View Full Version : 39 foot sharpie houseboat

Mark Van
11-22-2000, 03:36 PM
I'm currently building a 39 foot sharpie houseboat of my own design. (I call it a "houseboat" for lack of a better term. This is NOT an RV looking thing.)
If anybody is interested in seeing it, I have lots of pictures on my web site http://markvdesigns.com

11-22-2000, 04:30 PM
The plan looks good to me, fun.

Steve Souther
11-24-2000, 07:31 PM

Great project! Looks like you've got a boat that will survive a hurricane (2" bottom)! And, the photos are up to the minute, too. Can't wait to see it floating and hear all about the first sea-trial.

Fair winds,


Alan D. Hyde
11-27-2000, 11:04 AM
Is the cutout for the outboard as deep as it looks on the three-D image?

If so, I would consider an outboard well of some type to provide adequate freeboard astern.


Tom Lathrop
11-27-2000, 03:57 PM

Your power sharpie looks like it will give you the room and mobility that you seek. At first glance, it looks a lot like Bolger's Tennessee-Idaho-Wyoming series, but you have gone pretty far from them in size and displacement.

According to one owner of a Tennessee, the flat bottom does indeed pound into a chop. In fact he reported that it was downright uncomfortable when driven into a chop. It will also be very noisy at anchor unless the chines are kept submerged.

I had experience with one powerboat with a flat bottom aft and chines that were parallel. It had very poor directional stability and steering was uncertain. Your CB will undoubtedly help, but I would like to have the chines narrow at the sterm to about 85% of max WL beam and put in as much skeg as can be fitted without hurting your draft requirement.

Some builders of the Tennessee have ignored Bolger's warnings and added too much weight up high and created a possibly dangerous situation. I assume that your heavy hull construction is intended to eliminate this problem.

I'm sure that Heart Of Gold was harder to build, but the hull looks more easily driven and quieter. I doubt that 40HP will drive the boat much faster than the a 25 but it may give some reserve if you need it. The boat will surely not plane anyway.

Looks like a great project you have launched. The small 20 footer looks great too. Frank Hagen ought to take a look at it since he is interested in something about this size.

Mark Van
11-27-2000, 05:29 PM
The cutout for the outboard on both boats is the proper hight for a 20" shaft outboard. The 20 footer has a full hight bulkhead between the motor and the cockpit, and the 39 footer has a self-bailing cockpit.
As to the pounding in a chop. This is primarily a liveaboard, and I don't plan on taking it out in bad conditions if I can help it. Also, since I will be sleeping aft, I don't think I will be too bothered by the pounding at anchor.
The Heart of Gold had a canoe-type hull, and it was extremely unpleasant going into a headsea. It pounded something awfull, and threw an enormous amount of spray. It also rolled extremely violently when encountering the average small powerboat wake. I think the hard chines will reduce the roll.(not to mention 2' wider on the bottom and about 3 times the weight)
The Heart of Gold was extremily efficiant. I usually cruised at about half-throttle, which gave me 6 knots, about what I predicted.
I used charts in Dave Gerr's Propeller Handbook, and figured that it would take 30 HP to push the 39 footer at 10 knots, which is as fast as I will want to go.
I did have a ride in a Bolger Sneakeasy, and I was impressed at its stability and lack of rolling in a beam sea.
Basicaly, I wanted a boat as simple as a Bolger box, but as nice looking as a Benford fantail cruiser. I will end up with something in between.

Tom Lathrop
11-28-2000, 10:12 AM

I am also sold on hard chines for stability on a powerboat. You can get some rather quick snap movement in some wave conditions but over all, I find the hard chine more comfortable and, as you found out, much drier underway. I will be very interested to see your HP/RPM/speed curves when you get it on the water.

As for the noise at anchor, my own boat is a 10 degree deadrise monohedron with 25 degrees at station 2 1/2. I thought the it would be quiet at anchor but failed to take the chine flats into account. The ripples funnel into the apex of the bottom/chine flat angle and slap when anchored in a breezy spot. Unfortunately, this is right below the bunks but it has not kept me from sleeping so far.

Mark Van
01-07-2001, 05:05 PM
I've just finished puting the cabin roof and sides on. I am very pleased with the way it looks.
In reply to the earlier comment by Tom Lathrop about the derectional stability. I think that the reason sharpies have bad derectional stability in a following sea has a lot more to do with the bow shape than the stern shape. I don't see how having the chines parallel aft would make any difference. I put a large radius on the chines forward, to cut down on turbulance.
We'll all know more about it in another year.