I have a question on the use of a boat?

[thudpucker]

I've seen in photos a small boat with a raised stern. Rounded on the end, but raised up from the water line.
This boat has a Prow, sail or engine, and of course all the old ones were plank.

Why the raised Stern?
What was that feature for?
Is is gone because other boats were better?
What do you know?

[daiquiri]

Can we see the photo you have seen?

[thudpucker]

Sorry for the delay. I just couldnt find a photo when I wanted one.
I got this link from our site. Its showing the kind of stern I'm talking about.

http://www.1906-twelvemetre.com/phot...y.html#gallery

[thudpucker]

here's some more photos.

This is a model of a boat with the stern I'm asking about.
Here's another photo and drawing showing that rounded uplifted stern.

[PAR]

That's an elliptical stern shown and one of my favorites. It's original intention was to permit nets and other "gear", to be hauled over the stern or aft quarters without fouling the corners, of a more traditional transom. It also has the benefit of providing more hull volume aft, so you get more deck space and on craft large enough to realize it, more aft cabin volume.

The flat transom you see on most boats is used because it's easy to build. A curved transom is a little harder, an elliptical harder still. There are a number of stern shapes, most have a specific reason for them. Such as the reversed transom seen on sailboats (this transom slopes toward the bow), this feature saves weight at a particularly important area in a sailboat. The same could be said of torpedo sterns, seen on old powerboats, to move unnecessary weight off the stern.

[thudpucker]

Good on ya PAR. You have a good understanding of your project.

I wonder if the "eliptical" stern would have the ability to temper the waves coming from the stern or stern quarter?
It seems like it would.

And out on the birney deep, would the ship tend to rock bow to stern in a mild Sea?

How about turning the boat? Would that hi-float stern be likely to skid or deepen the turn?
And in a following sea, would the stern bouyency tend to do its own steering by lifting the stern way past the center line of the direction, leaving the bow dug in and heading the wrong direction.

These are just questions. That kind of construction looks so useful I have thought of re-creating it in a 15' boat for lake fishing.

[Landlubber]

Transom shape is also determined by the conditions under which the vessel is designed to work, basically as PAR says, but not necesarily for fishing purposes. Boats crossing tidal bars should not have large flat transoms or they risk being broached by the incoming waves, here the canoe stern works well, the waves are parted without taking the boat as well, sea waves travel at 15 to 17 knots, as they approach shallows they tend to break, and doing that over your transom can ruin the entire day.
If the boat is taken by the waves the rudder becomes useless, so it is better to be faster than the waves or not be caught by them.

[thudpucker]

"...as they approach shallows they tend to break, and doing that over your transom can ruin the entire day."


Landlubber I've had the pleasure. It's a long story for a Campfire some night though.

How about my idea of using it for a lake boat?
A 15' flat or wide bottom boat, with a small motor (9.9 or less) with the idea that it could be rowed as well as trolled and would be stable to move around inside, without tipping or skidding out from underneath my feet?

[PAR]

The ability of a yacht to handle following seas or breaking waves is more a function of underwater shapes, then transom configuration.

Most elliptical transom designs are a double ended hull under the LWL. The same is true of many boats with a counter transom. Now, there are transom stern craft that have a barn door hanging off the butt of the boat, which isn't good for much of anything other then hull volume aft.

Without getting into the double ended or transom stern debate, most ill manners displayed by transom stern vessels are a result of shallow, light weight hulls, with triangular water planes. These shapes are fast, but can be nearly imposable to handle in some conditions, like those listed above. If the waterlines are reasonably balanced and the buttocks don't have a hard "tuck" at the aft end of the LWL, then it'll likely handle easily, regardless of it's stern configuration.

You'll find that a well designed hull can carry just about any shaped transom and handle just fine, including following seas and breaking surf.

Regarding the hull above, though the image is difficult to see, the type I'm pretty familiar with and it's got a lot of "sweetness" in the aft sections. By this I mean she's built way down to the bottom of her stern post, lots of reverse in her garboards and a gentle run. This would be a very sea kingly craft at the very moderate S/L ratios she's designed to travel at.

Her maneuverability would be limited as she's a straight shaft craft with a rudder and lots of deadwood. She'd want to track very well in a straight line, turning would require some way on and a patient skipper. In tight quarters she'd struggle without a bow thruster and/or twin screws. Which is just great for long hauls across a harbor or river and appears her original intent.

Without seeing her sections, I'd be hesitant to speculate on handling in following seas, but I suspect the stern is high enough off the water that most will part at the LWL and wrap around the hull cleanly. Yes, the stern has some buoyancy, but in the protected waters it's intended for, not a big issue, especially with that well immersed keel and rudder.

This shape wouldn't reduce down to 15' very well. It particularly wouldn't row well. Nor would your idea of a "wide bottom boat". Boats that row well need to be light weight, so fancy sterns and deadwood are out of the question. They also need to be narrow generally, with enough rocker to permit some maneuverability without being a hindrance to performance. You could have an elliptical stern row boat (I have several designs like this) that was flat bottomed or V bottomed, but it wouldn't be the built down style seen above. It would be more like that seen on a sharpie.

[thudpucker]

PAR your a good man! No matter what your Girlfriend says about you...LOL.
I knew you'd have the logical reasons why my Idea wouldnt work.
It just looked good to me, so I thought I'd ask the experts.

In Cook Inlet AK, they fish right off the beach. Sometimes its a long trip home across a 45 degree sea.
Those boats with the deep skeg are just about impossible to turn in to, and away from, the large waves.

But they will go right up on the beach, even in a high sea and land without shipping a lot of water over the stern. That water always comes with Sand and gravel.

I had a problem and had to go into the beach on a high sea day. When the bow hit, the stern swung around just a bit, and the following wave dumped into the boat. Most of my loose stuff went out with the swoosh of water and I had to abandon the boat and go chase my stuff.
I spent a few hours drying my clothes and bailing the boat.
It was that trip that I wished I had one of those big 'Barn Door' sterns.

Now that I see the logic of the eliptical stern and see that its for larger craft, I'll just go back to lurking again. Thanks.