Blueprint Until You Are Blue in the Face
Blueprinting has been written about since the beginning of time or at least since the beginning of trying to make boats go faster. This is a quick overview of what to look for and a few tips. I have experienced the benefits first hand from removing minor hooks to literally just cleaning up minor imperfections. Additionally, I have referenced articles by Jim Russell from Aeromarine for specific details. Jim Russell is an engineer and performance hull design expert who has decades of experience. Why blueprint? It will absolutely make your boat faster and more efficient. Who doesn’t want to go faster and save money on fuel?
First off, every boat can be a candidate for hull blueprinting. The most critical portion is the wetted area of the hull while you are underway and experiencing some lift, typically the last 3 feet of the hull on a small performance boat. Looking at the whole hull is important though for a few reasons. If you have an older boat, you want to make sure your hull has integrity. Time, rot and fatigue might show up as warps in your hull.
Our old 22 Donzi Classic would be left in the water briefly, even just a little dirt would slow it down. Don't use bottom paint on a performance hull and clean your hull often.
Once you have established your hull is solid, go ahead and clean your hull meticulously. You may have to use cleaner and scrub rigorously. Inspect and mark the hull for any nicks, gouges and scratches. All imperfections can negatively affect your performance. Second, use a long straight edge to determine if your running surface is true. Run a straight line down the keel and use your straight edge across your hull with your centerline as a reference. If you see a gap or light under part of your straight edge, you have a hook in your hull. If you notice your straight edge can’t lay flat, you may have a rocker to your hull.
After you have marked your dings, gouges and scratches to be fixed and determined whether your hull is straight or not, go ahead and repair the imperfections. Depending on if you are dealing with the original gelcoat or paint, use the appropriate materials. Once the dings are fixed and if your hull isn’t straight, you want to fill to remove any hook or rocker. You will have to fare it out and spend quite a bit of time to do it right.
This 16 Norwester jet, with a 380 HP, 460 Ford, had a moderate hook removed, blueprinted and went from 67 to 75 mph.
Next is to sharpen all edges and make sure they are perfect too. This means chines, strake edges and any line or angle on the hull.
This takes time and effort but it actually saves you so much in the end. Here is why. If your hull is hooked and or has imperfections affecting performance, you lose efficiency dramatically. If you are trying to go faster by adding power, you will waste all your money on tuning your engine or upgrading it if your hull isn’t 100%. Even a dirty hull, with minor algae or grime can lose 3 or 4 MPH. The fuel savings alone would be worth it.
Blueprinting your hull is critical to performance, top speed and handling. Hulls with rocker won’t stop porpoising, hulls with hooks can dive into turns and no matter how much you trim will never lift. Top boat manufacturers make sure their hulls leave the factory at their best but surprisingly, many hulls are not perfect even when new. Older hulls can benefit greatly from blueprinting. When it comes to special waxes or speed coatings, don't bother, just make sure your hull is clean and smooth.
Before you spend money on your engine to gain speed, look at your hull. It is the key to how your boat performs.
Great source for technical articles and research.