Rebuild my Sportcraft in Aluminum...

[CKP]

I currently own a 23 foot Sportcraft with a 18 degree deadrise.

I like everything about this boat except the deadrise when I run offshore.


Since I own the pink slip on this boat I wanted to replicate the design in aluminum but change the deadrise from 18 to 24 degrees.

Your thoughts on trouble areas that I will encounter?

Regards,

CKP

[Eric Sponberg]

Well, assuming that the boat is going to be roughly the same weight, it will float somewhat higher in the water because of the increased depth and volume of displacement. If the boat is powered by an outboard motor, then the height of the engine and bracket where the motor mounts will be important for the depth of the propeller. If the boat is an inboard or I/O, then the engine will likely sit deeper in the hull accordingly, which is not a bad thing. However, it is desirable to have the chines slightly submerged when the boat is at rest, and if they are at or only a little below the waterline now, they could rise above the waterline in the new design. So proceed accordingly making sure that the boat won't sit too high in the water.

Be careful of too much curvature in the bottom hull panels forward, and too deep a forefoot, both of which could lead to steering problems. With the higher deadrise but for the same overall weight, you will notice that the boat will take a little more effort to get up on plane and overall it will not be as fast. The new boat may need a bit more horsepower because of the increase in deadrise. A bigger engine will be heavier, and that helps keeping the boat lower in the water.

Those are a few of the basics.

Eric

[CKP]

Eric,

I just joined yesterday and was amazed at the projects on this site.

I want a Contender/Yellowfin bottom deep vee design.

In Texas, our waves are short 2-3 footers with periods of 4-5 seconds.


CKP

[Eric Sponberg]

I am not that familiar with specific sportfishing designs enough to recommend one over another. I recommend you go with the style of boat that is common to your area--the fishermen know what is best, as you have probably surmised. If Contender and Yellowfin are common and well-liked, then there you are, that's your model.

Eric