Resistance – Navalapp

Blue sailing boat on the sea with keel under water

On bulbs (and keels)

<img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' class='avatar avatar-80 photo' height='80' width='80' />

Topics: Advanced | Appendages | Bulbs | Design | Hydrodynamics | Keel | Lift-induced drag | Pablo Sopelana | Resistance | Stability

<img width="640" height="378" src="https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-1024x604.jpeg" class="attachment-large size-large wp-post-image" alt="" sizes="(max-width:768px) 768px, (max-width:1024px) 1024px, 1024px" decoding="async" srcset="https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-1024x604.jpeg 1024w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-600x354.jpeg 600w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-300x177.jpeg 300w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-768x453.jpeg 768w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-1080x637.jpeg 1080w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1-624x368.jpeg 624w, https://cdn.navalapp.com/uploads/2021/06/sailing_boat_from_bow_1.jpeg 1200w" />

Challenges in sailboat design

<img alt='' src='https://navalapp.com/snp-wp-content/uploads/avatars/114/61964d8026f6a-bpthumb.jpg' srcset='https://navalapp.com/snp-wp-content/uploads/avatars/114/61964d8026f6a-bpthumb.jpg 2x' class='avatar avatar-80 photo' height='80' width='80' />

Markku Hentinen

Topics: Advanced | Boat / Yacht | Design | Markku Hentinen | Resistance

<img width="640" height="320" src="https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-1024x512.jpeg" class="attachment-large size-large wp-post-image" alt="Sailing yacht reaching" sizes="(max-width:768px) 768px, (max-width:1024px) 1024px, 1024px" decoding="async" srcset="https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-1024x512.jpeg 1024w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-600x300.jpeg 600w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-300x150.jpeg 300w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-768x384.jpeg 768w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-1536x767.jpeg 1536w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-1080x539.jpeg 1080w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3-624x312.jpeg 624w, https://cdn.navalapp.com/uploads/2020/11/sailing_yacht_reaching_3.jpeg 2048w" />

Sailing yacht reaching

What the hydrodynamic resistance is and why it matters

<img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' class='avatar avatar-80 photo' height='80' width='80' />

Topics: Added resistance | Frictional resistance | Hydrodynamics | Lift-induced drag | Pablo Sopelana | Residuary resistance | Resistance | Wave-making resistance

<img width="640" height="427" src="https://cdn.navalapp.com/uploads/2020/10/test-tank.jpg" class="attachment-large size-large wp-post-image" alt="Hull model being tested in a test tank." sizes="(max-width:768px) 768px, (max-width:1024px) 1024px, 1024px" decoding="async" srcset="https://cdn.navalapp.com/uploads/2020/10/test-tank.jpg 1000w, https://cdn.navalapp.com/uploads/2020/10/test-tank-600x400.jpg 600w, https://cdn.navalapp.com/uploads/2020/10/test-tank-300x200.jpg 300w, https://cdn.navalapp.com/uploads/2020/10/test-tank-768x512.jpg 768w, https://cdn.navalapp.com/uploads/2020/10/test-tank-624x416.jpg 624w" />

Hull model being tested in a test tank.

What is the Froude number?

<img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' data-srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' height='80' width='80' data-src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' class='avatar avatar-80 photo lazyload' src='data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' /><noscript><img alt='' src='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg' srcset='https://navalapp.com/snp-wp-content/uploads/avatars/78/645e5dfdf1a99-bpthumb.jpg 2x' class='avatar avatar-80 photo' height='80' width='80' />

Topics: Hull | Hydrodynamics | Pablo Sopelana | Resistance | Wave-making resistance