From what I can determine, once a boat is on plane, it is primarily
the weight that determines fuel efficiency so a lighter weight boat
should give much better fuel economy.
BUT, as I have found with my Tolman which is very light for her size,
a lightweight boat is easily pushed around by a wave due to less
momentum. So, although you might consider a boat made from new
lightweight composites, would it be as seaworthy as a heavier one?
This is actually a practical consideration for me if I build a Tolman
Jumbo with slightly gretaer deadrise than the design. More deadrise
will make her pound less but will the lightweight make her less
seaworthy than similar heavier boats?

Frogwatch wrote:
From what I can determine, once a boat is on plane, it is primarily
the weight that determines fuel efficiency so a lighter weight boat
should give much better fuel economy.
BUT, as I have found with my Tolman which is very light for her size,
a lightweight boat is easily pushed around by a wave due to less
momentum. So, although you might consider a boat made from new
lightweight composites, would it be as seaworthy as a heavier one?
This is actually a practical consideration for me if I build a Tolman
Jumbo with slightly gretaer deadrise than the design. More deadrise
will make her pound less but will the lightweight make her less
seaworthy than similar heavier boats?


Build it out of plate aluminum with a deck and sealed flotation chambers
underneath. Drive slowly down the side of the road and gather up empty
aluminum sodapop cans, roll them out and weld them together.

On Mon, 29 Jun 2009 11:19:01 -0700 (PDT), Frogwatch
wrote:

From what I can determine, once a boat is on plane, it is primarily
the weight that determines fuel efficiency so a lighter weight boat
should give much better fuel economy.
BUT, as I have found with my Tolman which is very light for her size,
a lightweight boat is easily pushed around by a wave due to less
momentum. So, although you might consider a boat made from new
lightweight composites, would it be as seaworthy as a heavier one?
This is actually a practical consideration for me if I build a Tolman
Jumbo with slightly gretaer deadrise than the design. More deadrise
will make her pound less but will the lightweight make her less
seaworthy than similar heavier boats?

I'm not an engineer, but I'll guess a bit.
Yeah, weigh affects stability, and there's no way around it.
But, hull design can help as far as wave action.
The cat-type hulls on that Intruder seem to cut water and hold
direction to some extent. Didn't seem to pound badly, but I think you
have to be there doing a kidney-check to really tell.
Seems to me the major problem with a lighter hull will be the
"cork-like" aspect of bobbing up and down.
Anyway, I was thinking inshore boats more than ocean-going.
Fishing and other recreation boats.
The Intruder videos said they were in 8' seas.
Don't know if that was true.
But again, I'm not looking for a heavy weather boat.
I'll bet 90% of recreational boating miles is in good weather,
and 99.9% is in decent weather.
Can't make a perfect boat.
I was thinking along the lines of styrofoam-like weight.
Hardened on the outside with something light, and maybe
internally stiffened with something light.
Could even be made cheaply enough to throw away the hull
after not too many years.
Prettifying it and gussying it up will happen pretty quick for some,
but the Carolina Skiff has found a market for bare-bones, and an even
lighter boat will do it one step further.

--Vic

--Vic

On Mon, 29 Jun 2009 13:50:56 -0500, Vic Smith
wrote:

But again, I'm not looking for a heavy weather boat.

There are those who carry a .22 handgun. As long as they don't use it
the lack of stopping power doesn't matter. Or does it?

On Mon, 29 Jun 2009 18:07:03 -0500, Richard Casady
wrote:

On Mon, 29 Jun 2009 13:50:56 -0500, Vic Smith
wrote:

But again, I'm not looking for a heavy weather boat.

There are those who carry a .22 handgun. As long as they don't use it
the lack of stopping power doesn't matter. Or does it?

Don't know. I could say,
"But being as this is a .44 Magnum, the most powerful handgun in the
world, and would blow your head clean off, you've got to ask yourself
one question: Do I feel lucky? Well, do ya, punk?"

Or I could say "What's your point, Vanessa?"

But let me just get your recommendation for a heavy weather flats
boat.

--Vic

On Mon, 29 Jun 2009 18:26:34 -0500, Vic Smith
wrote:

But let me just get your recommendation for a heavy weather flats
boat.

No such thing really but a CS24 with a jack plate is about as close as
you'll get.

On Mon, 29 Jun 2009 18:26:34 -0500, Vic Smith
wrote:

On Mon, 29 Jun 2009 18:07:03 -0500, Richard Casady
wrote:

On Mon, 29 Jun 2009 13:50:56 -0500, Vic Smith
wrote:

But again, I'm not looking for a heavy weather boat.

There are those who carry a .22 handgun. As long as they don't use it
the lack of stopping power doesn't matter. Or does it?

Don't know. I could say,
"But being as this is a .44 Magnum, the most powerful handgun in the
world, and would blow your head clean off, you've got to ask yourself
one question: Do I feel lucky? Well, do ya, punk?"

Or I could say "What's your point, Vanessa?"

But let me just get your recommendation for a heavy weather flats
boat.

Vic

On Mon, 29 Jun 2009 13:50:56 -0500, Vic Smith
wrote:

I was thinking along the lines of styrofoam-like weight.
Hardened on the outside with something light, and maybe
internally stiffened with something light.

Yes, like a SeaRay !

(I can talk like that since I own one)

It's important to remember that "ride quality" and "sea worthiness"
are only loosely related. You can in fact take a boat with a hard
ride and make it better by adding weight. At the same time however,
freeboard is lowered which makes it inherently less seaworthy, and
possibly less stable depending on where and how the weight was added.
Also, fuel consumption will increase and speed will decrease.

There's just no free lunch here.

On Mon, 29 Jun 2009 21:09:53 -0400, Wayne.B
wrote:

On Mon, 29 Jun 2009 13:50:56 -0500, Vic Smith
wrote:

I was thinking along the lines of styrofoam-like weight.
Hardened on the outside with something light, and maybe
internally stiffened with something light.

Yes, like a SeaRay !

Well, the SeaRay isn't exactly what I was talking about.
Pretty heavy boat:
Overall Length : 19' 8" / 5.99 m
Beam : 7' 3" / 2.21 m
Draft - Stern Drive Down : 34" / 86.3 cm
Draft - Stern Drive Up : 17" / 43.1 cm
Dry Weight : 2,600 lbs / 1,179 kg
Fuel Capacity : 26 gal / 98.4 L
Dead Rise : 19° / 19°
Max Persons/Weight : 8/1,100 lbs / 499 kg
(MWC) Max Weight - Persons/Gear : 1,200 lbs / 544 kg
MerCruiser® 3.0L Alpha I MCM Sterndrive w/Turn-Key Start (135 hp)

Just for fun, and that's all, let's look at a similar size CS.
DLX 1980
Length: 19'
Beam 7' 9"
Draft: 3" to 6"
Finished Weight: 1533 lb.
Max Persons/Weight: 11/1970 lb.
Max HP: 115 HP
( A 115hp 4-stroke Yamaha weighs 402 lbs)
Battery - 50 lbs?
Weight with motor and battery: 1985 lbs.
A 90hp would do for some, but it only gets you to 369 lbs motor
weight. 75hp weighs the same. A 60hp gets you to 237lbs, but
is probably too weak. Depends on your personality, I guess.

But staying with the 115hp, that makes the SeaRay about 25% heavier.
BTW, the bare hull weight of the DLX1980 is 1100 lbs, according to
their "build your own" page, so I'm guessing the "finished weight"
means typical outfitting with CC, front and rear decks/compartments
and livewell(s).
Couldn't find an exact definition, but a thread on the CS forum
indicated that "finished weight" did not include motor/battery.
I'm sure the SeaRay is more "amenity-laden," hopefully has at least
marginally better quality glass and is a better riding boat
in the chop. Luxurious, you might say.
But if you are guided by the less weight = more economy formula you'll
go with the CS.
You might do without some of the decking/compartments to further
reduce the CS weight, add a little weight with a bimini and some
glassed in 2x4's to stop hull flexing. Not sure if that's an issue
with the CS 19's but I've read of flapping hulls at speed with the
24's.
Then there's the $12k or so price difference.
This is all ball park stuff from me.
Don't know the gas economy figures for the SeaRay, but CS owners
always seem happy with their fuel economy.
All that digression aside, I was thinking of something lighter than a
CS, which is after all standard FRP.
Even vacuum bagged, FRP isn't light enough.
That's where Froggy comes into the picture.
Some kind of deposition process is needed.
His forte.
Think of those robotic paint machines depositing paint on auto bodies.
But depositing something else into a mold and ending up with a boat
instead of a paint job.
Materials to be determined.
Of course maybe he's too busy with other concerns.
This is pretty interesting, if only to see the specific gravities of
white oak vs. red oak vs. balsa. (page 7)
http://www.shipmotion.com/pds/IBEXFlotation.pdf
Might answer some of the questions Froggy had about flotation
placement too.

It's important to remember that "ride quality" and "sea worthiness"
are only loosely related. You can in fact take a boat with a hard
ride and make it better by adding weight. At the same time however,
freeboard is lowered which makes it inherently less seaworthy, and
possibly less stable depending on where and how the weight was added.
Also, fuel consumption will increase and speed will decrease.

There's just no free lunch here.

Right. But a cork-like riding boat could be equipped with a water
ballast hull ala the Mac 26, to make the ride somewhat adjustable for
chop without radically compromising safety.
That's another economical non-displacement hull boat under power,
again mostly or entirely due to light weight, from what I can tell.

--Vic

On Jun 29, 2:34*pm, Gene wrote:
On Mon, 29 Jun 2009 11:19:01 -0700 (PDT), Frogwatch

wrote:
From what I can determine, once a boat is on plane, it is primarily
the weight that determines fuel efficiency so a lighter weight boat
should give much better fuel economy.
BUT, as I have found with my Tolman which is very light for her size,
a lightweight boat is easily pushed around by a wave due to less
momentum. *So, although you might consider a boat made from new
lightweight composites, would it be as seaworthy as a heavier one?
This is actually a practical consideration for me if I build a Tolman
Jumbo with slightly gretaer deadrise than the design. *More deadrise
will make her pound less but will the lightweight make her less
seaworthy than similar heavier boats?

By definition: flats boat. *Stay out of the waves....
--

Forté Agent 5.00 Build 1171

"Twenty years from now you will be more disappointed by
the things you didn't do than by the ones you did do.
So, throw off the bowlines. Sail away from the safe harbor.
Catch the trade winds in your sails.
Explore. Dream. Discover." * - Unknown

Grady-White Gulfstream, out of Oak Island, NC.

Homepagehttp://pamandgene.tranquilrefuge.net/boating/the_boat/my_boat.htm

Tolman reccomends a 60 hp engine for my 20' Tolman Standard because it
is so light. I went with a 90 hp 2 stroke but its weight plus the 9.9
kicker was enough that I had to place my batteries forward and run 00
gage battery cable (expensive) and I have to be careful to have my
passengers sit forward to balance here well.
So, what if I went with a 125 hp 2 stroke and placed my batteries even
further forward AND incorporated tanks that could be filled with
seawater to give her enough momentum to get through waves (also assume
more deadrise). She could be lightweight for normal conditions but
then heavy enough (by filling the tanks) for wavy conditions.