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Old 03-13-2019, 12:28 AM   #5
makobuilders
Guru
 
City: Canaveral
Country: USA
Join Date: Jun 2012
Posts: 1,534
Good articles above.

I doubt the cost of retrofitting a small boat would ever be recaptured. However for a new construction it would be different. Two shipyards that I have been discussing with have bulbs in their designs. In one case the boat is very front-heavy and the added buoyancy is a benefit and pitching is slightly reduced. In both cases the waterline length is extended about 4-5 feet, so LWL is almost the same as LOA. The naval architect told me he estimates about 5% efficiency increase, which coincides with the longer LWL.

Regarding to negative motion, articles indicate bulbs can act like a deep forefoot, and when running downwind in heavy seas there may be a slight tendency to drag, but how significant this risk is to you is debatable.

In general T.G. I would say that if the 40-60 ft boat you're buying comes with a bulb, then great. And if it doesn't, then great. But if you want to learn more from actual naval architects, and some experts, then head on over to boatdesign.net/forums

Oh BTW you need to be careful about anchor roller/hawsepipe placement.
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