Please Review Hull Form

Hello Everyone,

I am hoping that the forum can provide commentary on some hull lines that I am working through.

A little bit about the concept: An economical powerboat to operate on a semi-planing hull in partially protected waters with specs as follows:

LOA: 32.5'
BOA: 8'-6"
Draft: Approx. 1'
Displacement: 7,200 lbs (typically loaded)
Desired Cruising Speed: 12-15 knots
Desired Max Speed: 20 knots
Hull Construction: Aluminum

This warped hull form is partially based on the NTUA series (in paticular the double-chine aft).

Please provide some general commentary/an informal peer review. Any feedback is appreciated!

Thanks.

 

It's an ancient design. You can get plans that are proven to work well for very cheap from old designers; probably their estates. The cost of plans is one of the least when building a boat. That weird facet on the aft chine seems counterproductive. At semi-planing speeds you want a clean water exit. That looks more appropriate for low speeds. The deep forefoot will likely trip in following seas and make the boat broach. How are you getting a displacement before having weights from all the structure, machinery, interior, etc. ? Also, with a draft of 1' you would need a tunnel to accommodate the propeller and rudder, and it would only have space for a tiny one.

 

daydreamer - you mention aluminum construction. The shape does not appear to be developable with the hollow sections amidships.

The small distance between the chines aft may mean the differene from an equivalent single chine hull is negligable.

Another warped bottom series is described in The Naples warped hard chine hulls systematic series - ScienceDirect https://www.sciencedirect.com/science/article/pii/S0029801817302251 Offsets are near the end of the paper.

 

all good observations & advice.
You have what some call a 'double wedge' hull form. (see sketch)
Deep forefoot/shallow stern + fine bow/broad stern = broaching hull form.
I have had the (dis) pleasure of operating a few of these creatures and they are trouble. And, your 'hollow' flare bottom will only contribute to the problem.