_widget(void);
 extern GtkWidget *dive_info_frame(void);
 extern GtkWidget *extended_dive_info_widget(void);
+extern GtkWidget *cylinder_management_widget(void);
 extern void update_dive_info(struct dive *dive);
 extern void repaint_dive(void);
 
diff --git a/main.c b/main.c
index 7088a6dfa..dc5453892 100644
--- a/main.c
+++ b/main.c
@@ -215,11 +215,9 @@ static void create_radio(GtkWidget *dialog, const char *name, ...)
 
 	box = gtk_hbox_new(TRUE, 10);
 	gtk_container_add(GTK_CONTAINER(GTK_DIALOG(dialog)->vbox), box);
-	gtk_widget_show(box);
 
 	label = gtk_label_new(name);
 	gtk_box_pack_start(GTK_BOX(box), label, TRUE, TRUE, 0);
-	gtk_widget_show(label);
 
 	va_start(args, name);
 	for (;;) {
@@ -239,7 +237,6 @@ static void create_radio(GtkWidget *dialog, const char *name, ...)
 		gtk_box_pack_start(GTK_BOX(box), button, TRUE, TRUE, 0);
 		gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(button), enabled);
 		g_signal_connect(button, "toggled", G_CALLBACK(callback_fn), NULL);
-		gtk_widget_show(button);
 	}
 	va_end(args);
 }
@@ -296,7 +293,7 @@ static void unit_dialog(GtkWidget *w, gpointer data)
 		"Fahrenheit",  set_fahrenheit, (output_units.temperature == FAHRENHEIT),
 		NULL);
 
-	gtk_widget_show(dialog);
+	gtk_widget_show_all(dialog);
 	result = gtk_dialog_run(GTK_DIALOG(dialog));
 	if (result == GTK_RESPONSE_ACCEPT) {
 		output_units = menu_units;
@@ -359,6 +356,7 @@ int main(int argc, char **argv)
 	GtkWidget *notebook;
 	GtkWidget *frame;
 	GtkWidget *dive_info;
+	GtkWidget *cylinder_management;
 	GtkWidget *menubar;
 	GtkWidget *vbox;
 
@@ -417,7 +415,11 @@ int main(int argc, char **argv)
 
 	/* Frame for extended dive info */
 	dive_info = extended_dive_info_widget();
-	gtk_notebook_append_page(GTK_NOTEBOOK(notebook), dive_info, gtk_label_new("Extended Dive Info"));
+	gtk_notebook_append_page(GTK_NOTEBOOK(notebook), dive_info, gtk_label_new("Dive Notes"));
+
+	/* Frame for extended dive info */
+	cylinder_management = cylinder_management_widget();
+	gtk_notebook_append_page(GTK_NOTEBOOK(notebook), cylinder_management, gtk_label_new("Cylinders"));
 
 	gtk_widget_set_app_paintable(win, TRUE);
 	gtk_widget_show_all(win);