PDA

View Full Version : What makes a boat strong



cc322
01-27-2004, 04:08 PM
We visited several boat builders at the show and I am curious what makes one boat stronger than the next. For example at Lavey we were told that the top and bottom are joined together in the mold, top flipped onto the bottom while still in the mold. Also they inject some type of foam between the floor and bottom also something about the stringers. Jeff said this will be felt when you hit rough water. Lavey had very good attetion to detail and really could not find one flaw in thier boats. Also thier is not as much wood used, they use several different molds one for the ice chests in the floor, one for the ice chest in the seats, cup holders, and the seats frame in the back was a seperate mold.We were also told that they will never cut out the center section of a cuddy to make it a walk through open bow, said it is done but it weakens the boat? If you want a cuddy there is a seperate mold, if you want a cuddy open bow , seperate mold . Does anyone have more knowladge than this? sure would like to hear it

rivercrazy
01-27-2004, 04:20 PM
To me lots of things will determine overall strength. And all these factors work together as a system to provide strength.
*Full length stringers properly installed in a boat.
*Quality and type of glass used
*Type of resin and how its utilized to bond the layers (properly catalized and given enough time to cure)
*Seperate open bow mold not just a cutout.
*How well the top and bottom are bonded
*How bulkheads and other supports are engineered/installed
*How are the gas tanks installed (Just glassing them to the hull sides are not a strong as building seperate supports that the gas tank bolts to)
* I think foam may help keep a boat quieter but I don't think it adds much strength. In fact, since it absorbs moisture, it could lead to rot.
*Whether the floor is glassed over (stronger) versus resin flo coated.
etc....

cc322
01-27-2004, 04:28 PM
We were told that they use only top of the line materials in there boats from resins, to fiberglass, to the nuts and bolts

cigarette1
01-27-2004, 04:49 PM
Pretty damn strong :D

Tom Brown
01-27-2004, 05:16 PM
Originally posted by cc322
What makes a boat strong
Rivets http://www.***boat.com/ubb/icons/icon14.gif

welk2party
01-27-2004, 06:32 PM
Pretty mcuh all the reputable builders use similar techniques. I don't think any one thing makes one boat stronger than the other. Materials are part of the equation but so is cure time and the conditions in which the cure is happening. Who is laying it up and are they having a bad day. Minor I know, but we are talking hand laid custom boats.

Jbb
01-27-2004, 06:35 PM
Originally posted by Tom Brown
Rivets http://www.***boat.com/ubb/icons/icon14.gif
The amount of Bran....in grams..... in the gelcoat....:eek:

K9Blitz
01-27-2004, 06:50 PM
Stop by Essex and aske to see the hull cut-out that stopped a 9mm bullet. They also glass in a product called Klegecell into the sides of their hulls. Makes them sturdier and quieter.
Overall boat weight will give some indication of the amount of materials used to build the boat. Some builders use 1/2 inch wood for their floors, while some step up and use 3/4. Also, the less amount of glass/resin material the lighter the boat.
I do most of my boating on Mohave, so a heavier duty hull is more important to me because of the chop. The Essex weighed in about 800 to 1000 pounds more than some of it's high-end competitors which made it the right boat for me.
If I did most of my boating on calmer water, I would go for the lighter/faster super low freeboard rocket.

cc322
01-27-2004, 07:03 PM
what essex do you have?

K9Blitz
01-27-2004, 09:12 PM
I have the 24' Valor. I had it out on Mohave a few weeks ago in 40 + mph winds, killer chop and whitecaps. It did great. It's a heavy boat (4500lbs) and handles great. Some of the lighter 24 - 25's may get better top end, but I'm happy doing 70mph and plowing right through the ripples.
Whatever you decide, get the most motor you can afford. I went with the 496HO/Bravo 1 X-drive and am glad I did. I read a recent study that proved the bigger motors don't have to work as hard to push the same amount of boat, meaning a smaller (supposed better gas mileage) motor burns the same if not more gas to push the boat the same as the bigger one. This was from the February 2004 issue of "Boating" magazine.
Good luck

cc322
01-27-2004, 10:00 PM
Just looked up the 21 Lavey it is 3850 with the small block ,so with the 496 i bet its close to 4000 lbs, pretty stout for a 21-23 foot boat:D

Froggystyle
01-28-2004, 12:02 AM
Originally posted by welk2party
Pretty mcuh all the reputable builders use similar techniques. I don't think any one thing makes one boat stronger than the other.
Today.... ;)

Kilrtoy
01-28-2004, 12:06 AM
WES
Your wife gave my wife plenty of jello shots at the June OP6 , I would like to meet you one day.......

Froggystyle
01-28-2004, 12:35 AM
You going to the show this weekend?
Drop me a PM...

Steamin' Rice
01-28-2004, 08:41 AM
Originally posted by cigarette1
Pretty damn strong :D
I LOVE what you've done to the cabin... Very nice finish!! Can't wait to see that bad boy in person.....:D

OGShocker
01-28-2004, 09:17 AM
Originally posted by RiverDave
Wes, give us a lesson on the
Uni-directional fiberglass
Bi-Directional Fiberglass
and I think tri-directional.. whatever..
For us lowly shoppers most of us (as evident in this thread that's been up for 2 days) dunno what all that shiznit means.
I can tell ya what boats are strong vs weak becuase I've ridden in em over rough water etc.. and seen some shaking like a ***** in church, and others making that "thud" and movin on... etc..
RD
RD,
Start a "best and worst" boat thread! That won't stur up any sh*t....LOL...;) :D ;)

cc322
01-28-2004, 09:20 AM
which ones are they riverdave ??????

rivercrazy
01-28-2004, 09:26 AM
Not all boat builders use the same materials, glass, resins, methods. That is what seperates the better builders from the average builders. Knowledge and experience are also just as important :D Sometimes its what you don't see that makes all the difference

spectras only
01-28-2004, 09:42 AM
x

Havasu_Dreamin
01-28-2004, 09:42 AM
Keep in mind, this is based on my own research when looking to buy a new boat in 2000 and Wes will have way more knoweldge than I could ever have on this subject.
Types of glass (in terms of direction of the glass):
Random: this type of fiberglass when you look at it just has the fiberglass going in many different directions, there is no pattern to the "madness"
Bi-Directional: this type of fiberglass has the glass laid out in a pattern follwoing two directions, vertical and horizontal, and are interwoven.
Tri-Directional: this type of glass is essentially the same as bi-directional except now instead of having a glass pattern on two axis it is now on three axis'. Again, the glass is interwoven.
Quad-Directional: also referred to as quad-axial becasue it is fiberglass interwoven on 4 different axis'.

spectras only
01-28-2004, 09:44 AM
[QUOTE]Originally posted by spectras only
[B]QUOTE][i]Originally posted by RiverDave
seen some shaking like a ***** in church, and others making that "thud" and movin on... etc.. "THUD" , that's the measure of a strong hull,hehe . You ride in my 24 spectra and that's the sound you'll get . Built like a sherman tank , slower than the new boats .Four full length stringers make a difference
:cool: BTW , maybe Halletts are so popular cause Bud Bailey has been their chief designer in the past;) :p

Froggystyle
01-28-2004, 10:45 AM
HD is absolutely right on the descriptions. Good Job! BTW, I know very little about the actual materials, but I have hired the preeminent experts in the field to do the layup schedule for us.
What Dave was referring to is the fundamental differences I found between the different types of mat and the technology that is available.
The problem with woven mat is that it traps a ton of resin, and resin is non-structural for the most part. Without going too far into it, the glass fiber is strongest as a single strand that is straight, not bent. When you weave a set of strands, you gain a lot of strength over a single direction though, because a single direction layer will crack when pressure is applied width-wise. The problem with a weave, is you take away a ton of inherent strength in the glass by bending it (by weaving) and then making it hard with resin. It creates millions of little stress points. In addition, the little voids in the glass matrix created by the weave itself need to be filled with.... that's right. Non-structural resin. The average wet-layout hull construction has about a 67 percent resin volume... meaning obviously that only 33% of the volume of the boat is structural fiberglass. And, conversely about 50% of the total hull weight is non-structural, non-functional resin.
One way we are building parts of the Revolution is by using what Dave referred to as "uni-directional" glass. This is glass that all runs in parallel lines and is held together by magic it appears. There are no weaves, and nothing to affect it's linear strength and resistance to stretching. One of the best things about this method, is that each fiber, when taken on a microscopic level needs only a very small amount of resin to achieve maximum possible strength. This number reduces when you overdo the resin, as is very common in our favorite "Super sturdy" constructions. (Sorry Brent ;) ) Sometimes by half. If you have any questions regarding this fact, try to break a piece of fiberglass vs. a piece of resin. The resin will crack nearly effortlessly, regardless of thickness. A cored fiberglass sandwich will not. This single layer is not very strong for use in a panel unfortunately. It's "fiber volume" is extremely high though. Something around 80% fiber to 20% resin. Super light, super strong... in one direction. The solution to this is multiple layers of uni-directional glass, in a custom layed construction. You will still see the four axis construction, but it will be done with individual layers instead of one single handy piece of Quadraxial glass or Knytex. The end result is approximately 70% fiber volume when layed up like this, and 30% resin, for a huge weight savings, and monster strength increase. Weight is power, weight is fuel economy, strength is durability. This, combined with some proprietary layup stuff we are doing is going to result in an extremely stiff, very quiet, very durable hull layup.
Thanks for asking! hehe...

Essex502
01-28-2004, 11:55 AM
Originally posted by Havasu_Dreamin
Keep in mind, this is based on my own research when looking to buy a new boat in 2000 and Wes will have way more knoweldge than I could ever have on this subject.
Types of glass (in terms of direction of the glass):
Random: this type of fiberglass when you look at it just has the fiberglass going in many different directions, there is no pattern to the "madness"
Bi-Directional: this type of fiberglass has the glass laid out in a pattern follwoing two directions, vertical and horizontal, and are interwoven.
Tri-Directional: this type of glass is essentially the same as bi-directional except now instead of having a glass pattern on two axis it is now on three axis'. Again, the glass is interwoven.
Quad-Directional: also referred to as quad-axial becasue it is fiberglass interwoven on 4 different axis'.
4 axis? X - Y - Z - ?? What's the fourth? Rotational? :D Time? (as in 4th dimension) :D

Froggystyle
01-28-2004, 02:18 PM
4 directions on a flat plane... Smartass ;)

Essex502
01-28-2004, 03:09 PM
Originally posted by Froggystyle
4 directions on a flat plane... Smartass ;)
har, har, har,har :D
Us scientific types (HD included - he's a rocket scientist!) think in 3 space axes! Right hand rule and all that. :D

Havasu_Dreamin
01-28-2004, 03:29 PM
I think?? :eek: :p

MagicMtnDan
01-28-2004, 04:25 PM
Originally posted by RiverDave
Us good machinist types.. think in 5 or 6 axis.. ;) (not axes)
RD
Nope, sorry RD. The plural of axis is axes. As in 5 or 6 axes ("ak-zeez")
ax·is ( P ) Pronunciation Key (kss)
n. pl. ax·es (ksz)
A straight line about which a body or geometric object rotates or may be conceived to rotate.
Mathematics.
An unlimited line, half-line, or line segment serving to orient a space or a geometric object, especially a line about which the object is symmetric.
A reference line from which distances or angles are measured in a coordinate system.
A center line to which parts of a structure or body may be referred.
An imaginary line to which elements of a work of art, such as a picture, are referred for measurement or symmetry.
One of three mutually perpendicular lines that define the orientation of an aircraft, with one being along its direction of travel and the other two being perpendicular to the direction of travel.
A line through the optical center of a lens that is perpendicular to both its surfaces.

spectras only
01-28-2004, 05:37 PM
RD , don't worry MMD is just splitting hairs :p . Axis is the term in the industry ,regardless of how many there is ;)

HOSS
01-28-2004, 06:50 PM
Speaking of axis,,,,,the North and South Poles are a detremental part in resin strength during layup just from a gravitational "settling" of fibers and resin. So inherently the fibers should set up longitudinally with respected fibers/strands.
Just another tip from your buddy HOSS! Moonlight and grasshoppers my friend.;)

Tom Brown
01-28-2004, 07:59 PM
HOSS, do you keep your razor blades in a cardboard pyramid to keep them sharp?

HOSS
01-28-2004, 08:02 PM
Which ones would stay sharpest? Given a full 24 hr period lets say last 24 hr period central timezone.

Tom Brown
01-28-2004, 08:20 PM
You have to suspend the blade perfectly in the center of the pyramid, without it touching anything, and two corners of the pyramid have to be lined up perfectly with the north and south poles. If anything is off by as much as an atom, the test is flawed.
Also, I think it helps if there is an ovulating woman in the vicinity. Not for the pyramid thing, though...

HOSS
01-28-2004, 08:53 PM
But even the material used for suspension would flaw the test. We would have to do it in a closed environment at one atmosphere.
In zero gravity would your balls hang or suspend?

quiet riot
01-28-2004, 09:56 PM
building it with aluminum!:D
jd

Essex502
01-29-2004, 07:36 AM
MMD and RD are both right...
When referring to a machine tool "5 Axis" is the correct terminology but when stating, as I did: "I think in 3 AXES" is correct as AXES is plural of AXIS. "5 AXIS mill" is a term used correctly too.
RD - What abot 7 axis machine tools?

Essex502
01-29-2004, 09:52 AM
RD -
See this 7 Axis Machine Center (http://www.usedmachinerysales.com/picture/2032.html)