Range of Stability for Early IOR boat

After reading your Offshore Cruising Encyclopedia I have a couple of questions about converting an alum. IOR boat to a cruiser. The boat, Doug Peterson 44′ alum. flush deck, displ 25,000 keel 10,000 , 13’6″ beam 8′ draft. Built 1978. Intended uses of boat, Mexico and South Pacific.

Should I be concerned about the range of stability? If I buy this boat I plan on adding extra tankage low in the hull and under the floorboards if possible.

Is there a formula to figure range of stability ?

And lastly, I really like the 14′ Wherry pulling dingy. Are they still in production?


Hi Gene: Range of stability is a tough one to rough out. You really have only two choices to do it right; go to Doug Peterson and see if he has the data; or two, get an IMS handicap measurement which will work it out for you.

In general, early IOR boats tended to be conservative in this regard, but it is always better to get the real numbers.

Re: new tankage, the odds are your vertical center of gravity is several inches below the floating waterline, so you will need the fuel low down in the bilge’s to make it help VCG! Re: Wherries, I am not aware of anyone building these today.

Good luck with your project. Steve Dashew

Posted by Steve Dashew  (November 30, 1999)

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