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Discussion Starter · #1 ·
I want to hear all the in and outs of deadrise. I'd like someone to start by explaining just exactly what it is and then go into the benefits of a steeper deadrise versus a larger angle.

This is for my benefit as I research boats. I can't figure out why they make different hulls. It seems that a 16 degree deadrise that would work well in the ocean should also work well in the rivers. Or, does it have something to do with the draft. (it makes sense that a hull with an "ocean" deadrise would have more of a draft due to Archimedes Principle.) I'm not really trying to overanalyze but am very curious about this stuff. (I am an engineering student)

So, Let's hear it!

[ 09-01-2003, 11:41 PM: Message edited by: ScottyV ]
 

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Discussion Starter · #2 ·
Yeah, I got the general understanding. I am going to have to experience some different types though. I am curious what is the difference in draft? I want a boat that will venture out into the ocean but is primarily a river boat. I really like the Hewescraft 18" sportsman.

I can't figure out why ocean hulls that have a really steep deadrise are desired. They are great when you are underpower and headed straight into the swell but the second you take one on the side WOOHOO, are you going to roll. It also seams that a steeper deadrise is more likely to rtake water over the bow.
 

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Might want to look at the 18" sportsmans bigger brother, if you plan to go over the bar. I think you can trust the engineers from most any of the manufacturers....check their sled hulls, and their salt water hulls. North River Seahawk is a prime example, as is Willies Asaltor. CHeck their web pages to see what they say about them. THe beam,and the dead rise both figure into stability. Most boats with deeper vee's tend to be a bit wider to alleviate the roll. Russ
 

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The general rule is "the more deadrise you have, the better the ride". However, more deadrise, especially on a narrower boat can translate to less stability. I don't want to be a name dropper on boat brands, but for those of you going to the big water, you should also look at the Weldcraft Mavericks. They have a deep vee (18* at the transom and it tapers towards the hull for a deeper vee), yet they are very stable because they have built a reverse chine built into the hull similar to what you will find on a fiberglass boat. It rides MUCH BETTER than a regular deep vee aluminum when cornering in rough water or approaching rough water from less than a 90* angle. Ride in one in choppy water and compare it to a regular or even deep vee welded model without the chine, and you will be a believer.

ALMOST ALL fiberglass manufacturers and several aluminum manufacturers (Lund, Crestliner, Smokercraft, etc.) have been using a reverse chine for years to add stability and performance to a deep vee hull. The obvious reason why we haven't seen it on welded aluminum boats is for the simple fact that the thicker aluminum is more difficult to work with. Also, there has not been enough consumer demand for hull innovation. As far as I know, Weldcraft is the first to offer it. Duckworth is coming out with it for 2004. I would expect to see several manufacturers offering it in the years to come. (Hopefully, they will also start giving us wider bottoms).

Good luck in your search.

Dan
 

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The steeper the deadrise the better it cuts through the waves, the more it rocks, the flater the more stable it rides and the less draft. It all depends on the use of your boat, shallow water, rough ride or big water, smoother ride.
 

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I think most of what is said here is great stuff. However if you were to but an 18 degree boat and put a pump on it, you will most likely be unhappy with it's performance.

If the boat rides on a delta pad the story may change. but if the hull is 18 degrees at the pump, it will cavitate pretty bad.

With a prop, things are just fine.

Good thread.

Mark and the dog.
 

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Willie Raptor...Simply The Best. :grin: Pillow soft ride and butt-kickin'performance. Not a bad fishing boat, either! :dance:

SloTroll
 

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Talk to 5 different boat owners and...

My Willie Predator is 21 1/2'. My buddies is 22 1/2. One thing is any boat over 20' does not require internal floatation (foam) which eventually becomes waterlogged and really nasty with salt water. So for that reason, I'd stay over 20'.

Next, nothing rides shallower than a flat bottom, nothing rides smoother in chop than a deep Vee.

Everyone wants the best of both.

I can tell you this. If you want to run shallow, weight is a BIG factor. Also everyone gets geared up about how shallow their boat runs when WF open. Realistically, you cannot run WFO all the time. Run downstream through some nasty boulder patches and you'll see that how shallow your boat will run at 1/2 throttle is a more realistic requirement. I know my boat will pass a lot of places where straighter sided, heavier boats will hit (real world observation).

Last week in the estuary (bouy 10) it was choppy to down right rough. My boat does "pretty good" in those conditions. The heavier higher sided boats are smoother, and a little dryer.

I can run rivers like the Clack and NFL and Cowlitz in late summer conditions ALMOST as good as a flat bottom. In flat water the lower flared sides are nice for scooping fish.

Some boats gather water under the boat and lift the boat. BTW, My boat is 10 degrees at the transom, seldom ever cavitates, and side drifts just fine.

Pay close attention to how deep you sit at idle, and half throttle.

[ 09-03-2003, 03:10 PM: Message edited by: Gun Rod Bow ]
 

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Yes, the shallower deadrise does have a shallower draft as well, but the main reason why "sleds" go to the shallower deadrise is for the pump intake. You require a good laminar flow (check your Renalds number) across the pump intake, or else you cavitate the impeller.

You also mentioned about having V-hull not being so good when turning. A couple of the manufacturers also offer something called a radius bottom. I believe that BoiceJet has the best design. This radius bottom keeps the boat on a plain (actually rises in the water) better while cornering. The reverse chines you mentioned are appearing on more and more of the sled type of boats. I know for a fact that the BoiceJet has this feature as well.
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Radius Bottom - Boice Jet Exclusive High Performance Design
• High Flow Intake - Exclusive Boice Jet - Hand Crafted Radius Intake
• Wave Cutter Bow for Smooth Ride in Whitewater and Windchop
• Reverse Chine w/ Heavy Duty Slotted Extrusion
• Positive Lift Turning/Planing Strakes – Set of 6
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If you are looking at something primarily for the river, but can take it in the ocean *some*, then sled's fit that catagory well. Just keep asking questions, shop around, and go for lot's of boat rides. You probably can schedule lots of test rides during the boat show in January (?).
 
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