Sunday, October 30, 2011

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.
 

Monday, October 24, 2011

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



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.

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¦ รป 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.

Tuesday, August 9, 2011

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 ".          

Monday, July 25, 2011

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.