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I intend to build a wooden Sweet 16, but like to study and plan before undertaking such a project. I have the Plwood Building Book, Inboard Motor Instal Book, Study Plans, and this great forum.

I intend to stretch the Tug 10%.

The study plans recommend max speed, hp, and motor weight: 5.5, 20, 250.

With the 10%, How much can I safetly increase these numbers? I'd like to cruise at 10 kts, but not sure if this hull will permit this.

If I fabricate a fiberglass shaft log, can I extend it into the bige and attach my stuffing box to the glass log ? (as opposed to a cast bronze log) The glass log would be epoxied to the keel and bilge.

Does anyone have the full plans for this ?

Thanks in advance for your replies.

Doug,

For a displacement hull, like the Sweet 16, the maximum speed is equal to the square root of the waterline length x about 1.34. So, this hull as a LOA of 17'2". For estimates sake I would say the LWL might be around 16' (just guessing, given the plumb bow and the short overhanging transom). So, this gives a speed of 5.36 knots (sqrt. of 16 (or 4) * 1.34.)

So the disclosed speed of 5.5 knots seems accurate (trust the designer). That is truly the maximum hull speed. You will not be able to get a true displacement hull boat to cruise at 10 knots without having a waterline length of of around 60' (sqrt of 60 * 1.34). I am not a naval architect, but I know it has something to do with the boat not getting on plane because it can't get over its own bow wave. Additioanally, on a displacement hull boat, increasing horsepower will only do one thing....burn more fuel for minimal increases in speed.

I hope this information is helpful. But the designer's specs are pretty much right on for theoretical hull speed.

Robert

There is a fiberglass tube glassed into the hull on my 38'sailboat just as you described.A short length of hose is then clamped to the tube &to a bronze stuffing box with shaft packing seals in it.Works just fine,but you need to have the tube aligned pretty close,or there would be stress on the rubber hose taking up the alignment

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