'72 Glastron GT160

[AMD Rules]

Re: '72 Glastron GT160

I'll see if we can come up with some warmer weather for you ADM, but at the moment we are a bit chilly, todays high is around freezing. I'm just hoping we don't have the 30 mile per hour winds to go with it again. We are going to thaw out this weekend, hopefully things warm up for you too!

Looks like you are still making progress! You should be good on the glassing, I didn't have any issues other than big layups (like the entire deck). The fumes can get pretty strong on big layups. I did most of my large layups in the summer with the doors open, but I did a lot of glass in the winter. I used propane heat, so I would just turn off the heat while I was laying it up, then if the fumes got too bad I would open up the door for some fresh air after it kicked off. You should be good with the electric heat, do you have any pilot lights or open flames? You might want to put them out if you are doing a lot of glassing. The fumes don't seem to be very volatile, but it never hurts to error on the side of caution!

Thanks Arch, were you using poly, vinyl or epoxy?

I think I may opt to seal the entrance door into the house with plastic window film when I glass. We have other entrances we can us in the interim. May help to keep out some of the fumes from the house. Someday maybe I'll get around to building my detached garage/workshop/man-cave...lol Someday, someday

 

[AMD Rules]

Well, many many months between updates... oops. It has been so long some people contacted me to see if I was still here
I have a question to ask, but figured I should update this thread first.

Not much has happened since then, but I have acquired a (used) factory fresh rebuilt powerhead and cowling, along with a few complete mid-sections etc. Just waiting for a couple of cowling mounting brackets, and I'll get that assembled and tested on the stand. Cowling is from a 135hp, the powerhead is a 1988 150hp V6

Also acquired a trailer for this boat. Its originally from a SeaRay manufactured by Midwest Ind. in Indiana, Model SRV24 circa 2007, should fit fine with a little tweaking. Has the hinge tongue so the plan will be for the boat to be a garage queen so to speak. Not sure yet if I will paint it or not. I like the corrosion resistance of galvanized, but not the appearance. Go figure both of my boat trailers are galvanized.

I'm about 60% complete grinding, so far so good. Expect to be completed grinding within the next couple of weeks and can finally move on to glassing in transom, stringers, and floor.

Onwards... itch itch itch

 

[AMD Rules]

I'm going to glass in the transom & stringers then put the cap on to be safe.

I finally put the hull on the trailer for the first time, seems to fit good. Trailer is a bit big for it, but I like it. Winch would work, but I'll re-position that later once I determine that the bunk angle is perfect for launching. Grinding is 90% done, I made it all the way to the transom area in the center, a ton of resin dust generated. Maybe an hour left of grind the hull left, yay.

Next on the to do list is lower the cap down to grind under the trasom/splashwell area and up under the rear spoilers. I think I have accepted the fact that I will cut out the back of the splashwell to make sure I don't have fitment headaches after the new transom goes in. I want to make sure that skin is eventually well bonded to the transom where the upper motor mounts are.
In my head, I have a stringer and bilge layout plan. I want additional transom support. When grinding the hull I exposed the chines next to the main stinger. Originally these were sealed cavities covered in a sloppy layer of cloth and (dry) cardboard only, but I think I will be adding two stringers to my hull. I've measured the motor mounts, and I believe these two stingers should fit either side. This will allow me to stop my main center stinger at the bilge area without fear of any strength compromise. All four stringers that meet the transom will slope upwards for additional transom support. I comprise on space for a fuel tank, but gain rigidity.

 

[AMD Rules]

The original hull had three stringers. One along the center keel, then one each on the outer strakes. I think I'll shorten the main stringer then use four additional stringers, all of which angle upwards to tie in the with transom and the under side of the splashwell where they can be.
Terrible sketch, but hopefully you can see my plan. Bilge will be deep, and I plan on relocating the drain to the bottom.
Floatation boxes will not be replaced, however I believe I will use foam under the floor for stiffening and dampening, not to mention increased safety.
My previous GT160 has a fuel tank up front. If I can find my notes, I think I will use the same style (inside the ski locker).

 

[AMD Rules]

I found a fiberglass supplier , and picked up I what I hope is the majority of the supplies I will need.
10gallons of laminating resin, 1 gallon of waxed resin, 25yd of 1708 stich mat and 25yd of csm
Variety of rollers, chip brushes and mixing/measuring stuff, acetone
Some gelcoat and 2-part foam
I almost opted for composite structure (Coosa) instead of wood for the rebuild, but decided instead to stick with my original plan due to the prohibitive cost.

 

[AMD Rules]

The weather was perfect last weekend so I persevered. Finally 99.9% done grinding the hull... hooray!
Black and decker grinder deserves an award for reliability under extreme conditions, as do my neighbors for putting up with the noise and the dust. I think the reason my grinder survived is that I gave it a break every half hour or so, and also frequently blew out the vent slots to get rid of as much resin dust as possible.

Hull is done, you can see I added a new hole (oops), that is the yellow gel coat showing through. Transom has a million holes in it already, so one more isn't a big deal, right?

 

[AMD Rules]

Transom template done.

I used both a layer of 1708 and CSM between the transom layers.

Clamped the transom together with screws, which I will remove later before glassing it into the hull.

I cut the bottom of the transom wood at an angle with a jig saw (chewed through 3 blades, but it made it) to match the transom angle at the hull. Belt sanded the edges, and using a router gave it a 1/2" radius on all sides except the top edge (both front and back. It sits well in the hull, with a small gap all around the perimeter so the wood will not contact the bottom of the hull directly once its bedded in place.

Temporarily pulled the transom tight with some screws to see how well the outer skin pulled up flush. Not sure yet if I will use a traditional flared brass drain tube, or notch out the transom wood to glass in a pvc tube on the inside and use an exterior mounted drain plug. Leaning towards the traditional method, as I will need to flare in a drain tube for the splashwell drain eventually.

 

[Sparkinator]

Great boat! We had one just like it when I was a kid. Love the original seats with the black and yellow checks. I'm really excited to see this project as it progresses.

We had a hopped up 135 Johnson on ours, and it would fly. That 150 could get scary.

 

[AMD Rules]

Pulled the temporary screws, filled the holes with thickened resin (cabosil). DA sanded the whole thing and coated with resin, allowing it to soak it. Added a layer of matt to the aft side and around the perimeter tonight.

Hull is outside. Forgot that I had glassed over the original drain, and woke up today to see it had about 3" of standing water in it. lol
Drilled a small 1/8" hole where the new drain will be, problem solved. :lol:

 

[AMD Rules]

Made some progress this weekend, transom is now installed and curing. Bedded with thickened resin (cabosil and 1/4" chopped strand). I used a layer of peel-ply between the plywood clamping plate and the outer transom skin, hopefully the cracks and voids turn out well. I think it turned out okay, but tomorrow I'll know for sure when I remove the clamps.

 

[AMD Rules]

Cut three stringers yesterday, used my router to make a lap joint in each to get them long enough. Haven't decided if I am adding two extra stingers into the strakes or not. Might be too much work for too little reward. I've had just about every power tool in use, plus my air DA sander. Much more fun than grinding fiberglass!

Today, rain was coming to I modified my hull stand to support the deck, and flipped the deck around 180 degrees in the garage. This should make it easier later to put the shoebox back together, plus I didn't want the hull to get wet in the weather.
Note: DON'T use ratchet straps to pull the deck up for storage. They work great for lifting it, but they suck when it comes time to lower it Use pulleys instead.

Still have to cut out the old splash well, what a mess it is.

 

[AMD Rules]

That brings this thread up to date. My current question is:

I was considering adding two additional stringers to the strakes that I ground out on either side of the center keel. They were originally covered with corrugated cardboard (dry) and glassed over. Would I be compromising any hull integrity by adding two partial stringers, say up to the area under the front seats back to the transom?
Goal is to have a rock solid floor and transom. Plan is to have the center keel stringer end short (making room for bilge and the new centered drain) then have small knees angling upwards on the other four stringers.

What thickness of plywood are most using for the flooring? Originally had 1/2", wondering if I should consider 5/8"?

 

[AMD Rules]

Great boat! We had one just like it when I was a kid. Love the original seats with the black and yellow checks. I'm really excited to see this project as it progresses.

We had a hopped up 135 Johnson on ours, and it would fly. That 150 could get scary.

Hey Sparky, sorry about that I was updating several posts in the thread and noticed you commented within. Was yours the yellow '72 as well? This is my second one, I never forgave myself for selling the first

I think the 150hp will be okay.

 

[archbuilder]

I don't think it would hurt to add some stringers, but you could accidently create a stress area. Was there an issue with the transom before?

I used 1/2" under mine, then foamed it. Its rock solid, doesn't even budge when my friend Matt gets in (6'-6' 300lbs)

 

[Corjen1]

Cool Boat...Good luck on the rebuild!!

 

[AMD Rules]

I don't think it would hurt to add some stringers, but you could accidently create a stress area. Was there an issue with the transom before?

I used 1/2" under mine, then foamed it. Its rock solid, doesn't even budge when my friend Matt gets in (6'-6' 300lbs)

Thanks. Transom rotted, ripped almost completely off with an old Merc 125 on it. I'm sure whatever I do will be better than what they originally did, and if well cared for should outlast me.

Regarding the strakes, I figure I have two options. Fill 'em in with reinforced resin and glass, or build two additional stringers to fill them in. Because I related the drain to the very bottom, I'd like to end the center stringer well short of the transom (it originally went all the way) which when coupled with two new stringers will make a nice bilge area I think.

I don't want to find out that a hull will too many stringers is actually a risk of over-stressing the hull. Perhaps they need some flex?

I'm planning on foam (no debate required) as I have already bought 2-part 2lb foam for under the floor. I think it will make the floor much more solid & quieter, not to mention the additional safety aspect. I'm not replacing the original foam in the aft corners (wanting more storage space), so the additional foam in the floor will compensate for that.

Thanks for the feedback all.

 

[AMD Rules]

Thanks for the advice. I think I will fill the strakes in, and cover them with glass, similar to the original. Having 5 stringers just seems too much for such a small hull.
I am struggling to decide what to do for the bilge configuration. I mocked up an idea tonight using some scrap wood to make what I think will be my final layout. Plan it to end the center stinger about 10" short of the transom (ending at the bilge pocket at reduced height not as shown), which will allow my center transom drain to have good access, and leave enough room for a pump. Bilge pocket is 10" x 10" square, and roughly 4" deep. I may or may not angle all four vertical pieces upwards at the transom for additional support.
Any concerns with what I show here for a design concept?

Here's my Walter White (Heisenberg) impression...

 

[Bob_VT]

Looking good. Great motivation for me to continue on my Sidewinder

 

[AMD Rules]

I tabbed and glassed the transom in earlier in the week. Decided I need a break from fiberglass, and assembled the powerhead onto the mid-section. I had to swap oout the mid-section for one of the spares which had the appropriate exhaust boot for the cowling. Took a while, but it went okay. Ran the motor for the first time on the stand, runs really bad but started right up. I need to review the basics air/fuel/spark because something is not right. It growls, surges, seems to have a misfire and a couple of times it seems to breath fire (literally) out the bottom of the mid-section. I'm thinking the base timing may be off. Only a run at idle, as a test.
I had a few different choices for the exhaust diffusers/tuner, and I chose the longer one. Its much longer than what was on the '85 150hp motor I had. How sensitive is a motor to that exhaust diffuser/tuner? Should I use the shorter one?
This motor sounds like it would eat me for breakfast!

Cut the transom off the cap today and removed the foam up under the aft end. I'd like to have as much space as possible back there when it is done, for storage.

Put my spare chrome wheels on the trailer, I think it looks better. Not sure if I wil be painting the trailer or not (probably). Hubs are in great shape, I cleaned them all out then re-greased & painted them. Had two studs that broke free so had to grind two nuts off, otherwise an easy task.

 

[Corjen1]

Looks good, keep up the good work...