adding material to section, making taller and long

[gw204]

Mike,

You're aware that the 2520 has a step-down at the back edge of the pilothouse, right?. If you lengthen it, you'll have one section with more headroom that another unless you do some work to the floor also.

[reddrum_com]

I used the Parker picture since everyone knows Parker and the picture was good and easy to use. The boat I'm buying is a 25' C-Hawk.

Oddly enough on the older C-Hawks the pilot house is only 5' or so tall inside. Who knows why they did that. I think I can fix it tho ;-)

If this were a car I'd chop away and know that I can do it. Since its a boat I wanted to make sure there isn't something I don't know.

Thanks for any advice!

mike

[warthog5]

Oddly enough on the older C-Hawks the pilot house is only 5' or so tall inside. Who knows why they did that. I think I can fix it tho ;-)

A lot of times it's kept low for 2 reason's.
To keep the windage and top heavyness down.

The other reason is to make it look right. A short length boat can get out of proportion.

I understand why you want to do it. It can make a big diffrence if you reall get the lines out of proportion.

How tall are you? The underside of my hardtop is 6ft-4in.
The cuddy height has been pushed to the max limit, and still keep's the lines of the boat looking right.

I'm wondering what the core material is, if any now in the side's of the pilothouse?



http://www.classicmako.com/projects/xshark/

[Ed]

Redrum-

If I were you, I would make the main cuts where you see fit than I would grind back 8 inches on either side of the entire main cut on the "outside" of the pilothouse. Next, on the "inside" of the pilothouse I would take a circular saw or something similar and set depth of blade to just shy of the thickness of the core...(maybe 3/4 of an inch. Not too deep because you dont want to cut all the way through!) I would then, using the circular saw, make a cut line 4 inches all the way around above the "main cuts" and then again 4 inches all the way around the bottom of the "main cuts".

Then I would remove the 8 inches of core between the two cuts. Next, I would get some 2x4's and bolts and I would temporarily bolt the cut sections of the pilot house back in place with the 2 x 4's and make sure it is plumb and level before you start glassing.

Once you are okay with the layout, I would get some core that matches the original (again, maybe 3/4 inch ply?) and I would cut it to size (taking into account how many inches you extended up and aft). Once the plywood is cut, dry fit a couple of times to make sure it fits 100%. Once you are okay with the fit, mix up some epoxy with cabosil and trowel it onto the inside section of the pilothouse where you removed the core. Next, press in place the core and clamp or bolt it down until the epoxy cures.

Once it has cured, cut yourself some 1.5 oz mat that is slightly bigger than the new core section (maybe 3 inches larger all the way around) and lay it up on the inside. Follow this with a piece of 1808 biaxial that is 4-5- inches larger than the core and lay it up on the inside as well. Finally, follow up with another piece of 1.5 oz mat that is 6 inches larger than the core. This should take care of the inside for now.

Next, move to the outside and follow the same layup schedule. (Depending on where/how your temporary 2x4 staging is setup...you might have to swap it over to the inside so you can now work on the outside.)

The only thing that is hard to say for sure is the actual number of layers of glass you'll need. It all depends on how much glass the factory used originally to make the pilot house. If you use too much glass to piece the pilot house back together you will be grinding forever...if you use too little, it wont be very strong and you will be putting on a lot of epoxy fairing compound to raise up the height.

Again, this is pretty complicated to explain over the net, but I am sure you get the picture. Also, I am sure Bobby (WARTHOG) will have some specific suggestions too. The guy built his own pilothouse on his 23 Mako.

Good luck and take your time and measure 3x before you cut anything!

Ed

[salvagefirst]

strange someone mentioning C-Hawk ,i was at the C-Hawk plant yesterday. Dont worry about adding weight to the top. the hull on your boat is the same hull built today, out of the same molds that 25 hull is used in the pilot, standard cabin, and the sport cabin. the sport cabin is taller and longer cabin than the pilot and weighs 300 pds more. the only core materials i seen was marine ply. the transom, floors, stringers are all hand layed marine ply screwed together in a grid system than shot with the chopper gun. A very solid built boat. there is some info on www.chawkboats.com