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.
   

Small craft building Day 4 temporary gunwale

Before making the gunwale we have to get a temporary one for it because we need to figure out the size of plywood for topside and we could also see the shape and adjust both side of the boat.  
For the temporary gunwale we could use pine for it as it is just temporary.

Gunwale size : L(4100mm+),W(15mm+),H(25mm+)
Cutting list
L:5100MM
W: 280mm
H:  85mm

Use table saw to cut it into the size we need and put it through the Thicknesser.

well we get it!

We need to know how much plywood we need for both side so we have to figure out the location of temporary gunwales
Firstly, screwing the temporary gunwale on the the custom-wood with some blocks.

Secondly,using a pattern to estimate the size of plywood for both side.
Thirdly,transferring the dimension on plywood and making scarf joint with plane.


                            

 

Next, put resin on plywood and glue them.When it occurs we could sand them flat with sander then nail them on the side of the frames if the shape is fine we could glue them.Making sure that plywood could go above onto stem with the right angle and cut the more out.After the plywood being glued ,we could clean up the glue coming out from inside and outside.

Small craft building Day 3 about the transom

 I lofted the transom but this transom's lofting was bit difference with the lofting I have done before.I realized that the transom's sickness combined the plywood and fashion piece.Under Merf's help I figured out the plywood with 6mm sickness and the fashion piece with 20mm.
  Well although I don't need to loft them out but I have to know where are they and how will they fix together.

This would be a good way to cut it out

( Below )

This is the cutting list of the fashion piece of transom.
I used AutoCAD to lay it out that would be easy to understand.

   Ok,it's time for transferring the transom onto the plywood of 6mm.

I need :
small batten
steel rule
pencil and rubber
nils and hammer

Attention :
the ratio of the camber is 1:12.4 (from ACAD)
the scale 1:4
the distance between edge of the board and drawing is 10mm.

after drawing I will cut it out by band saw and plane the edges.

Small craft building Day 2

Well we have done the strongback and all the frames of drawing on the MDF today. I made a mistake of measurement when i was drawing frame of STN 2 and also cut that board too much while using that band saw.

But today was not too bad to me cuz I reviewed the lofting knowledge of transom.:)
  

The small craft building day 1

We upgraded our Dory from 3.6M to 4M.  :)
I think we spent too much time on making the extension of the table but it is really  essential as well.

Cutting list of that extension of strongback 
2 braces (small)
Legs 810mm(high) * 4 pcs
braces inside 810mm(length) * 2 pcs
extension bar 1000(length) * 2 pcs
screw block * 4 pcs 

Next we selected 3 pcs of MDF(Medium Density Fiberboard) of 2440mm * 1220mm

Transferring the drawing from CAD printed onto the boards . It needs our absolutely accurate drawing!!
It would be very annoying if we get some mistakes.

All done but unfortunately we got one piece of waste as the inaccurate drawing.

  Next step we are going to set up these frames on the strong back.

  Making some blocks like wedges and screwing them on the strong back with 2 pieces every single side.

 





Making some braces and screwing them between the frames for strengthening.

  

lofting day

"Before you can actually build a boat,you must loft its lines to full size."

The first step in lofting is to lay out the grid for the three views.The grid is the general name denoting all of the straight lines that represent the location of the buttocks,waterlines,centerlines,and station lines.
(be sure of that the measurement should be very accurate)

When all the straight lines are finished the next step is to draw the curved lines.I begin with sheer line.Go to the table of offsets for the profile view,given in distances from the centerline.Then at each station line,carefully measure the dimensions from the Cl given in the offsets.Lay a fairing batten on these points.

To make sure the batten can touch every point by its edge i use nails to hold it there.

we are going to make oilstone box

this is the one that I grabbed from interent.












1 cutting list
2 processing
3 machinery needed

the first 2 weeks

This is the final look of my tool box.

    We had finished the Tool Box making on Wed this week I was the last one to leave so I shot some pictures on our ultimates.

deeply appreciate Merf's direction and the whole teammates'help.

other guys' followed...