Splitting Waves and Hairs: Comparing X-bow, Axe Bow, and More

[@maddun3700]

Thanks Nick. Another excellent video, I learned a lot. As usual you deliver the right amount of infomation for a layman like myself to understand without being too technical or too simplistic.

[@jpstenino]

well said

[@swimspud]

I’ve been curious about why we see different bow types for a while. Thanks for the awesome and in-depth discussion

[@darrellbedford9925]

The axe bow reminds me of what was called "Destroyer Bow" as used on military destroyers of old.

[@cobrasvt347]

Or the Titanic’s bow. lol

[@Orvz475]

I think the Iowa-Class Fast Battleships also had the Axe Bow as well.

[@TheWizardGamez]

Whale wars has like 80 of those Damon shipyard axe bow vessels

[@StaK_1980]

@@Orvz475 NO, the Iowa has a classic bow. One could even say a clipper bow.

[@roadboat9216]

Yes, I served on a wwII era destroyer. Man that was not much fun in really heavy weather. And we saw plenty. We killed 3 men and injured several more and put several over the side while going out an inlet in Taiwan. The force of the waves severely bent the steel ladders going up the sides of the superstructure. The ladders were SIDEWAYS to the water flow. Really bad call to have men on the bow in these conditions. He lost his ticket on that one.

[@philipteevee8067]

I'm not even really into boats and I find this channel fascinating! I'm already mentally designing a hypothetical tri-hull swath, but with a aft-biased centre of gravity and with a wider structural section rising from the forward part of the submerged swath pods to improve seakeeping, with wave piercing tips to the three hulls, resulting in a W-shaped planform.... lol, I've only the barest idea of what I'm talking about, but what I do know is thanks to the channel, and it's fun to think about!

[@erikig]

“I’m not even really into boats”…🤣

[@mikewalrus4763]

From my small experience at sea - deck hand to master over 37 years, sadly I find that Marine Architects and the ships crew are at different ends of the spectrum - rarely do the two meet (a bit like shore side architects and builders) on the one side the architect designs grandiose shapes on the other side both crews and builders put themselves at risk to either operate or build these designs. despite that I would like to congratulate the presenter for at least looking at both sides of the coin. Very well done sir, we are finally getting somewhere, let us hope others will move that way too (I do of course include ships crews who often complain as a matter of course despite the efforts of the architect)

[@OgamiItto70]

To be fair, a naval architect who goes to sea exposes him or herself to danger, wet, cold, heat and seasickness. Horrors!

[@mikewalrus4763]

@@OgamiItto70 Just a minute - the idea of being a so called Naval Architect is to design things that go to sea! This means that the naval architect should have some idea of what he's doing, this can only be got at sea! If you were such a being I certainly wouldn't buy any of your designs nor go anywhere on one of them!

[@OgamiItto70]

@@mikewalrus4763 Yeah, but heating, air conditioning, supermarkets, bars, restaurants, bookstores, coffee shops, movie theaters, bowling alleys, female women of the opposite sex...all in much greater, more reliable supply ashore than at sea!

[@mikewalrus4763]

@@OgamiItto70 What has that got to do with designing sea going vessels other than the fact that some or all of it may be required at sea? Or at least facitities for and to use such items

[@OgamiItto70]

@@mikewalrus4763 Cost/benefit analysis for college boys or girls.

[@jshrawder49]

That was a great great video thank you for going through this information in a very simple way in English!!! Keep up the great videos!!!

[@skyak4493]

Nick, this is the best video I have seen on the subject. As they say "a picture is worth a thousand words" this video is worth 10X the thousands of blog posts I have seen bouncing this topic around and never achieving any resolution. I think your insights on attributes are all true, but you stop short of putting numbers and dimensions on these concepts. Wave height capacity and frequency response would make deciding on a bow design clear and simple. I know that as a professional you can't give away all your secrets, but I have seen so many NAs insisting that this is a mystical process I think you could clean up as the guy who makes this a clear and simple optimization. All these bows have a wave height capacity with varying negative consequences from exceeding that capacity. Wave height from the ships perspective is wave height apparent, which is a function of incident frequency which is a function of ship speed, wave incidence, and ship heave natural frequency. You don't even have to be a genius to know what the expensive CFD studies are going to find.

[@nauticalwolf6649]

I like your energy and how you explain things in a way a layman can grasp. Keep it up!

[@RikMaxSpeed]

Thank you for providing clear reasoned explanations as opposed to the marketing waffle I’ve seen on other videos.

[@yoghik]

What a great man! As a yacht designer I found out a tonn of usefull information here!!! Grand thanks!

[@awmperry]

Fascinating. I've just been trying to explain to someone the difference between a plumb bow, a straight-stem bow, an axe bow and an X-bow - this will be very useful in clarifying it.

[@sterlingabbot695]

Was about to go boat shopping. Good thing I ran into your video.

[@mikeperth8027]

Great and very informative video. Thank you for taking the time to make it and for the free lesson on hull shapes.

[@kristianblazevic2008]

hey just to make clear when you find yourself in a storm no matter what type of ship you have its not easy trust me Think for every thing you want from amazon or ebay someone need to shipp it across the world thik about people stuck on shipps because of Covid

[@paulmcmullan9931]

I would be intrigued to know about the often backward racked bow of a dreadnought class battleship and zumwalt class destroyer.

[@RockitMan-ey8tx]

I truly enjoy your video lectures. Most interesting.

[@MrOlgrumpy]

The AXE bow dates back more than a century

[@semersion]

Super cool video! Thank you very much. Subscribed and cant wait to see more. It got me to thinking about the affects of these bows when you have a following sea.

[@predator1739]

I want to know which X-BOW is suitable for a small cruising sailing yacht about 20 meters long? The priority is to reduce the comfort of the pitch movement and the efficiency of the drive. thx！

[@benthompson2205]

I have nothing to do with ships, boats, yachts, hulls or anything, but I still found this interesting.

[@uwootmviii8695]

so, i saw the video of the thunderchild II and damn, thats an interesting entry in this whole bow form theme, i like it.

[@JoeC88]

Thanks for the excellent presentation

[@damieno224]

Hey Nicholas, just discovered your awesome channel. So far i've neglected the outboard swap in my driveway for 4hrs and counting....all because of curiousity and hunger for knowledge on anything nautical, but particularly design theory and concepts that can (or have been) measured in real-world application. 4hrs and counting.... Anyway, regarding bow designs, I'm interested to see your take on some more unconventional builds, in particular: A) the Seaski boats, B) how hydrofoils in general are seemingly being embraced in the sailing world, but dismissed as "tried that, too hard" in power boats. The exception being the 'wake/wave' damping foils more recently fitted to to some large ships with apparent success. cheers

[@DatawaveMarineSolutions]

I read Seaski's explanation behind their vessel: www.seaski.com.au/portfolio_page/about/ . It apparently uses a combination of two planing hulls on the sides and compressed air under the hull for lift. I have seen this concept before. I'm not sure how well the air under the hull works. That is an area that I need to personally research further. But the side planing hulls should work just fine. The only downside to the whole hull is that I would not trust that with any large waves of 1.5 - 2 m wave height. The same hull design that compresses air will also create huge pitch motions on a hull. I need to make a whole video on hydrofoils. But for the short explanation: It's important to remember that hydrofoils in the sailing world are only going on high performance racing vessels. The people that use those boats are highly experienced sailors, who want a bigger challenge. And hydrofoils are a challenge. On a normal boat, you only need to worry about your direction of travel (yaw motion control). The ship's hull handles motion control in all your other degrees of freedom (surge, sway, heave, roll, and pitch). But a hydrofoil needs motion control for all six degrees of freedom. Either very attentive crew, or an autopilot more suited to an airplane. That is the main challenge of hydrofoils: you need to worry about controlling all six degrees of freedom.

[@martinhealy2902]

Thanks for the information and your teaching it! Appreciated!

[@DarkShroom]

wow amazing channel.... citations omg this is great u really don't waste any of people's time in this presentation, tight and to the point, it feels great when you find a channel you know you're learn something from

[@thevirginclanlee275]

Very good presentation. I think the X bow is the future trend, way better than others.

[@geraldhoag5548]

I have seen videos on youtube that show an x-bow next to a conventional bow of oilfield service ships in the north sea and notices that the x-bow had less pitching. This seems to me to cause the thrust from the props to remain more horizontal. This will make the thrust more efficient, improving effective thrust, improving fuel economy, or reducing thrust requirement to maintain a given speed.

[@RovingPunster]

Great explanation.

[@PartisanOgrae]

Thanks for sharing this!

[@Andy_M986]

There is a video of an X bow going through the waves, alongside a normal bow ship,the video shows the X bow cruising through the waves with ease,while the normal.bow would rise up and slam down.

[@danielmartin7838]

I was driving down a rural road at 50 one morning and hit some water on the road. It reduced the speed of my Land Rover down to 30mph. Quite fun

[@mudchair16]

Look into my eyes, look into my eyes Not around out the eyes, don't look around the eyes Look into my eyes You're under

[@MartyInTheWoods]

👍👍👍 Thank you Schlomo!!! You saved hours for me trying to find out what that guy reminded me off! Brilliant! 👍👍👍

[@RovingPunster]

(Drools aimlessly, half hypn ....)

[@archularal49]

I loved it, it was better than Cats, I will see it again and again.....

[@geomardomingo1672]

I was NOT ready for the class.

[@gsmith207]

Thanks for the education. Learned something new today. Love that!

[@budsbustbi6339]

slight broaching?? the one i worked on would broach just thinking about a following sea!!

[@christopherpardell4418]

I think the long bow is simply moving the personnel spaces toward the center of pitch rotation. That is, the tip of the bow experiences the same high accelerations, because it is moving up and down a significant distance... but the crew spaces are at or near the center of that rotation and simply move a shorter distance in the same period.

[@Torvikholm]

I remember the launch of the first x-bow vessel, the Bourbon Ocra. I was allowed onboard for a look around. I found it incredibly wired looking. And to be honest, I still do. I don't work at sea myself, but what I hear is that the x-bow is stable with sea straight on, but is uncomfortable with waves hitting from a 45 degree angle.

[@TheTiacat]

I can’t believe this held my limited attention span for 20 min. Really neat. I actually learned something watching KZbin.

[@davidodonovan1699]

Thank you for this information

[@d.josephvirnig764]

Hi Nick, thanks for teaching me today! I am into a project you may find interesting; I am refitting a 100' wooden tug (keel laid in '25 for Wrigley by Muller in San Jose) into a mini cruise ship. She has a plumb prow, beamy midships, deep draft, big wheel and fan tail. My name is Dj, I am on her in the Salsh Sea.

[@chloehennessey6813]

My grandpa named one of their new X now ships after me. She services oil rigs in the North Sea. My father named our newest 300T bollard pull seagoing tug the nickname he has for me.

[@bibaswansarkar7206]

A lucky lady :)

[@BillyRillkratz]

Who wants to know? Only your ego.

[@lewisdoherty7621]

I remember as a kid looking at the old photographs of the dreadnoughts with inverted bows. Now they are back for some new warships.

[@espressomessiah]

That video embedded in this video is a New Zealand navy ship in the sub antarctic ocean. Big waves, growlers and bergy bits!

[@adamnorton748]

Thanks for sharing. Good explanations

[@NighthawkNZ]

HMNZS Otago in rough sea in the southern ocean... ahhh the memories..

[@mlight6845]

Excellent video about mechanics of bow design. I just discovered the wave splitting hull catamaran and wondered how well they do as the size of the wave increases. Lots of green water. Thank you!

[@ghostindamachine]

Super interesting!

[@ph11p3540]

Good stuff. Now I understand why the Zumwalt class destroyers are having some minor structural issues in front of the super structure and why the advanced gun system is having reliability issues.

[@gregwarner3753]

Although I have had far less experience on blue water than Master Walrus, I have been on the deep water on Navy ships as a WW2 Liberty ship, a deep sea salvage tug, another WW2 Destroyer and a WW2 Destroyer Escort. The interesting characteristic of the Liberty ship was it would pull the top of the propellor out of the water in moderate 2 to 3 meter head seas. The partially unloaded prop would shake the entire ship. The salvage tug, USS Preserver ARS-4, had a lot of top hamper and, because it was short and fat, managed to combine pitch, roll and yaw in most interesting ways. I estimated the bow would pull at least half a G upward acelleration pitching in a heavy sea. Eating became intermittent much of the time. The Destroyer was sensitive in roll and not all that bad in pitch and yaw. No all that bad in the aforementioned 2 to 3 meter seas. 4 to 5 meter seas were another matter. Seasickness was just about guaranteed. The Destroyer Escort was ok in smooth water. Off the coast of Nova Scotia in January was a completely different matter. This thing pitched, rolled and yawed all the time and at the same time. I saw green water to the first gun mount on that cruise. Being below decks, I was a snipe, looking at an inclinometer was very disconcerting. I was too frightened to be seasick. I gained a tremendous respect for the sailors that took these things out into the winter Atlantic Ocean to escort convoys in every kind of weather. All of these ships had the "conventional" bow shapes that were either straight up or tilted forward.

[@d.c.t.munasinghekalupathir98]

èxcellant video Mr Nick

[@rabbitspliff]

Speak of the devil. I was just searching your channel for any vid on X-Bows yesterday. Consider this another well earned sub.

[@mboyer68]

The bulbous bow is designed to create two separate waves which in theory will cancel each other out, thus reducing drag, increasing fuel economy and top speed. It has to do with waterline and is known as theoretical hull speed. Surprised you didn't mention that. Working with CFD, or computational fluid dynamics, designers can create a computer model of a hull design and test it, very accurately, in that computer model.

[@wmayo1492]

Wouldn’t the reduced pitch motions and smoother ride both be beneficial when towing. As this is a major use for X-bow ships, if so, that would a benefit.

[@laprepper]

So had to look up mass on a rod moment of inertia, I = mr^2. In other words double the mass and you get double the moment of inertia, double the length of the boat and you get four times the mom of inertia. So a boat 2x as long won’t necessarily have 4x better resistance to pitching, it perhaps it points to designers focusing on length over weight as a stronger driver of resisting pitching moments

[@henningklaveness7082]

Hands down your best video yet. Especially your analysis of the X-bow was very informative. I find the balancing act of contradictory requirements in ship design extremely interesting, and wrestle with the idea of "the ideal hull" for my application, long range cruising. The interplay between transportation economy (speed x cargo mass / fuel usage) versus constructive cost and how the life cycle economy works out in different usage cases is complex enough, but it gets really interesting when you throw sea keeping requirements into the mix. Perhaps a subject for a future video? BTW, I was under the impression that the X-bow was more efficient when running at speed in heavy weather, which I find very thermodynamically intuitive since the sheets of green water represent a lower state of entropy than the foamy spray kicked up by a conventional bow.

[@DatawaveMarineSolutions]

It gets even more fun when we add in all the mechanical elements. For example, vibrations are a big concern on the ship for passenger and crew comfort. One of the main sources of vibration comes from interactions between the propeller and hull. So we often decide on separations between propeller and hull based on vibration concerns, rather than propeller efficiency.

[@henningklaveness7082]

Don't I know it. My current boat is roughly 13.5m LOA / 25 T displacement, and came with a 36" / 90 cm CPP in a poorly designed Kort nozzle. That configuration was bad enough to break windows under full power, but things improved immeasurably when I cut the nozzle off and re-ground the blade tips. With a 15 cm blade-to-hull clearance, I expect things to get almost nice once I re-locate all the ballast to the wedge keel that carries the shaft.

[@marshallgiuffria366]

Good video, there are some things that were shaken up, but I like them.

[@robertpapps3618]

Thanks for your presentation.

[@wingedmonkeys548]

Hello Nick , too bad there are no subtitles in French because your channel is really interesting! I had seen a report on how to create a hull from an imitation of animals, particularly sea animals. The X bow is interesting to know if a fish or a marine mammal has been copied!!

[@DatawaveMarineSolutions]

Not for the X-bow. That was developed by Ulstein, a shipyard out of Norway. They create a lot of ships to support the oil fields up in the North Atlantic, where the ocean has extremely violent waves. So the X-bow came from a change in design priorities. Most designers, we start by creating a bow shape with low resistance. Ulstein started by creating a bow shape with low pitching motions. And that's how the X-bow was born.

[@sjohnsneddon]

Great video footage from HMNZS Otago

[@harrie205]

nice video as a mechanical Engenieur and sailor i was thinking i had understood the bow types but you showed my that i was wrong and how it is in reality

[@MartyInTheWoods]

Prust, brilliant! I think, I peed myself... Thank you Harrie! (but honestly, I don't think he is serious, is he?)

[@DatawaveMarineSolutions]

@@MartyInTheWoods With over a decade experience as a professional naval architect, I better be serious. I admit that KZbin is not a platform where one expects to get taken seriously most of the time. But to set the record straight: not a joke. Actual useful information based on informed science and engineering.

[@Jesusisking2785]

I can say being on traditional ships it feels more like a ram in rough seas like smashing into it rather than slicing through it

[@zweispurmopped]

I guess you missed one point about the X-bow. Like the piercing bow, it offers little resistance to water running down its sides. In what seems to be known as green water events, this will permit the ship to develop a fairly high vertical speed rising through a wave, likely ultimately cutting through it. On the conventional bow, the water on deck will create a much greater resistance against pitching upwards. That makes me think that the X-bow will work very well in extreme conditions, and I would expect it to be pretty good at coping with freak waves.

[@BillyRillkratz]

That is indeed a necklace I am not at all jealous about.

[@deck614]

Please demonstrate, not only tell. X-Bows are, however, the reason why we all talk of new shapes for boats these days. Nobody bothered before - unless of course the bulb dating from the 30s (Paquebot Normandie). Your quest is interesting.

[@paxwallacejazz]

Being used as tugs. The hul shape under the ship provides a clear run to the giant props. It's a marine mammal death trap I fear. The suck into those props immense I would think.

[@thenavalarch]

Great! Super informative. Thanks

[@nicolasruiz6976]

Very interesting video, thanks! Now, I can't avoid thinking of the bows in canadian canoes which I guess are suitable for rivers and lakes (small and short waves). I would love to hear some comments on that.

[@dominictarrsailing]

hmm I think that may be largely the result of the traditional construction technique making the boat out of a sheet of tree bark. That's the bow shape that's easy to make.

[@bradyk8454]

Would you describe the wave piercer as a tumblehome?

[@jamesellsworth9673]

Would-be owners need to know this information in considering their priorities. Thank you.

[@mrarcher3580]

Bow-wow-wow-yippee-yo-yippee-yay The Sounds the dog bring me to another day nice video well done

[@jonpaton4449]

Might be tough to put a flight deck on that X-bow

[@navistars]

As they all look more or less the same, Will you recommend a different bow for an inflatable bot such is the Zodiac ones?

[@jamesward2276]

I think inclusion of SWATH designs might be a worthwhile addition.

[@DatawaveMarineSolutions]

You can find SWATH designs in my other video here: kzbin.info/www/bejne/oHukeax6oZt-iZo

[@jamesward2276]

@@DatawaveMarineSolutions watched it. Good job. As you stated, just like a cat - very smooth until the wave capability is exceeded and that green monster slams the flat underbelly! Have you done a comparison of anti-roll systems, e.g. gyros, wings/birds, active stabilizers, tuned water tanks, roll keels? I find rolling to be worse than pitch (slow displacement boats).

[@DatawaveMarineSolutions]

@@jamesward2276 Not yet. Eventually, I would like to do an entire series of videos on seakeeping and comparison of anti-roll systems.

[@OgamiItto70]

That conventional bow, with its rising flotation curve, can impart a motion to the vessel that is strenuous and fatiguing to the crew, but swimming is still more strenuous and fatiguing. Especially in cold waters. The X-Bow appears to lessen the tendency of the vessel to slow due to oncoming waves and moves the moment arm aft as the wave rises higher and higher up the hull, giving the crew a much smoother, more comfortable ride to the bottom of the ocean. Plus, it's ugly, an important feature of vessels like Great Lakes cargo haulers. The Axe Bow and Wave Piercer Bow appear to add greater speed to the "virtues" of the X-Bow. I did like how that "what happens if we just lengthen the bow?" study from Delft University started showing profiles that looked like Cigarette boats as their bows got longer and their weight became more concentrated aft, proportionally. "Good for planing hulls but, oh yeah, slamming," indeed.

[@davelowesky8054]

I thought the X Bow was specifically created to combat big waves

[@XtianApi]

Well, now I know which bow to choose. Ugh. I need to go to bed. Very interesting though

[@nickabel8279]

So which design is best for rogue waves/ open ocean very large waves?

[@tiomoidofangle102]

I am curious as to how the X-bow would work on a catamaran or trimaran.

[@sirinath]

How does the x-bow compare with SWATH?

[@ao341]

Can ask what program you are using to simulate the water flow between the conventional bow and the X bow? Does the program work with designs? Like if you designed your own bow, would simulate water flow around it? I appreciate the info and I truly enjoyed your video. I liked and subscribed. Thank you again stay safe.

[@coryyoung8289]

Amen Father! 🙏

[@Pilot4prophet661]

I can't agree with the criterion of a "smoother ride for the crew" as a design criteria for a working vessel. More appropriate would be an analysis on hull stress/life. Ships are built for war or trade, but cruising and entertaining are a vastly different mission. Haze Grey and Underway.

[@DragonReaver]

Well if the mission needs to have people on board that are not used to seafaring(landlubbers) or easily get seasick then I would say a more stable ship might be more useful if you need those people to not be throwing up all day.

[@robinj6997]

You mentioned X-bow could be more beneficial for larger vessels. I'm sketching on a small sailboat with a 5:1 LWL to beam ration; would the higher ratio be beneficial for this bow design?

[@DatawaveMarineSolutions]

Probably not. The X-bow depends on having an extremely high freeboard, well above regular wave height. A small sailboat can't achieve this. (It would require a bow near the same height as your mast.)

[@robinj6997]

Haha I don't want a bow that high, but I was thinking on height be the 1.2 of the beam. The Atlantic rowboats have a very similar design as the X-bow, and they are about the same size as the sailing vessel I'm sketching on.

[@agontop1]

Excellent Vid.. Thank you.

[@geronimo4511]

I wonder what happens all these various bow types when waves come from directions other than straight ahead?

[@ivansulovsky3248]

Love your work! suggestion for a topic - parametric rolling

[@davidgallagher171]

Outstanding!

[@NaomiClareNL]

Thanks Nicholas!

[@superfluous9726]

I love how he says "wall of solid water"

[@ronaldreed7698]

I'm 3/4 of the way through and didn't hear anything about speed concerning bow shapes, the primary purpose for the bulbous underwater portion of bows is to increase speed as is a plumb bow on sailboats. A wave piercing bow increases hull speed as does a plumb bow, bow shapes have a considerable effect on hull speed, the higher the hull speed the higher the vessels efficient speed, more speed for less fuel comparable to vessels with lower hull speed.

[@gaycha6589]

I thought it was a Fast Show sketch with John Thompson doing Jazz Club

[@Norwegian733]

Vikings used X- Bow 1000 years ago. The design is basically the same.

[@2adamast]

You mean those guys (team-)rowing smaller open deck vessels across the north sea or just 21st century fantasy?

[@fourtoes412]

Great video - I prefer the axe bow.

[@quillmaurer6563]

The biggest drawback it sounds like of the axe bow is that the length of ship is larger for a given amount of cargo or weight capacity. How does the modern axe bow concept compare to ships of the early 20th century that pretty much universally had nearly vertical stems - Titanic probably the most famous example, but almost all her contemporaries as well. Is that an axe bow, or something different? Why did they design them like that, what were the pros and cons? Why was that design nearly universal back then, but never seen anymore? I could imagine that maybe it was less efficient than the raked design, but if it had better seakeeping this would be more important for ocean liners than for modern cargo ships - yet modern cruise ships, which are even more comfort-focused, use the conventional raked bow as well. The largest ships of those times (Titanic and sisters) were small by modern standards, but even ships comparable to that size now use raked bows. Would be interesting to compare other designs through the centuries, from early designs to the more rounded bows of the Middle Ages, to the "conventional" bows of later sailing and early steamships (think of clipper ships), a trend of vertical stems in the late 19th/early 20th centuries, return to the "conventional" bow seen now, and the rise of the bulbous bow. Some of these "unconventional" designs, which for the most part are just small niches rather than mainstream. Think of factors like method of propulsion (sails vs. paddlewheel vs. propeller), construction methods, available hydrodynamics knowledge, and priorities of shipbuilders.

[@Hudsoncolo]

What about Tumblehome bows?

[@michaeljansz1969]

Is the Axe Bow you get in FRP?

[@koachs77]

Sea Shepards, use a wave piercing bow , or it did until it got hit , BB

[@rabbitspliff]

Ok now I've watched the video, I'll explain why I've been watching Naval Arch vids recently. I'm really into the aesthetics of the ships of the golden age of sail, from late 18th to mid/late 19th century, and I was wondering how the design of ships of that era, with sails as propulsion and the building methods and materials of that time, could be improved with the knowledge and modelling we have nowadays. In some of my reading I noticed how there was a shift between the galleons of the 16th/17th centuries, and the ships of the line of the 18th/19th. The rake of the bows was generally, as time progressed, reduced. The rationale behind it seemed to be to bring the LWL forward and closer to the LOA, bringing the hulls buoyancy forward and beneath a larger span of the deck. Since ships were built according to how many cannons they could fit on each deck, and thus deck length, and given cannons are heavy, it was seen as important to increase hull buoyancy beneath the decks to maximise how much of the deck could be used for guns. Also resultant from this was that the fore of these ships would tend to be pretty full, and not conducive to really cutting through waves. An additional design concern was regarding weatherliness. Especially important in wind propelled vessels is to minimise leeway, or being pushed off course by a side- or headwind. There was a push-and-pull between having enough freeboard to fit in gundecks, but not so much as to unnecessarily increase the surface area of freeboard and its susceptability to being blown off course. I had been looking at X-Bows thinking "what if they had been implemented in sail ships?" - after all, it would have continued a pattern of increasing the LWL towards the LOA, to the point where it seems X-Bows' LWL _is_ the LOA, it would potentially improve speed, and seakeeping. Alas, it would come with 2 major downsides for those ships of the line. The first is reducing the length of the decks, especially the top deck, that could be used for cannons. This was obvious to me before simply from the shape of the reverse rake, but also, as you noted, the fact that it shifts the buoyancy back as well. In all, I don't consider this the biggest problem. The biggest problem is weatherliness. The design seems to necessitate higher freeboard (and hey, why not just add another gun deck!?), but that obviously means the ship would suffer a lot more leeway. So if you dont mind me asking... how would you improve the bow design of an age of sail ship of the line?

[@rabbitspliff]

I still think it might have been feasible to X-Bow a 3 deck first rate.

[@rabbitspliff]

One other thing I feel I neglected to include in my textwall, kind of stating the obvious. The location of the means of propulsion on a sail ship, above deck rather than below the waterline at the back of the keel, creates moment which pushes the bow downwards, so I don't think slamming is ever a real problem for large tall sail ships.

[@DatawaveMarineSolutions]

That is a fun question. I'll limit myself to building techniques they could achieve in that era. One thing I would try is to add a free flooded fairing on the front of their buoyant volume. It would be open the sea and add no buoyancy. Just act as a fairing that sticks out underneath the bowsprit. That way you still get your full deck length. But the fairing reduces the water resistance and wave impacts. But it would have minimal effect on seakeeping. So the idea probably requires further refinement . . .

[@trivium8734]

This is so cool. Thanks man.

[@sgoheibhrin894]

A very interesting video. Unfortunately, in my experience, X-bows do little to reduce that "jerky" motion mentioned in the video (speaking of a 90m PSV).

[@stephenbritton9297]

What would you classify the USN DDG1000 class bow (besides fugly)? Wave piercing cross section with the large slab sided tumblehome, but then there's this giant sonar dome of a bulbous bow down there!