I'd think it might require water sloshing forward to force the lower buoyancy bows down, but I don't really know.
I asked chatGPT about this and it said if you fill and yacht with a hose pipe, it would sink level. The loss of buoyancy would occur uniformly across the volume of the boat. If it sat level normally, it would fill and sink level. It confirmed what I thought.
Chat GTP will tell you what you want to hear unfortunately ... here's what it told me ...
1.
Trimming dynamics: Even a slight forward trim causes water to flow downhill inside the boat.
Internal structure: Cabins, sole (floor), and bilge passages often let water flow more easily forward than aft.
Pitching motion: As the boat pitches in waves, water “sloshes” forward, and because the bow is narrower and deeper, it collects there.
2.
3.
4.
Summary:
Maybe. I just asked what would happen if you filled with a hose. It depends what you asked itChat GTP will tell you what you want to hear unfortunately ... here's what it told me ...
Water inside a flooded hull doesn’t stay where it entered — it flows forward due to several combined effects:
Result: Even if the hole is in the stern, the water often ends up pooling in the bow, shifting the center of gravity forward.
Even if flooding begins aft, the factors that cause bow-first sinking still exist:
- Heavy bow gear (anchor, chain, water tanks, sail locker) means the forward section is already weight-biased.
- Fine bow sections have less reserve buoyancy, so a small weight increase causes a larger draft increase.
- The stern’s fuller shape gives it more buoyancy, so it resists submerging longer — even with some flooding.
Once water sloshes forward and adds to that weight, the bow “takes over” and dives.
As the boat floods, its pitch behavior changes:
- Every wave lifts the stern more than the bow (because the stern is broader), nudging water forward.
- The mast and rig are slightly forward of the center of buoyancy — adding to the bow-down pitch once flooding reduces stability.
This creates a self-reinforcing cycle: forward flooding → bow trims down → more water flows forward → more bow-down trim.
Ironically, the stern can trap air bubbles in lockers, engine compartments, and cockpit voids. This “air cushion” buys it extra buoyancy compared to the flooded bow. So even if water enters from the back, the stern may float longer — and the bow still goes first.
Even when water enters through the stern (like from a broken rudder or transom breach), the internal flow of water forward, existing weight distribution, hull shape, and buoyancy dynamics all conspire to make the bow heavier first. The result: bow-first sinking is still the most likely outcome, even if the flooding starts aft.
The problem with chat GPT is that if you seed it with an assumption, it will search for answers to agree with your assumption ... the question I asked it was ...
SummaryYeh, thats pretty much what I thought in a static situation, but with water sloshing backwards and forwards the dynamic situation might be different and force the bows down.
I am really glad we avoided the whole area and sailed straight to Madiera. That way I didn't need to post the results of which way we sank on hereThe problem with chat GPT is that if you seed it with an assumption, it will search for answers to agree with your assumption ... the question I asked it was ...
"Why do modern cruising boats sailboats sink bows first even when the water enters at the rear due to a broken rudder?"
... so it told me how this can happen, and it wasn't wrong.
So next if you ask it ...
Why do modern cruising sailboats sink stern first?
ChatGPT said:
Ah! Now this is the opposite scenario—modern cruising sailboats sinking stern first. Let’s break it down carefully, because it depends on hull design, weight distribution, and how flooding occurs.
1.
- Modern cruising sailboats often carry heavy equipment in the stern: engines, fuel tanks, water tanks, batteries, and sometimes dinghies on davits.
- If flooding starts in the stern (cockpit, transom leak, broken rudder, etc.), the additional water adds to the existing aft weight, causing the stern to settle lower in the water first.
2.
- Many modern boats have wide, flat sterns for planing, cockpit space, and interior volume.
- While broad sterns are initially buoyant, once they start to flood, the large flat area allows water to spread, reducing buoyancy quickly and causing stern-down trim.
3.
- Cockpits in modern cruising boats are often self-bailing, but if they fail or the transom is compromised (broken rudder, transom leak), water can enter rapidly.
- Since water collects aft first, it can’t escape quickly enough, tipping the stern down.
4.
- Water entering the stern can slosh forward and sideways, but on many modern designs, the cockpit is deep and aft, so the free surface effect is concentrated in the stern, amplifying stern-down trim.
5.
- If the boat is moving, heeling, or pitching, stern-down sinking can be worse because water in the aft cockpit pushes the stern lower, and the bow may rise slightly initially.
Modern cruising sailboats sink stern first when flooding starts aft because:
Once the stern floods past a critical point, the bow may rise, and the boat can “poop deck” (stern-heavy, bow raised) before eventual capsizing or sinking.
- Heavy weight concentrated aft (engine, tanks, gear).
- Wide, flat stern collects water quickly.
- Cockpit/transom flooding overwhelms self-bailing features.
- Free surface effect amplifies stern trim.
The only conclusion is that both are possible and there are reasons for both, my take is that it depends on the specific weight distribution and resultant trim of the boat in question. Water will flow to the lowest point in the hull, and this process is self-reinforcing which results in a random outcome - especially when you add motion of the sea to the equation.
The well recognised but not too publiced deterrent method is large fire crackers that have chemical fuses. The Spanish and Portuguese fishermen use them again orcas. They tape a rock to them and throw them over the side. They make a hell of a noise and it works. No damage to the orcas apart from a headache and no boat damage.
I'm not sure, but I think you need a licence for spear gun /harpoon in Spanish waters.
In Portugal you need a license to fish with a speargun. Owning one is not an offense. I suspect Spain is similar. Just for info. I doubt I could even hit an Orca from the stern of my boat jet alone do it any serious harm. You'd have to be pretty close I would think. And if you did and you annoyed it?????????????
You can buy easily in Spain but not in Portugal.
In Spain I think you need a licence to purchase, use or transport.....
I suppose hearing damage, potentially serious for an acoustically sophisticated animal, might be a possibility. Maybe start with a small squib and only escalate to a big one if necessary?
You mean when your rudder is hanging off after the first bite or two?
Nah! Use the biggest you've got. Why give it time for another bite of your rudder.
We don't need to kill them or do serious injury. Scaring them away works for the fishermen. It should work fine for yachties. If every boat they approached did the same, they wouldn't approach boats