77 MFG Gypsy Tri Hull rebuild

Blackstorm

Cadet
Joined
Jun 24, 2009
Messages
19
I have started the deck(s) removal and have reached the hull. It appears that there were two prevoius attempts at repairs both involving 3/4 plywood that went in untreated. The foam was soaked and the two strings were rotted out ( I expected this) and I am prepared to replace the stringers. Here are my questions so far.
The stringers were glassed in half heartedly how do I remove the glass back to the hull. (A) Grind it out and with what or (B) cut them or (C) Something else
When the foam was removed down the center of the boat there are sections of half round fiberglass (2-2 1/2" across) that appear to channel water to the bilge area. Do I want to keep this in place or remove, there are open sections which I think are used to collect and channel water to the bildge. I will take pictures tomorrow as I am digially challenged my wife will help me load them up.
On the above waterline sections of the boat there were several holes put in it that I no longer need is it acceptable to use auto body (Marglass) to patch the holes or do I need to epoxy these like the floor.

I will limit my first post to these three questions. BTW I love these forums and all of the information they possess.
Thanks
Glynn
 

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

hi bud......welcome to i boats.....best boating forum in the world.....this place is boat university.

impossible to tell with out pics....but im guessing that you leave the channels...instead of the autobody filler.....use marine tex....(this is an epoxy based patch)

and speaking of "epoxy like the floor".....why not just use polyester resin?.....it will cost you half the price and last 25 years.

we can all give you more info when we see the pics....they really help with restos.

cheers
oops
 

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

oh....as far as the stringers....cutting them with a saws all. works great as the blade will make a straight cut close to the hull....remove the rest of the carp with the grinder......(rubber backing pad....and 24 grit discs)

please read safety basics of grinding and glassing in the info sticky at the top of this forum.......(if its not there search "safety basics of grinding and glassing")

cheers
oops
 

Blackstorm

Cadet
Joined
Jun 24, 2009
Messages
19
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

th_IMG_0865-1[1].jpg

IMG_0864-1[1].jpg

th_IMG_0862-1[1].jpg

th_IMG_0863-1[1].jpg

Here are the pictures of the Hull and the tunnel that runs down the center of the boat and the gap in the tunnel.
 

keepNitreel

Chief Petty Officer
Joined
Aug 21, 2008
Messages
446
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

I miss placed my microscope :D, is it possible to post some bigger pic's, like 640X480?
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,064
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

Welcome to iboats.

MFG boats are great and restoring it will make it better than new.

Oops has you on the right track. A word of caution be careful not to cut through the hull (which many have done before you) with a tool and please take proper precautions.... we like to mention safety ;)

That channel is the path for water drainage and you will see ways to enhance that as you move along in your progress.

Thank you wife for the photos! We do allow larger ones and information about posting photos (for your wife to read since you are challenged) is located here in the top three threads http://forums.iboats.com/forumdisplay.php?f=32

Hey enjoy!
 

Blackstorm

Cadet
Joined
Jun 24, 2009
Messages
19
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

Here are the next set of resized pictures showing the hull and that tunnel down the center of the boat.
Next question I have is the foam did not contact the bottem of the untreated plywood that was used when it was manufactured and had pooled water on it. There does not appear to have been too much of the expanding foam used in most parts of the hull less than an inch. Was this normal for the 1970's and I doubt it offered much in the way of flotation. I plan on using the blue rigid foam from Lowes. should I leave an air gap or should I use this foam as part of the structure? I plan on coating the plywood top and bottom and using 2 oz cloth on top carrying it up the sides of the boat.

Another question on filters for the breathing mask are the HEPA filters used for asbestos removal acceptable they are good to less than 1 micron, but I don't know what size particles I will create with grinding. I plan on cutting the fiberglass used to hold in the stringer as close as possible to the hull before grinding.
thanks
Glynn
 

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PiratePast40

Lieutenant Commander
Joined
Mar 21, 2009
Messages
1,734
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

As for the respirator cartridges: You want to look for cartridges with a magenta stripe on them or with a black stripe and a magenta stripe. These are particulate cartridges. The standard is for removal of 0.3 micron sized particules but down to 1 micron is fine. The important thing is to make sure you get a good seal to your face and you take care of the respirator. You should remove the cartridges and wash the facepiece daily after use. Make sure you inspect it every time before use. Please don't try to copy the guys in the movies and wear the resprator around your neck. You'll be getting the stuff inside the facepiece and then suckng it into your lungs when you put the resprator back on. Basically, if you can taste the stuff you're grinding, it should be obvious that you don't have a good face fit.

Good luck with your project - you've got plenty of help here when you run into problems.
 

Lightnig

Petty Officer 2nd Class
Joined
Jun 7, 2009
Messages
189
Re: ?? on replacing the deck on a 77 MFG Gypsy

Re: ?? on replacing the deck on a 77 MFG Gypsy

For cutting the deck and stringer I used a 5" angle grinder with an 3/32" steel grinding blade. Cut through the glass like it wasn't even there. I laid it down so the blade was parallel to the hull and sliced through the bottom of the glass on the side of the stringer. After I pulled the wood out (the stringer came up in one piece), it left two little vertical 'stubs' of glass that I ground down with the same grinder but with a 36 grit flap wheel, which I also used to prep a soft spot on the keel that was leaking water.

It took less than two hours to cut out the floor, and another 1 hour to 90 minutes to pull the stringer. Still haven't fully finished cleaning up the old glass though. I got fed up with grinding and decided to start chasing the hole in the hull instead. :D

shush oops!, I've been catching up on your 'stretch job' thread the last couple of days, I can't even come close to your patience for grinding... ;)
 

Blackstorm

Cadet
Joined
Jun 24, 2009
Messages
19
Latest questions on 77 MFG Gypsy

Latest questions on 77 MFG Gypsy

Latest Questions for 1977 MFG Gypsy Tri Hull
Two questions on stringers
1. What method should I use in making a stringer longer than 8' I am using 3/4" marine plywood but it is only 8' and I need about 9- 9 1/2'. Half lap joints? or something else?

2. Do I need to put the cross braces between stringers in exactly the same way as original to keep structural integrity( there was originally no cap to the plywood). Or can I flip them on their sides and create a larger nail surface for the deck?

One ? on Foam
Foam question took out less than two half full bags of waterlogged foam from the hull and sides of the boat. I am planning on putting in the blue sheets from Lowes do I have to attach them to the hull? Is there any reason why I can't attach them to the bottom of the glassed plywood and keep a small air gap betweem the foam and the hull. I suspect I am putting in 2X as much foam as I took out but what is recomeended for floatation purposes.

Last Question is on the bilge area
I have a fiberglass tunnel that runs down the center of the boat and supposedly drains into the bilge box. The area's on both sides of the stringers had no way to drain to the bilge area. Do I notch the stringer in the rear or some other location or multiple locations to get what water enters the hull outside of the center section a place to go? I plan on glassing both sides and the top of the stringers so I need guidance before I start creating more sawdust.
I know a lot of questions and I did searches but found no suitable answers
Thanks
Glynn
 

Blackstorm

Cadet
Joined
Jun 24, 2009
Messages
19
77 MFG Gypsy Tri Hull rebuild

Latest Questions I have cleaned out the old foam and I am about to start the stringers.

Two questions on stringers
1. What method should I use in making a stringer longer than 8' I am using 3/4" marine plywood but it is only 8' and I need about 9- 9 1/2'. Half lap joints? or something else?

2. Do I need to put the cross braces between stringers in exactly the same way as original to keep structural integrity( there was originally no cap to the plywood). Or can I flip them on their sides and create a larger nail surface for the deck?

One ? on Foam
Foam question took out less than two half full bags of waterlogged foam from the hull and sides of the boat. I am planning on putting in the blue sheets from Lowes do I have to attach them to the hull? Is there any reason why I can't attach them to the bottom of the glassed plywood and keep a small air gap betweem the foam and the hull. I suspect I am putting in 2X as much foam as I took out but what is recomeended for floatation purposes.

Last Question is on the bilge area
I have a fiberglass tunnel that runs down the center of the boat and supposedly drains into the bilge box. The area's on both sides of the stringers had no way to drain to the bilge area. Do I notch the stringer in the rear or some other location or multiple locations to get what water enters the hull outside of the center section a place to go? I plan on glassing both sides and the top of the stringers so I need guidance before I start creating more sawdust.
I know a lot of questions and I did searches but found no suitable answers
Thanks
Glynn
 
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