Bowrider hull

Hello, I am a student of naval arhitecture and I d like to ask you a few questions regarding hull design. I was given an assigment of designing a bowrider hull approximately 1o m/30 ft in lenght with a max speed of again approximately 45 knots with (sterndrive). Since I have never designed a bowrider hull, any hull for that matter, I d like to ask a few questions. How much I understod its a V hull shape with a 21-22 degrees deadrise, and bowriders are mostly specific for their deck design, so a V hull of any speedboat would be appropriate? I haven t been able to find any examples of hull lines online so any would be appreciated. Also, I can find my way in Rhino so if I were to design it from scratch what would be the starting point, any literature recommendations? Any help is appreciated

 

Welcome to the Forum Ivan.

There is a Cobalt 336 here in Barbados (i have had survey jobs on it in the past), and one of these boats sounds like it might meet most of the requirements for your assignment.
Here are 6 typical sisterships for sale -
Cobalt 336 boats for sale - YachtWorld https://www.yachtworld.com/boats-for-sale/make-cobalt/model-336/

 

A bowrider is defined by the deck configuration, not the hull. It can be a V-bottom, tri-hull or catamaran. At 10m length it is not too critical to have a full wide bow though, so it may be possible to use a design with finer entry.

 

Thank you I will use them as a reference.

 

Thank you, I tought because of the deck maybe the hull needs to be different somehow. I found some V hull speedboat lines so I will use those, thank you

 

Bowrider configuration seldom appears to be a well considered or engineered feature.
Bow (over)loading is far too easy to accomplish, and can result in disaster.
I think it appeals to the inexperienced buyer who pictures it stuffed with bikinis and flying across the waves.

 

The numerous videos on YouTube showing every type of boat (including bow riders) going in and out of Haulover Inlet in Florida illustrate this very nicely
Here is just one example. Bikinis being tossed out of bow riders seems to be a common occurance there.

 

I've read kapnD's comment and had exactly the same thought as bajansailor. I love those videos

 

Since it's an assignment from school I guess a V-hull may be required? The angle of deadrise depends on the intend of the boat. You could say a smaller deadrise decreases resistance and planing will benefit from it, while a bigger deadrise hull will cut more smoothly through rough water but there is probably much more involved for choosing a good deadrise. Maybe there are other people here who have a better understanding regarding deadrise.

For Rhino I would start with drawing a few 2D views.

 

For this particular size and speed 21 and 22 degrees is mostly used so I will run with that.

 

Bajan, I have always thought that bow riders were (are) an accident waiting to happen, since they were first introduced. They are just a clever, and not very safe way to cram more occupant space into a small boat. Now it's even worse because the design is being used in bigger and bigger boats. Prime example, the 30 foot boat the OP is assigned to design.
Haulover is a fine example of what people should not be doing in bow riders (and you even see pontoon boats trying to navigate the channel). The only place for bowriders is calm water.

 

@Ike you summed it up perfectly with your post above!

 

Thanks. Did you notice that the boat that had the least trouble navigating the inlet was the old 40/s/50s era cabin cruiser? Not fast, but stable and nowhere to take a lot of water on board. Fully enclosed cabin.

In the spirit of full disclosure, my boat is a 1972 Sea Ray, closed fore deck. I don't like bow riders.

 

It’s common for work/fish boats to be designed to carry weight and work off the bow, the working equivalent of a bowrider , but the needed stability is designed in, often with a high bow and robust underwater profiles.
The sport boat industry takes no such measures.

 

I would go higher deadrise……maybe 24deg