Michalak Jon20 as a platform for a motor cruiser

This might show the stern a little more clearly.

 

Yes, weight aft will be some small concern. Haven't done firm calculations, but thinking maybe if I do cabin structure with 1/4" and foreword structure with 3/4", it will come close to balance. Will also have two batteries, so I can experiment with their location for balance as well.

Thanks for bringing up good points to consider.

Jbo

 

Also, under way, all crew weight will be forward of center, so I think primary concern with trim will be at rest at night when "ballast" can be moved to best suit comfortable trim for sleeping.

Does that sound like reasonable logic?

Jbo

 

Seems like you have considered the weight distribution issues.

 

Four years later, but I’ve actually started building this boat now. Glassing the hull bottom tomorrow if all goes well. Hope to flip and get inside of the hull glassed before cold stops work for the year.

Some changes made over the years between, but the spirit is still the same. Will look(and be) much inspired by Atkin’s Retreat. Hull will still be Michalak’s Jon20, but stretched to 22’.

Jbo

 

See if I remember how to post a pic.

 

Laying out glass.

 

Much worse job of glassing than I thought, but done wet on wet. Now lots of fairing and sanding. Probably have to wait for spring weather at this point, though.

 

Looks like you kept the aft run as specified?

I was going to recommend that, as it will support higher speeds and less sensitive to stern loading at the cost of just a little efficiency. And you'd get most of that efficiency back by moving weight forward which will happen anyways with your layout.
If you did want aft rocker for efficiency it should be less than the front. 3 to 6 inches would be great.

 

Yes. I finally decided to maintain the straight run aft. Several factors in that decision. Not least of which was that if I decide to run, say, a 9.9 high thrust on it, the difference in fuel consumption would be negligible anyway.

On the other hand, if I just hung my old 18hp Fastwin on it for a little more power, it has about the same fuel consumption at all throttle positions anyway.

Also, with my arrangement, more buoyancy aft can only help.

Jbo