Bulbous bow available in many shapes and sizes, generally the bulb looks like a section of large diameter pipe with a domed end sticking out of the bow of the boat, underwater. Side bulbs, bilge bulbs, and even stern bulbs have been tried but the most consistent results have been achieved with bow bulbs. Today, to see a large ship without a bulbous bow is a rare sight indeed. Their results have been proven over countless thousands of deep ocean miles in all kinds of weather by all kinds of vessels.
So what's in it for you?
The benefit of a modern day bulbous bow will reduce your fuel consumption 12% to 15% giving you the equivalent greater range, or a slightly higher speed for the same power applied, whichever you choose to use. The greatest amount of benefit will be at the high end of the semi-displacement speed range, reducing as your speed decreases. At higher speeds wave making resistance accounts for the greater portion of the drag, and the slower you go proportionally more of the resistance is taken up by wetted surface drag. At low speed (around 6 knots and lower) the bulb will even cause an increase in drag because of it's greater wetted surface area. Luckily at that low speed the added power consumption is negligible and generally little time is spent in this speed range.
In addition, you will find increased sea keeping ability due to dampening of the pitching motion. When charging into head seas there is the chance of slamming the bulb on the troughs, but this is limited to a very narrow range of wave train and heading. A slight change in direction and/or speed will cure this ill-effect.
How does it work?
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