The boat I have in mind would be similar to a
viking knorr.
How long would it take for a boat like that to sink if 3-5 men start chopping at the bottom with axes? Is it wobbly enough that the crew could capsize it by moving the sarcophagus and maybe some other cargo up against the bulwark?
A Viking knarr doesn't have a hold or upper deck. It's an open ship with some decking just above the bilge.
You'd have to lift the decking and chop holes in the hull. How fast the ship would sink depends on how fast the water comes in (how big the holes are).
However, Viking knarrs are made of wood, which floats. To actually sink the ship, the sarcophagus would need to be heavier than the floating capacity of the wood.
When we sink our Viking ship to protect it from hurricanes, it floats with the top strake and gunwale above the water. Our ship has far less floating capacity than a knarr.
I used to sail a lot, this is on a small boat but the principle is the same for a ship. Run straight across a very brisk wind and bring all your sails so they're flat to the wind, the wind catches the sails and the whole thing tips over very quickly if the wind is strong enough.
A knarr is a rather large ship. Longer and wider than our 40 foot x 12 food longship. Also, there's only one "square" (usually rectangular) sail. Given the inherent stability of the hull design, a much shorter mast height, and far lighter weight of sail, I would doubt that this manoever would reliably work with a knarr.
Also, even if you could capsize the ship, it wouldn't sink readily. See above. There's very little ballast in a Knarr. The sarcophagus would provide some ballast but it would have to be really heavy to offset the buoyancy of that much wood.
Where is the sarcophagus stowed? If it is in the hold,
No hold in a knarr.
That might be too much work, because there would be ribs and maybe the keel to chop through. They might be able to get a huge hole, but the water would make it impossible for them to finish chopping through. The ship would sink around the time when the water got too deep for them to chop the planking any more.
Good points. The Keel on a knarr is no wimpy thing. It's big. It runs the entire length of the ship. It would be difficult to chop through (in two places). Plus, as you say, there would be the framing to get through. And all those iron nails holding the planks together.
Maybe there's an auger in the carpenter's tool-chest? Bore a hole or two and get while the getting's good? Or maybe attack a strake along the waterline. Knorrs weren't very big, so I'm not sure you'd need a massive hole to flood it. That is ticklish business, scuttling a ship while one is still on it.
If the OP is also using Viking age technology, they did not have the inclined plane. To bore holes, they used what was basically a sharpened spoon. (Spoon bit.) Takes a while. An axe would be better and if there are Viking-armed fighters on the knarr, there would be axes.
There isn't much you can do to make a sailboat go faster. You can add more sail, but not with this sail plan, unless you have a reef in the sail.
Knars are single-masted, single sail ships. You can't add more sail unless, as you said, they'd taken a reef.
So the next option is to lighten the boat. You start throwing everything you can overboard. Obviously the easiest stuff goes first, and you tend to throw it over the leeward side of the boat (which will be a bit lower because of the ship's heel). Based upon what I can discover, these ships carried about 20 - 25 tons of freight. My guess is between fully laden and empty you'd probably see about a 20% or more increase in speed.
Yup. Depends on their freight. If this is an expedition of armed folks making off with the sarcophagus, they probably don't have a lot of cargo outside of it and their weapons. What do you say, efreysson?
Just occurred to me. Is this a stone sarcophagus? If it's wood, it will float, too, probably. They could throw over the stone lid. That ought to be pretty heavy. Can they throw over the
contents of the thing?
Now if you look at the model, you'll notice that there are several ropes that hold up the mast, which are called stays. When you are sailing, some of the stays are loaded, and bearing the mast's pull, and other stays aren't loaded. Roughly speaking, the loaded stays are going to be to windward. The leeward stays will be doing nothing, and will actually be loose.
No block and tackle on a knarr using Viking era technology. No need. The sail and yard don't weigh that much. But the standing rigging (stays that hold up the mast) is going to get in the way of heaving the sarcophagus over. So getting rid of them would be a good thing if you want to tip it overboard.
Result is your mast goes over the side.
Oh,
that would be fun. We broke our mast once. Not fun at all at the time.
They could always start a fire in the hold. Lamp oil, tar-soaked ropes, timber...
No hold. Also, the bits you want to burn are below the water line. Hard for a flame to keep going.
Seriously, can they just toss the thing overboard? Open vessels like a Knorr sink quickly, no air pockets. Unless it's made of something that floats of course.
Like wood?
