GT 23 hull questions

[jbo_c]

As seen on another thread, I’m considering taking over an incomplete GT23 project. That hull is not really what I was looking for originally, but it is tempting. So I have a few questions - mostly for Jacques, I guess.

1. The “houseboat” hull: According to the study plans, the difference is in the forward volume and the transoms are the same. So the houseboat hull is also what we’d refer to as a “planing hull”? Or maybe as a whole, the design is more semi-planing?

2. Along those same lines, Jacques notes that a 25hp would be perfect. That still confuses me if the hull is a planing hull. How is that? Is this statement true for both versions of the hull?

3. This one may be harder to answer. My intent was to have the cabin more aft. Since this is the ‘performance’ hull, I’m thinking my aft cabin would actually be the better way to do it anyway. Is that right? How do I make sure the weight distribution is “correct”? Looks like my I intended cabin will be lighter(smaller) than what’s on the plans, but probably not a lot as I really don’t have any plans to make it out of foam.

One of my biggest ‘concerns’ is that my intent has always been for very low power - 10hp or less. Don’t want to invest a lot of time and money in this only to wish I’d stuck with my original thoughts. (I know I’m the only one that can make that call.

Jbo

[Dougster]

As I recall the planing hull was trimmed too low in the bow for some builder or builders. That's a pita as rain won't drain out the stern, etc. The displacement hull, with more volume forward won't have that tendency, and for low power seems like the one of choice for sure. It's the one I'd go with fwiw.

Dougster

[jbo_c]

I remember it like you Dougster, though I can’t find the posts. I had thought maybe I could find what others have done for remedy.

But the thing here is that I don’t have a choice, the hull is already assembled.

Jbo

[Dougster]

Then it's a matter of trim and moving weight toward the stern of course, which you are considering now. Nothing beats getting the hull in the water though.

Dougster

[Jaysen]

Was it the frame sole hight or an actual change in the hull shape?

If the former it shouldn’t be difficult to raise the sole supports back to the desired location.

[jbo_c]

Not sure I understand the question, Jaysen.

Jbo

[Jaysen]

I was kind of poking at this statement.

As I recall the planing hull was trimmed too low in the bow for some builder or builders. That's a pita as rain won't drain out the stern, etc.

If the drainage problem is created by the sole (floor) being in the wrong position, it is possible to change the sole height. I’m certain there is someone smarter than me that will provide more insight.

[TomW1]

jbo I think I would pass on this one. With the planing hull you will need the higher HP motor Jacques suggests. A planing boat always requires more HP to move it. As Jacques says the 25 is good for 6-10 mph. Not something you want I believe.

Tom

[BB Sig]

Was it the frame sole hight or an actual change in the hull shape?

If the former it shouldn’t be difficult to raise the sole supports back to the desired location.

It was a change in the hull shape. Moving the cabin aft should fix that. Raising the sole would not.

My plan was to keep the weight as far back as I could. With a folding bow transom, the bow becomes your entry point. With minimal framing in the front and the use of beanbag chairs and and aft cabin, I think it would work but get Jacques input!!!

[TomW1]

If you want to move the cabin back definitely get Jacques input. As this the planing hull it is more sensitive to weight changes You will probably need to add weight forward. Maybe something like lead ballast.