Help me find perfect hull for my Goals, motor?

I need help; any one with knowledge or similar experience of how to accomplish these goals and stay within my parameters would be greatly appreciated. My goals are a boat that can cruise at 10-12 MPH, ride well if water is choppy (stay dry in small waves) and seat 4 comfortably. To use my trailer I cant go over 16' in length or 6' 6" in beam and 1,200 pounds. I already have a 10HP Honda 4 stroke (short shaft, tiller) I want to use. It is currently mounted to a 14' johnboat which gives me more speed than I need (22 MPH), but a terrible ride quality. I would consider building/buying/modifying a boat or its controls to meet these specs. I am wide open on ideas. Thanks in advance for the help.

 

Strangely enough I am working with someone that has very similar needs. She came to me with an idea and a bit of experience with a modified RIB (she did the mod herself).

Below is a picture of what we have so far...

15'4" LOA
6'1" Beam
9" Draft @ 1680 lbs
Hull wt (Bare) should come in at about 400-500 lbs.
The use of the Box Keel should significantly soften pounding and increase efficiency at displacement and semi-displacement speeds (it did with her RIB). The lower chine has decent flare to increase heeled stability and help keep the boat drier The additional upper panel raises the freeboard and the chine helps stiffen the sides

Steve

PS. I'm not selling anything...I do it for the fun of designing and the hope of seeing it on the water...at least for the forseeable future.

 

Thanks for the info and help Steve; Do you think this boat would be able to plane or do you think I could displace the water at that speed? I have found a European website for outboard testing by Yamaha. They have some specs for a boat that looks like a perfect match by the picture and test results. Have you seen anything like this in the US for sale or design to copy? Thanks.

 

you would be planing and would probably run...14 mph or so with a 10 horse. I built a lightweight (100 lbs or so) stitch and glue motor skiff, which was clocked at 23 mph with a 9.5 hp Johnson. The problem with this is that the nose really lifts up and I have to shift my weight forward to get on plane faster. I believe with the box keel there would be a lessening of nose lift and a smoother transition to plane. Also, from a marketing aspect...I bet that that is the 20 on the back in that picture

Steve

 

Steve,

I really like your skiff. I have always been a fan of the box keel and a few years back I drew a skiff with a box keel (AKA displacement glider) that is similar with the idea of reducing the pounding but keep some of the advantages of the john boat. Please keep us updated.

Gary

 

No problem, happy to oblige and thanks for the nice words. I think this is pretty much final except for the angle of the box keel's bow... She doesn't like it as is, but likes it both raked to the same angle as the front transom and plumb. We'll sort this out in the latest flurry of emails. Too bad it usually takes 24 hours or so to do the go-around. She (Kristine) is from out your way...I think she said something about Northern Puget Sound in one of her early emails (I looked and am correct ). We actually started with a longer boat (below) but Kristine changed her mind and wanted to go with a shorter version.


Steve

 

Steve,
Did I say I really like this design! Hydro, if you load this baby so that the chine is just sitting on the water I think it will scream across the water with the 10hp. Steve I would like to know what the displacement is if the chine was submerged only .5 inches. I’ve played with similar lines and your lines are a winner. If the North Sounder builds, I would like to watch or even help.
Gary

 

Yup...but don't stop now !! Displacement with the chine submerged .5" is 1000 lbs (.457 tons) (Salt Water) (which might actually be a bit of a chore to get up to ). Of course it will probably have a bit of a nose up attitude with all that bouyancy forward unless the weight is carefully balanced. I'll pass along the offer, she might take you up on it.

Steve

 

I got the info back, she is on San Juan Island...which sounds like a bit of a trip. She likes the Idea tho.

Steve