how thick the fiberglass?

[CarMan]

I am doing a hul extention on may Bayliner 3288.

How many layers of 450g fiberglass shud i hawe in the botom?
Shud i do only in fiberglass, or samting in betwen layers of fiberglass

 

[apex1]

Could you be a bit more specific? How long the extension, how do you support it (lengthened girders, stringers?), do you move the transom? and so on.....

 

[CarMan]

of course, it's not so easy to en what inside my head.

I will only extend swimplatform, so I do not move the rudders or something (the boat has straight axles)

Swimplatform is extended 4 feet.
My boet is stern hawy, and neds 4 trimlabel full down, so i am doing an hul extention below the swimplatform, is extention is 3 feet.
i am adding 2 trimlabels to it. its the only thing how is going to be monted on it.

The boat has propeler tounels and rouder is monted on the stern, so i need to do tounels on the new extention to. the rouders is outside the tounels when fully tilted, so i can not do rounded tounels on the extention.

her i som pictures.

one of the pictures is from an boat how has somting like tis don (foundit on internet)

 

[apex1]

Oh, uhh ahh, hmmm, yes!
I think that will become less a question of how strong the extension, but more how well engineered!?

have a look here:
http://www.boatdesign.net/forums/surface-drives/diy-tunnel-drive-20433.html

BAECKMO !!!!

 

[CarMan]

I am not mowing my rouders. ther is lots of 3288 how get tis extention don, and it do good! las ster heavy and you do not need so mutch trimlabel.

i am not like schort owerhan on hte swimplatform, so i am doing the swomplatform atleast 1 feet longdet then the hul extention. I am allso doing owerhan at the sides (you can se how in the privius picture)


my questien is, how do i do the hull, is it OK to do 6 layers of 450g fiberglas?
ore shud it be 4 layers and divysel, then 3 layers abow ?

how is the orginal hul construktion?

 

[CarMan]

Ather boats whid this type of construktion.

 

[apex1]

my questien is, how do i do the hull, is it OK to do 6 layers of 450g fiberglas?
ore shud it be 4 layers and divysel, then 3 layers abow ?
/QUOTE]

I do´nt know the original laminate, maybe someone else will chime in!? Do just a solid layup, no core! if you do as the others have done (shown in the pictures you do´nt have wide sections with unsupported skin, so you do´nt need additional stiffness (and that would be the only advantage of foem core). But foam is always in risk of water intrusion, that is just another risk you do not need. 6 layers should do the job very well in my opinion. It is fabric, no mat ja? In the 4th picture that looks like mat. Use fabric, mat is just weight but has not much strength.
Do not enclose the compartment forever and eternity! Make a inspection hatch / hole.

Regards
Richard

 

[CarMan]

i will do 2 "doors" for storage 70x70 centemeaters eatch

 

[apex1]

Perfect!
and this:>>>>It is fabric, no mat ja? In the 4th picture that looks like mat<<<<??

 

[CarMan]

I am not sure what you say.

i think you want me to use this:

not this.

last year i build a rof extenton, an i only use the thinf you cald Mat, i feedl werry strong.

can i go for 2 layers of mat 2 layers of fabric and last 2 laers of mat agen ?

and use som extra layers of fabric in all courners.

 

[apex1]

I am not sure what you say.

i think you want me to use this:

correct!

last year i build a rof extenton, an i only use the thinf you cald Mat, i feedl werry strong.

yes but that is mainly the resin the mat does not add much!

can i go for 2 layers of mat 2 layers of fabric and last 2 laers of mat agen ?

You can, but I do not recommend. Use one layer of mat outside (so, the fabric pattern will not "print through") than fabric/mat, fabric/mat, fabric, thats it. The mat between the fabric layers helps to avoid dry spots and air entrapped, but structural has not much effect.

and use som extra layers of fabric in all courners.

Thats right, make some soft corners, tabbed with cloth.

Good luck, lets have a picture when finished.

Richard

 

[CarMan]

the boat is sitll in water and will be for 2 month, then i can start.

 

[apex1]

We are patient here, enjoy your summer! Is too short anyway.

 

[Commuter Boats]

of course, it's not so easy to en what inside my head.

I will only extend swimplatform, so I do not move the rudders or something (the boat has straight axles)

Swimplatform is extended 4 feet.
My boet is stern hawy, and neds 4 trimlabel full down, so i am doing an hul extention below the swimplatform, is extention is 3 feet.
i am adding 2 trimlabels to it. its the only thing how is going to be monted on it.

The boat has propeler tounels and rouder is monted on the stern, so i need to do tounels on the new extention to. the rouders is outside the tounels when fully tilted, so i can not do rounded tounels on the extention.

her i som pictures.

one of the pictures is from an boat how has somting like tis don (foundit on internet)

Gentlemen, I hope you don't mind me joining in your conversation as I have a thought or two.
The obvious, making the extension the full 4 feet (or 3 feet 9 inches) of your platform would yield 33% more buoyancy with very little additional weight.
It would also be easier to board at the swim platform from a skiff if the skiff wasn't able to get under the platform as it would be if you recessed the extension by a foot.
I'm guessing from your photos that your three-foot extension would yield near 2000 pounds of buoyancy ( approximately volume 11x3x1 33 ft.³) and your structure will weigh between 3 and 4 hundred pounds... 1600 pounds additional buoyancy.
It seems that you've probably done your research and know that 3 feet works.
I agree that the unsupported square doesn't justify a core with an exception to the transom, I would core that or reduce its square by recessing the trim tab actuators.
I've done a bunch of variations but never one quite like this ( I've included a couple photos of one that I did that didn't add planing surface).
I'm a little surprised that the rudder doesn't misbehave in the examples shown.
Gerald

 

[CarMan]

I hawe not don anny calkulations. bur manny boat has this don, and som of them allso has ounderhulls (ounder hull, the boat has strate courners, not runded. It ad flotation to)

the boat is stern hawey, and the wxtention will help the boat to not be stern haewy.

the one i hawe talkt to say it is only goot thing to ad a awtention, but i am a litle worid aboa how it effekt turning the boat sidways (bow truster to starboard, rouders to port, starboer enging forvard, port enging back)

the extention of tonels can slow dom the water from starboard enging / thru the roder. (in may exampel)
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maby ai am ading a fueltank in the extention (it wold be nice to have 200 liters extra fuel)