Pilot 30 Dead Rise

Would anyone know the Dead Rise of a Mainship Pilot 30 ? Getting a transducer installed and would like to know in advance.

While I do not know....I am thinking damn near NONE!!! Might be a little but it is pretty damn flat back there

Mainship seems to prefer very flat bottoms aft. The older 34 Mainship is flat at the transom. Zero deadrise. A very warped bottom going from a very skinny forefoot w steep deadrise and a narrow chine beam to totally flat bottom is extreme warp. "warp" as pertaining to hull design .. not a negative expression.

The perfect monohull for steep head seas but not the best for following seas. Everything is a compromise and I'll bet the Pilot is not as extreme as the M34.

Nomad Willy said:

Mainship seems to prefer very flat bottoms aft. The older 34 Mainship is flat at the transom. Zero deadrise. A very warped bottom going from a very skinny forefoot w steep deadrise and a narrow chine beam to totally flat bottom is extreme warp. "warp" as pertaining to hull design .. not a negative expression.

The perfect monohull for steep head seas but not the best for following seas. Everything is a compromise and I'll bet the Pilot is not as extreme as the M34.

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We call that a semi planing hull.... The aft portion provides the lift to be able to exceed hull speed....the fore section has little lift and is able to go THROUGH the seas.

there are bubble level apps you can get for your phone.


put your phone where you want to mount the xducer and it will give you the degrees unless you picked a weird spot where the inside doesn't match the outside of the hull.

A good installer will have access to two piece shims that you can rotate through an infinite number of angles.

Baker said:

We call that a semi planing hull.... The aft portion provides the lift to be able to exceed hull speed....the fore section has little lift and is able to go THROUGH the seas.

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HAHA What's "semi" about them?
Full planing hull IMO.

Nomad Willy said:

HAHA What's "semi" about them?
Full planing hull IMO.

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Nope....you said it yourself..."very skinny forefoot w steep deadrise and a narrow chine beam"....there is no lift in the front half of the boat. A full planing hull will have lift up front. The Mainship does not....as you stated.

Mainship 34 Motor Cruiser

By Jack Hornor

Revised by BoatUS editors in October 2012


"The single engine, semi-displacement hull form with deep forefoot and a long deep keel actually more closely resembles Down East-style workboats and cruisers."

BoatUS - Boat Reviews - Mainship 34 Motor Cruiser

Baker and psneeld,
Opinions Opinions,
Bow decides nothing. Stern shape tells all.
Planing

However it's heavy (sort of) and is designed for slow speeds. It's a good 20 knot boat w enough power. I know you're not going to like this but consider the QBBL.
Not at all what a SD hull should have. In fact the QBBL is going in the wrong direction .. slightly. It's ideal for a planing hull. A good SD hull should have some positive number. And perhaps some rocker. The Mainship 34 is slightly negative. Negative QBBL bottoms are not the stuff of SD. It's a fact. But you could probably fine another twelve people to say it was/is a SD hull. Would'nt change a thing.

Lots of trawlers have a planing hull but are'nt considered planing because they have a keel larger than most planing craft. Island Gypsy is one. Zero degrees QBBL ... that's what most all planing hulls have. And for very good reasons. Calling the IG a planing hull is not really correct as it's designed for SD speeds. But the hull is a planing hull. Take the keel away and unload a lot of weight and you have a fairly typical planing hull w/o changing the hull at all. Same w the M34.

But you and most others call them SD hulls. Actually this could be resolved by calling them SD boats. If you leave the hull shape out of it, it's much more correct. Because the whole boat as a package is a SD boat. Has stuff (weight and keel) that are not found on planing hulls .. hulls.

So SD boats are fine (at least ok) but not SD hulls. But IMO if you have the stuff of SD on a hull (big keel and big weight) the hull shape should match .. it should have a SD shape .. and that includes a bit (or more) positive QBBL angle. Like the GB42 w 120hp. Powered for FD but the hull is SD. The GB42 single would be a better boat if it had a FD shaped hull aft. The problem w having it is that it limits a boat's speed. So if one were to repower w considerably more power the boat would squat at the higher speeds. Boats are'nt like cars where some are offered w a 4, 6 or 8cyl engine and all are legitimate. Boats are designed for a narrow range of speeds.

The bottom is not really flat. Sort of flat but not flat like a planning hull.
I had one and painted the bottom many times. LOL

Here's a picture of the bottom of my old 78 Mainship I. It's not the greatest angle to see the bottom but it's not really flat.


Actually the aft end of the bottom on my 40 Albin is much flatter (I would call it flat) than the Mainship.

Jay,
Would like better pics.
The one above looks like fast SD but one needs the whole picture.

The question is'nt about flatness but the angle of the bottom aft re a horizontal plane. The round bilge has little to do w it but the bottom rising up aft does. Nordic Tugs have a little rocker and thus have a small amount of positive QBBL. If the bottom ramps up to the surface (of the water) it's FD .. if it ramps up part of the way it's SD. If it ramps up not at all it's a straight line and a planing hull.

Uggghhhh. Eric, we have been here before. A Semi-PLANING hull has areas that do not produce lift. And who said anything about a keel. While a keel may cause issues with planing or speed, it has nothing to do with hull shape. It is something that is added for certain reasons. A common semi-"displacement" hull starts out with a very deep forefoot and slowly flattens out through the length of the hull. Flat enough to where if there is enough power, it will have enough lift to plane. A planing hull like a modified V will have enough "flat" sections forward to to create lift. I have owned and operated both. To be honest, most planing boats have MORE deadrise at the stern because they can afford it....deadrise softens the ride which is why manufacturers brag about it. THere is enough lift though the entire hull that they can leave VEE throughout the length of the boat to soften the ride. It does come at a performance penalty.


You know what the real test is Eric??? If you are on plane in a SD boat and turn, the boat will NOT bank into the turn. It will remain flat. A planing hull will bank. It is a slightly odd feeling and it looks strange as an outside observer. A Mainship will remain flat thru a turn. My Carver will not. I did look thru my old pics and the Mainship Pilot is not as flat as I thought...

Baker said:

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Damn Baker, Flyin Low had great lines. Even in the slings.

And the deadrise aft. I did not have a pic of the entire transom but you can see the deadrise. This is a Mainship Pilot II...the transition from no lift to the planing sections of the hull is more pronounced with the keel cut away. The first generation Pilot carried that keel all the way aft. Eric, if you were to argue that the Pilot II was closer to a planing hull than the first generation Pilot, I would agree. Mainship did a great job of capturing the benefits of a SD hull while also maximizing the benefits of a planing hull. This boat is almost two different hulls glued together where the keel is cutaway. The result is a faster more efficient hull with good seakeeping abilities.

CPseudonym said:

Damn Baker, Flyin Low had great lines. Even in the slings.

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I agree....I VERY good looking boat. ANd strangely, while the color of the gelcoat has nothing to do with the lines, it sure makes a big difference in the appearance department.

Carver modified V....you see hoe much lift is up front???

Baker said:

Uggghhhh.

You know what the real test is Eric??? If you are on plane in a SD boat and turn, the boat will NOT bank into the turn. It will remain flat. A planing hull will bank. It is a slightly odd feeling and it looks strange as an outside observer. A Mainship will remain flat thru a turn. My Carver will not. I did look thru my old pics and the Mainship Pilot is not as flat as I thought...

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Actually, it kind of funny feeling but the old Mainship leans OUT in a turn. It's kind of a freaky feeling the first couple of times.
So I used to do a hard turn to "rattle" any first time guests I had. Just for my fun of course.
:lol:

Jay wrote "leans out in a turn"

Wow, If a boat did that on sea trial I'd be say'in lets go back.

Baker,
Re #13 you're kinda stuck in aviation mode. I'm sitting here at Starbucks wondering if I want to talk about lift. I think not as this P v/s SD conversation has so little to do w it. Any boat has lift .. even my FD Willard. The bow rises at 7 knots and would do so w a planing, SD or FD hull. The stern pulling the aft end down w something like suction and pressure fwd caused by the mass of the hull being partly pushed up on the water that is reluctant to get out of the way. We can call it lift if you like.

The dynamics above pretain mostly to planing hulls. And rocker on the bottom (curved and convex) on FD and SD hulls suck or pull the bottom down so full planing speeds can't be achieved. Any boat w the transom out of the water at rest is in this catergory. And if the boat is emersed in the water the same aft (at the transon) as it is amidships it's a planing hull. It will have a straight run aft that prevents squating and hence allows planing.

Baker I can only guess at the hull form of the pilot. Never seen one out of the water nor have I seen good pics. But I have seen the older 34 and most of what I've said above pretains to that boat. There was a pretty red Pilot on my float about a year ago but all I remember is that it was pretty and the owner used the bow thruster a lot.

I agree w your post #16 and your coments mesh well w what I guessed about the hull. What part of the shape or what apendages promote you to say it's SD? I think it has roundish chines and some sort of a keel larger than most planing hulls have. Lobster boats have soft chines and significant keels. Most call them SD but I call them planing hulls. Again a straight run aft w zero degrees QBBL. Planing. Would plane better w hard chines and most or all of the keel removed. Lobster boats can go very fast .. over 30 knots I believe and on the right coast they race them .. 700hp and more.

But the old M34 is more of a planing hull than a lobster boat as it lacks the soft chine. Only the keel and big heavy diesel engine detract from it's being 100% planing. That brings me to another element of definition here that is most often overlooked. Grey area. There is no black and white. My Willard is definitely a FD boat. But there are features about it that make it more or less a FD hull compared to other boats. There are many boats that are more of a FD boat than my Willard. Some are trawlers. Many are sailboats.

But it remains that the shape of the stern mostly decides the dynamic hull type. No other feature tells more about it than the shape of the stern. A NT (a 32 at least) has enough rocker to put it firmly inbetween planing and displacement. A SD hull. So is an older GB.

From Soundings Magazine

A semiplaning hull such as this is supported by both buoyancy and dynamic lift.

Semiplaning
That brings us to this month’s topic, although the preamble was necessary to fully appreciate what the semiplaning hull can do. Any design, whether displacement or planing or in between, has capabilities and limitations. What’s helpful is to understand what they are so you can make an informed choice about which combination of compromises produces the boat that best meets your needs.
A semiplaning hull is simply one that operates in the gray region between displacement and full planing, a speed range at which the hull is supported partially by buoyancy and partially by dynamic lift. It is further made gray by the observation that a 40-foot hull at 20 knots is running at an S/L of more than 3, so it is, in fact, fully planing. But 20 knots is close to the top of its speed range, not the bottom, and that makes a very big difference in the boat’s performance, as we will see.
In the simplest terms, the semiplaning hull bears little resemblance to the displacement hull, but quite a lot of resemblance to the planing hull. As such, let’s compare the semiplaning hull with its full-planing counterpart.

Bilges and chines
For a semiplaning boat that routinely cruises between 12 and 16 knots, either a round bilge or hard chine hull will do the job. At 16 knots and higher, however, the hard chine is the way to go. That’s because hard chines start producing significant flow separation — deflecting water flow and spray away from the hull surface — at these higher speeds.

http://www.soundingsonline.com/boat-shop/on-powerboats/287487-semiplaning-boats-can-meet-many-needs

From Soundings Magazine,
"In the simplest terms, the semiplaning hull bears little resemblance to the displacement hull, but quite a lot of resemblance to the planing hull. As such, let’s compare the semiplaning hull with its full-planing counterpart."

I like that.
Most SD boats do resemble planing hulls more than FD. But I think it's just because they are more popular. Probably because most people would rather go quite a bit faster than FD .. not just a little bit. But the difference is more profound in reality than as expressed above. I prefer the just a little bit faster boats and they are almost non-existant. SD boats at the upper end are everywhere. Look right here on TF.

Of course now that boaters are so much more frugal w fuel dollars we see a lot more SD boats running just a little above displacement speeds or even at displacement speed.

If you don't want to talk about lift as it relates to this discussion, then you are basically pleading ignorance....and I mean that in the most respectful way. You are literally ignoring the most important factor....on purpose. Onward....no changing your mind.

What is missed time after time, there is no "line" to cross from one hull design to another.

Emphasizing only "parts" of boat design fails to comprehend the whole.

Like this article supported yet again, sometimes only very subtle differences are in the design, for reasons other than powering the vessel.

Fine entry forward, flat bottom at transom w shallow tunnel, hard chines

Jay wrote "leans out in a turn"

Wow, If a boat did that on sea trial I'd be say'in lets go back.

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It's the keel that makes it lean out. It's not like it's going to tip over.

jleonard said:

It's the keel that makes it lean out. It's not like it's going to tip over.

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Yep dang all those boars that lean out on turns...unseaworthy POSs....

Funny, come to think of it, I can't believe how many boats I have run or been on that do the same.........well st least some....

Jay,
I designed a 28' boat, built it and used it for awhile w/o a cabin. Kinda like sailboaters do when building a sailboat. They use it as a powerboat before they can afford the sails and rigging. And they are amazed at the different roll characteristics. My boat turned absolutely flat .. no bank w/o the cabin. It was kind of a tri. but yet a monohull. Or a cathedral hull. Anyway when I put the cabin on she banked moderately .. more like a normal boat.

I can only surmise that it was a CG function. Changed nothing, power or bottom wise .. just added the cabin. And she banked the same amount with or without wind. Only thing I can think of is CG.

I know boats w soft chines bank more than hard chines as the water exiting the hull out from under the inbd side sucked the inbd side down. But I made no change to the hull at all.


Keysdisease,
Thanks for the pics. She looks like a typical V type hull. Looks long and narrow but I'm sure it's the photo length of the camera lens. Not flat at the stern like the 34 but nearly so. I'm guessing the trim tabs are down in the lower photo.