Deadrise Degree: 21 vs 19 = best performance?

guizmo

Recruit
Joined
Feb 22, 2006
Messages
3
Hello,<br />I'm currently shopping to purchase a new boat (first boat) and I'm comparing two: both 2006, 17'6" with the MERC 3.0 (135hp). <br /><br />1) Maxum 1800MX; weight 2000lbs; deadrise degree at 19.<br /><br />2) Larson SEI 180 Sport; weight 2300lbs; deadrise degree at 21.<br /><br />Now, even though the Larson is heavier by 300lbs I'm told by the dealer that it would best perform due to bigger deadrise degree which will help plane faster and would actually be easier on gas. The way I see it, 300lbs is like having two extra people at all times in the boat? <br /><br />This is assuming we're doing the same activity with both boats.<br /><br />Any advice to help my purchase is greatly appreciated.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Deadrise Degree: 21 vs 19 = best performance?

Welcome to iboats. :) <br /><br />Flatter bottom boats plane quicker, ride bumpier. 2 degrees ain't much difference. The two are such a dead-heat, the numbers will be awfully close. Savings in gas over the lifetime of one boat over the other would be in the hundred dollar range (if that). Pick the purtiest or the cheapest. The Larson may hold trade-in value better. But it's all such a toss-up ... aw heck! Let the wife choose. THAT ould make a huge difference. Everything else is puny in comparison if it makes the wife happy! You'll be trading it for a boat with a 4.3 in a few years either way. ;) <br /><br />By the way, lower numbers are flatter. The salesman has it backwards. The 19 dgegree is flatter and should plane faster and use less gas. 300# lighter would boost that as well. Beam and length also play important roles in how a hull performs. But you'll never really know unless you run the two side by side with identical motors and loads.
 

KRS

Banned
Joined
May 15, 2004
Messages
2,383
Re: Deadrise Degree: 21 vs 19 = best performance?

Look at the other features, the 2 degree difference is not enough to matter.<br /><br />Whichever one you like more, don't let the 2 deg make the choice.
 

guizmo

Recruit
Joined
Feb 22, 2006
Messages
3
Re: Deadrise Degree: 21 vs 19 = best performance?

Thank you guys for your input. <br /><br />Since I shouldn't sweat it on the 2 degrees difference...would 300lbs difference between the two make a singnificant difference in performance? <br /><br />As I mentioned before, the way I see it is, 300lbs more is like having an extra two people on board...<br /><br />Thanks again!
 

KCook

Lieutenant Commander
Joined
Jan 24, 2002
Messages
1,624
Re: Deadrise Degree: 21 vs 19 = best performance?

The other guys got it right about higher deadrise resulting in slower performance numbers. What the Larson salesman "forgot" to tell you about that Larson is that it also has wider chines than the Maxum. And wider chines result in a harder ride. Does this exactly cancel out any benefit of the greater deadrise? Could be. The only way to know for sure is to get demos in both boats. My bet would be that there is not much difference at all. Here is another thread that may help -<br /><br /> Sampling entry level bowriders (18') <br /><br />Kelly Cook
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,778
Re: Deadrise Degree: 21 vs 19 = best performance?

Deadrise doesn't have squat to do with mpg or mph. It affects your punishment level.....i.e. how she dives into waves and sheds them. Your (aft) hull shape has more to do with speed, comfort, and mpg.<br /><br />A padded or stepped deep v hull will lift out of the water (once you get it going), thus reducing hull drag which, outside of the lower unit drag, is your #1 enemy. Guarantee you that 300# on the wrong hull will evaporate and then some on the right hull. A flat bottom will put you on top fastest, but once there the other two will run circles around it. BTDT.<br /><br />Remember; the less the wetted area, the less the friction, the less hp required for a given mph, which translated to more mpg.<br /><br />So, like the guys say. Run em and then decide.<br /><br />Mark
 

KCook

Lieutenant Commander
Joined
Jan 24, 2002
Messages
1,624
Re: Deadrise Degree: 21 vs 19 = best performance?

It would be neat if keel pads were common on I/O bowriders. For the reasons Mark cited. But they are really very rare on I/O bowriders. Pretty common on bass boats though. And many tournament ski boats are so flat bottomed you may as well say they have a pad.<br /><br />Kelly
 
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