Show us your bottom

I’ll stick my neck out with some comments .

Interesting how many boats have adopted the deltaconic idea. Other than the depth of the Vee the Hatteras and Carver hulls are remarkably similar. Deepish forefoot for wave braking Vee and keel for stability flat "chine shelves" for speed and roll resistance.

Notice the curved shape of rudhons Crirs. Probably for smooth ride at the expense of pure speed and roll resistance.

I don’t see anything in Flywrights hull to make me say semi displacement. Given enough power that is a planning hull with all those straight runs aft and flat sections IMO though it may be operated and powered to be no faster than semi displacement mode.

Poco’s hull has many true trawler aspects.The only one shown so far Full sections forward and hull rises toward stern to reduce drag but doesent quite make it to avoid a square transom and reduce drag.

Old salts boat was designed for lift and speed.

Andys boat says speed. Immersed hull seems narrow for the overall beam but that might just be perspective of the PIX. Prop pockets add efficiency while reducing slow speed maneuverability and increasing wake at other than fast cruise. And a smallish keel for improved tracking.

Many hulls are designed to run on a narrower surface when on plane for speed but immersed wider beam at rest for added roll resistance and increased slow speed lift to help get up on plane. I put delta conic and possibly Andy’s in those categories.

Nwaring’s mainship looks to have rounded chines. If so that reduces roll resistance but also reduces drag. Not much lift to plane.

How am I doing??
 
I guess I never really looked but the Carver 370 Hull is very similar to the 440 Hull. A lot different than the 355 or other models.

Those Trojan international hulls are amazing in rough water. I ran a 12 Meter Motoryacht back from a boat show this year in 6-7 foot close together Lake Michigan waves and the boat never once pounded and we maintained 18 knots the whole way back (about 12 miles).
 
Bruce...you are correct, a beam sea is not fun. Getting on plane takes about as long as it takes to push the throttles ahead.
Niles
 
Too much? :D I dunno because we never stay there long enough to get a handle on it. I will run her WOT once in a while to blow things out. Usually at the end of the day. But we probably burned 75 gallons running about three hours up the Hudson once at around 17K/2100 with a light load. WOT = 2300. With a relatively heavy load she will break 19k at WOT. But the keel acts like a water ski and she chine walks above 16 or so.
 
quote:
Originally posted by pdecat

I’ll stick my neck out with some comments .
....
Andys boat says speed. Immersed hull seems narrow for the overall beam but that might just be perspective of the PIX. Prop pockets add efficiency while reducing slow speed maneuverability and increasing wake at other than fast cruise. And a smallish keel for improved tracking.

Many hulls are designed to run on a narrower surface when on plane for speed but immersed wider beam at rest for added roll resistance and increased slow speed lift to help get up on plane. I put delta conic and possibly Andy’s in those categories.

How am I doing??

Click to expand...
Not bad at all!

It's a Fat boy sitting at rest-very stable.

I'm sure the prop pockets should have an effect on slow speed maneuverability, but with the big wheels and torque I don't notice. Matter of fact if I don't use slow vessel mode and keep it at normal idle speed the rear squats when I put it in gear

Once it pops out of the water with Turbos spooled it feels that speed increases geometrically but looking at my numbers it's downright right linear from 1200RPM to 2200RPM - picking up 1Knot for each 50RPM

And it seems the small keel does help the boat track very well at all speeds
 
"Old salts boat was designed for lift and speed.
...
How am I doing??"

You got that right, Bruce!

Easy to get on the plane and keep it there.

A couple of interesting experiences. Low tide in the Strait of Georgia, and we are headed up the Fraser River, against the spring run-off, on the plane, at 8 knots SOG. The river was doing the rest.

In the Gulf of Alaska, headed South from Pelican to Sitka, against some pretty big swells. Planing at 11-13 knots on the upside of the swell, and backing off on the throttles to coast downhill at 15-17 knots.

Nice practical, livable interior, too. The 12' beam adds a lot of room inside.

OS
 
This is an interesting thread. Why do prop pocket increase wake?
 
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tunnel7.jpg
 
quote:
Originally posted by mx8

This is an interesting thread. Why do prop pocket increase wake?

Click to expand...
Alan
This is the short version- When the props start rotating they will start sucking water through the pockets and creates a vacuum which in turn sucks the stern down into the water. this will increase the wake but the stern jumps up on plane much quicker

You can get more detail with a paper from Don Blount "Design of Propeller Tunnels for High-Speed Craft"
 
quote:
Originally posted by abalmuth

quote:
Originally posted by mx8

This is an interesting thread. Why do prop pocket increase wake?

Click to expand...
Alan
This is the short version- When the props start rotating they will start sucking water through the pockets and creates a vacuum which in turn sucks the stern down into the water. this will increase the wake but the stern jumps up on plane much quicker

You can get more detail with a paper from Don Blount "Design of Propeller Tunnels for High-Speed Craft"

Click to expand...

That`s enough detail for me, Thanks, I`ll need to add a note to my "No Wake, Please" sign, "Boats with deep prop pockets, please speed up" :)
 
That was designed for a comfortable ride while still being exciting when it gets going.
 
In addition to what Andy said IMO the pockets reduce lift area and boyancy aft, sort of the opposite of wedges and trim tabs. They tend to squat and in that mode produce prodigious wakes. Andy: not much forefoot, does it pound in rough weather?
 
Wow! you guys have some clean boats! I couldn't help but notice how clean your running gear was. I have mine cleaned every month, and I clean it myself quite often when I'm in clean water. I usually use a small scraper and a steel brush. I do a lot of diving, so getting under the boat is not a problem. Are you guys using something else to clean the running gear? Sand Paper, emory paper?
 
quote:

That`s enough detail for me, Thanks, I`ll need to add a note to my "No Wake, Please" sign, "Boats with deep prop pockets, please speed up" :)

Click to expand...


Thats why I always laugh when I see people pull the throttles back in some situations to prevent a wake... at some point, it becomes too late and staying on a plane creates less of a wake then letting the stern sink in 4 feet underwater and throwing a whale tale.
 
quote:
Originally posted by pdecat

In addition to what Andy said IMO the pockets reduce lift area and boyancy aft, sort of the opposite of wedges and trim tabs. They tend to squat and in that mode produce prodigious wakes. Andy: not much forefoot, does it pound in rough weather?

Click to expand...

Bruce
Actually It's pretty good, the problem is my boat just before this one was the Formula 41PC w/ 450C's and it was a tank so I use that as a basis of comparison.

This past labor day weekend we were in some 4-5+ footers running to Jersey city and I slowed down to 17-18 knots and I did not spill the coffee.

I'm getting/feeling old and if it get above 5-6 footers - no problem for the boat or me but I'd rather hang out till it passes
 
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