Composites (F.R.P ½ model)

Fibre-reinforced plastic (FRP) (also fibre-reinforced polymer) is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually fibreglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic. FRPs are commonly used in the aerospace, automotive, marine, and construction industries.

Fibre mats

Web-form non-woven mats of glass fibres. Mats are manufactured in cut dimensions with chopped fibres, or in continuous mats using continuous fibres.

Chopped fibre glass

Processes where lengths of glass threads are cut between 3 and 26 mm, threads are then used in plastics most commonly intended for moulding processes.

Glass fibre short strands

Short 0.2–0.3 mm strands of glass fibres that are used to reinforce thermoplastics most commonly for injection moulding.

Advantages and limitations

FRP allows the alignment of the glass fibres of thermoplastics to suit specific design programs. Specifying the orientation of reinforcing fibres can increase the strength and resistance to deformation of the polymer. Glass reinforced polymers are strongest and most resistive to deforming forces when the polymers fibres are parallel to the force being exerted, and are weakest when the fibres are perpendicular. Thus this ability is at once both an advantage or a limitation depending on the context of use. Weak spots of perpendicular fibres can be used for natural hinges and connections, but can also lead to material failure when production processes fail to properly orient the fibres parallel to expected forces. When forces are exerted perpendicular to the orientation of fibres the strength and elasticity of the polymer is less than the matrix alone. In cast resin components made of glass reinforced polymers such as UP and EP, the orientation of fibres can be oriented in two-dimensional and three-dimensional weaves. This means that when forces are possibly perpendicular to one orientation, they are parallel to another orientation; this eliminates the potential for weak spots in the polymer.

Curve reinforcement

1 layer : Glue powder
2 layer : Double bias fiber
(put puplin on the DBS and pull it off when it is dry)
3 layer : bulk

Actually the glue powder I maxed was too running to shape the curve.

Outboard Engine Bracket

top 2 bolts are located by 72mm from top,distance between them is 327mm.
bottom 2 bolts are located by 312mm from top,distance is 250mm.
cutting list:
top wide 550m x high 450mm x bottom wide 400mm
because the transom angle is 12 but I found that it was approx 11,I have to adjust the bracket's angle to fit into 12, that is annoying!!!!

This motor is designed to be installed on boat transom with the the thickness between 41-70mm.
 

Transducer

I need to place a transducer below the engine box.
And I also need to do some reading about it.
these references would be helpful


We decide to use circle shape of hatch for transducer 
the size :





http://forum.woodenboat.com/showthread.php?113824-Transducer-question
http://www.interphase-tech.com/art/PR/Advisor1.PDF
http://www.boatersland.com/rayducers.html
http://www.freepatentsonline.com/4938165.html

A transducer is a device that converts one type of energy to another. Energy types include (but are not limited to) electrical, mechanical, electromagnetic (including light), chemical, acoustic or thermalenergy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a transducer. Transducers are widely used in measuring instruments.

Thru-hull(I think this trade term would be more meaningful)  transducers are mounted through a hole drilled in the bottom of the boat and protrude directly into the water. This type of transducer generally provides the best performance.

Thru-hulls are recommended for displacement hulls and boats with straight-shaft inboard engines. You'll also need a fairing block that allows the transducer to be mounted properly. Thru-hull transducers must be installed with a fairing to ensure proper alignment and a secure fit.

Thru-hull transducers must be positioned in front of the propeller, rudder, keel or anything else that may create turbulence. They must be mounted in a position that is always underwater and angled straight down.

Raymarine Transom Mount Transducers

As the name implies, transom mount transducers are installed on the boat's transom, directly in the water and typically sticking a little below the hull. Transom mounts are composed of plastic and tend to be less expensive than other transducers.

Transom mount transducers are recommended for planing hulls of less than 27 feet (8 meters), such as personal watercraft and powerboats with outboard, inboard-outboard and jet drives. They are not recommended for large or twin screw inboard boats because 'rated water from the propeller reduces performance. They are also not recommended for operation at very high speeds.

Transom mounts adjust to transom angles from 3¦ û 16¦. For angles greater than 16¦, a tapered plastic, wood or metal shim will be needed. However, the transducer should be adjusted so it is angled slightly forward when the boat is in the water.

Composites FRP

Day Skipper 1 9/8/2011

 It was a very impressive start that Brett linked the video of "Yacht dismasted by supertanker off Cowes" from YouTube.
 "Safety in Small Craft" is really a important and essential skill to handle if you want be a boatie.To be a boatbuilder, grasping this kind of knowledge seems like icing on the cake.
  We have learned the boat's equipment,Navigation,Rules of the Road,Ropework and The weather etc  ,but most impressive is the Navigation which talks about how to read the chart.There are a lot of Chart symbols in this chapter.These terms are very useful for boaties.There are also something very complicated to me like The part of Measurement of distance and speed which has a totally unfamiliar terminology -- "nautical mile ".          

Reading Report of Chapter 17 of The Gougeon Brothers on Boat Construction

Mold(temporary) frames and Permanent Frames

Well I already read most of this chapter these days and figured out that there was a different technique for the frame setting up and shape transferring.
I think it would be the same thing as Tiger's group but not like what we have done for ours because we just made the temporary frame for our dory. It is still valuable 
for us to learn this technique.