Dead rise and it's affect on handling

[Pakmule]

A sales guy that I was talking to was talking about the dead rise of the 310 and how it was at the limit of what could be done on a planing hull. I just nodded and smiled as I had no idea what he was talking about.

What exactly does dead rise mean and what affect does it have on handling?

 

[fwebster]

Deadrise is simply the angle at which the bottom is formed. Picture a cross section of a hull....if a boat had no deadrise, the bottom would be flat from chine to chine across the keel. A v-hull boat has deadrise and the angle is the amount of the angle from horizontal at which the bottom rises from the keel out to the chine. The steeper the deadrise the softer the hull will ride. At some point, however, as the angle of deadrise increases it get so great that the hull cannot plane efficiently.

This would e a lot easier to explain if I could draw a picture!

 

[Pakmule]

Deadrise is simply the angle at which the bottom is formed. Picture a cross section of a hull....if a boat had no deadrise, the bottom would be flat from chine to chine across the keel. A v-hull boat has deadrise and the angle is the amount of the angle from horizontal at which the bottom rises from the keel out to the chine. The steeper the deadrise the softer the hull will ride. At some point, however, as the angle of deadrise increases it get so great that the hull cannot plane efficiently.

This would e a lot easier to explain if I could draw a picture!

No need for a picture. I actually got it. So the salesman's point was that the 310 would be a very stable ride as it is as close to the planing limit as possible. Does mean that the that the 310 does not plane all that well?

 

[Sea Gull]

A boat with a high transom dead-rise angle will move well through water and handle waves. At rest they tend to bob like corks. Almost all boats have a modified V design where trade-offs are made between the benfits of deep v forward and a somewhat flattend V aft section.

 

[estebanj]

I wouldn't look too much into it. The 310 has 21 degree deadrise, which is high. Many boats have 16-18, but that doesn't mean they are bad.

The best way to use this info? Take a test drive on the 310 and see if you like how it cruises at slow RPMs and at cruising speed.

Esteban

 

[Pakmule]

I wouldn't look too much into it. The 310 has 21 degree deadrise, which is high. Many boats have 16-18, but that doesn't mean they are bad.

The best way to use this info? Take a test drive on the 310 and see if you like how it cruises at slow RPMs and at cruising speed.

Esteban

I plan on doing exactly that now that I have settled on the 310. My current boat search has brought me through several boats from the 270 all the way through the 310.

 

[fwebster]

The truth of the matter is that Sea Ray has this Sundancer thing figured out so well that they don't make bad boats. You probably couldn't tell a 21 degree deadrise from an 18 if you were to run 2 different boats. I tend to think that in this sized boat, the drive set up, how it is trimmed, and the presence and use of trim tabs make more difference than the hull form.

 

[Pakmule]

The truth of the matter is that Sea Ray has this Sundancer thing figured out so well that they don't make bad boats. You probably couldn't tell a 21 degree deadrise from an 18 if you were to run 2 different boats. I tend to think that in this sized boat, the drive set up, how it is trimmed, and the presence and use of trim tabs make more difference than the hull form.

Probably not as I am more than a little intimidated at trying to pilot a 310 when I have about ten hours on boats bigger than 22 feet and all my hours were on I/Os.

 

[Bridog]

Heres another thread... http://www.clubsearay.com/forums/viewtopic.php?t=1968&highlight=deadrise

 

[goblue]

The bigger the boat the less deadrise you need and fine entry becomes more important. Smaller boats in the 21-26 foot range benefit from more deadrise because they don't alway span the waves in bigger water and can pound easily. As I recall the 79 26 SR was more than the boat you describle--maybe 23 or 24 degrees. It was a good hull in rough water. The problem with high deadrise is it causes small boats to lean into the wind when under way or when loads shift. You constantly mess with trim tabs. That is the trade off for a soft ride. Once you get into medium sized boats of 35 to 40 feet, fine entry with a modified vee becomes comfortable and is generally pretty stable. You see some pretty good sized boats that don't have a great deal of deadrise but are very comfortable due to entry, length and weight. Some of the Hatts fit this description.

 

[wickeral]

Hey Guys! Don't forget the Chines and their relationship to a boats Stability. Soft Chines are Rockers and Hard Chines are Stable. Granted this factor is more prevalent at Rest. Al W.