# Resistance source during propeller design

**URL:** <https://solarboats.discourse.group/t/resistance-source-during-propeller-design/18>\
**Category:** Resistance & Propulsion\
**Created:** [October 18, 2026, 1:32pm UTC](https://solarboats.discourse.group/t/resistance-source-during-propeller-design/18 "2026-10-18T13:32:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Abhimanyu](https://sea2.discourse-cdn.com/flex042/user_avatar/solarboats.discourse.group/abhimanyu/32/14_2.png) [@Abhimanyu](https://solarboats.discourse.group/u/Abhimanyu)\
**Post date:** [October 18, 2026, 1:32pm UTC](https://solarboats.discourse.group/t/resistance-source-during-propeller-design/18/1 "2026-10-18T13:32:16Z")

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When we select “I have a resistance curve” on the left pane, on the right side under Propeller/Propeller Design, the Resistance source still gives drop down for “Holtrop,…” as if we are estimating. Remove this.

 ![Resistance source - with curve too](https://us1.discourse-cdn.com/flex042/uploads/solarboats/original/1X/53f87028e3db414ee1c4c65914297cb9b97ec06a.png)

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<div class="post-metadata">

**Author:** ![Sandith](https://sea2.discourse-cdn.com/flex042/user_avatar/solarboats.discourse.group/sandith/32/11_2.png) [@Sandith](https://solarboats.discourse.group/u/Sandith)\
**Post date:** [October 18, 2026, 1:36pm UTC](https://solarboats.discourse.group/t/resistance-source-during-propeller-design/18/2 "2026-10-18T13:36:41Z")

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The drop down is now removed when the “I have resistance curve is selected”. Until the two rows of data is entered, an information is displayed “ **No measured curve yet.** Enter two points or more in the table on the left. Until then the propeller is designed against the **Holtrop** estimate, so the design below is provisional.”

 ![Resistance source - no drop down](https://us1.discourse-cdn.com/flex042/uploads/solarboats/original/1X/fd74b2b59a26ca200f847e7af146f94e682f2d47.png)