Official 380 Thread

Correct, it was for a runabout.

I just hate to drill more holes below the waterline…

So I'm right to assume the platform you got was not for a 380DA?

I actually prefer the stainless support poles, as it greatly improves the load capability of the swim platform. Not a fan of cantilevering all that weight with a 10" wide strip of fiberglass
 
Actually no. A new swim platform, as @Chris-380 stated, is not going to match the original. Setting the labor aside, the materials are going to be a lot less than buying a new one and it will be better than new when I'm done. Rather than sitting watching the boob tube, I can work on this in the evenings, tuning out the day's irritations.

The original platform is a perfect base point, to build a "new" one. I'll cut out the stringers, backing plates and lower skin, remove the coring, to have just an upper skin and vertical lip that attaches to the transom. The 2x8 jig keeps the vertical lip in the correct curvature.

  • Then everything gets cleaned/sanded and a layer of 1708 goes down to ensure a good bonding surface.
  • 1/2" Coosa 20# coring goes down as a single piece, or as close to a single piece as possible.
  • 5 or 6 layers of 1708 fiberglass goes down over the coring.
  • The six 1/2" backing plates made of Coosa 26# get epoxied to the vertical lip.
  • 5-6 layers of 1708 are epoxied to the vertical lip as a continuous layer, covering the Coosa.
  • 4" strips of fiberglass mat get epoxied onto the coring in each of the six stringer locations.
  • Each of the six stringers is measured and cut from 1" Coosa 26#. The lower part of the triangle for each (which will not be bonded to the platform) is rounded off.
  • 5-6 layers of 1708 goes over each stringer triangle, cured and cut flush to the two bonding surfaces (one the horizontal and the other the vertical backing plate).
  • Each of the 6 stringers are epoxied in place using thickened epoxy.
  • 1708 cut into 4" strips is used to tab in each of the stringers on both sides, both horizontally and vertically.
Let everything sit for about a 3 days to cure.

Then start cleaning off any blush with soap and water, and then barrier coat the underside.
Paint later.
A note about bedding the Coosa atop an existing surface. I helped a friend some time ago to do something similar on a deck repair. First we found that sanding/grinding the surface that the Coosa was to be laid smooth and profile as best as possible to eliminate pockets and high spots was important.
Second, as you plan to lay in a bonding layer of glass sand/grind it also to get it flat as possible.
Lastly, make up a thickened epoxy to bed the Coosa using either chopped fiberglass or micro-spheres and trowel in that paste over your bonding layer. Bed the Coosa into the epoxy paste and evenly weigh it down with literally hundreds of pounds of weight distributed evenly. The paste should ooze from the sides and fill any cavities. The objective is to eliminate any air pockets that compromise the assembly strength.

Coosa is very stiff - it will not bend. So, to profile it around curves it needs to be kerf cut at around every 3/4-inch (the greater the bend radius the further spaced the kerf cuts). When bedding those pieces make sure to fill the kerf cuts get filled with thickened epoxy also.

You'll need about a hundred clamps......
 
A note about bedding the Coosa atop an existing surface. I helped a friend some time ago to do something similar on a deck repair. First we found that sanding/grinding the surface that the Coosa was to be laid smooth and profile as best as possible to eliminate pockets and high spots was important.
Second, as you plan to lay in a bonding layer of glass sand/grind it also to get it flat as possible.
Lastly, make up a thickened epoxy to bed the Coosa using either chopped fiberglass or micro-spheres and trowel in that paste over your bonding layer. Bed the Coosa into the epoxy paste and evenly weigh it down with literally hundreds of pounds of weight distributed evenly. The paste should ooze from the sides and fill any cavities. The objective is to eliminate any air pockets that compromise the assembly strength.

Coosa is very stiff - it will not bend. So, to profile it around curves it needs to be kerf cut at around every 3/4-inch (the greater the bend radius the further spaced the kerf cuts). When bedding those pieces make sure to fill the kerf cuts get filled with thickened epoxy also.

You'll need about a hundred clamps......

Thanks for posting. Now that I've ordered a new swim platform, no longer working in the horizontal plane.
However...
I am still working on the transom (vertical) which presents it's own challenges. Given the location, nobody is going to see the inside surface of the transom, so the finished surface doesn't have to be perfect. Of course my OCD will ensure it probably will look better than what the factory deemed acceptable.
Rather than the kerf cuts, I'm opting to go with two layers of 1/2" Coosa Bluewater 26, which will bend easy enough to take up the curvature of the transom. The width is 120", which is more than the 96" (8ft) sheet.

Transom Core removed.jpeg

Each of the two Coosa layers will be 2 pieces, with the longer pieces alternating on the port and starboard side, so the joints don't line up between layers.
As @ttmott described the epoxying process is pretty much the approach that will be used. Since the Coosa pieces will be vertical, that does present a clamping challenge. I really don't want to drill holes in the Coosa to use bolts to press the Coosa to the transom fiberglass. There are two vertical 2x4s that support the deck, so they will be handy. Will cut some 2x8s the width of the engine bay and anchor to the vertical 2x4s and the port and starboard sides of the engine bay.
I then use that bracing structure from which to apply pressure to the vertical boards.
Purchased 4 drywall lifts that are effectively a reverse clamp, to apply pressure.
 
Correct, it was for a runabout.

I just hate to drill more holes below the waterline…

Art from SwimPlatforms.com sent me the following images of the 380 version of the platform.
Noticed no stanchions under the platform. He stated the 380 version doesn't have them.
I'm assuming it's because the transom is reinforced.

DSCN8914.JPG DSCN8916.JPG DSCN8917.JPG DSCN8921.JPG
 
A note about bedding the Coosa atop an existing surface. I helped a friend some time ago to do something similar on a deck repair. First we found that sanding/grinding the surface that the Coosa was to be laid smooth and profile as best as possible to eliminate pockets and high spots was important.
Second, as you plan to lay in a bonding layer of glass sand/grind it also to get it flat as possible.
Lastly, make up a thickened epoxy to bed the Coosa using either chopped fiberglass or micro-spheres and trowel in that paste over your bonding layer. Bed the Coosa into the epoxy paste and evenly weigh it down with literally hundreds of pounds of weight distributed evenly. The paste should ooze from the sides and fill any cavities. The objective is to eliminate any air pockets that compromise the assembly strength.

Coosa is very stiff - it will not bend. So, to profile it around curves it needs to be kerf cut at around every 3/4-inch (the greater the bend radius the further spaced the kerf cuts). When bedding those pieces make sure to fill the kerf cuts get filled with thickened epoxy also.

You'll need about a hundred clamps......

@ttmott was going to pass on the kerfing but was not happy with the force required to get the 1/2" coosa to conform to the bend of the transom. Was going to take a LOT of force, with the potential for voids. So, took your advice and kerfed the 1/2" coosa board every 2" with the Dremel Ultra Saw and US500 4" wheel. Now the board just lays in nicely. Going to still clamp it with the reverse clamps (lifter jack).
Here are some pictures, showing the kerf cuts, the Dremel 4" Ultra saw and the coosa laying up against the transom. You can see two of the jacks that apply pressure to the coosa board against the transom as well as the vertical kerf cuts.

Forgot to leave the heater on in the engine bay, so it was too cold to apply the thickened epoxy yesterday. Maybe today.
IMG_0467.jpegIMG_0468.jpegIMG_0469.jpeg
 
I have a (new to me) 380 w/ twin CATS. In the process of doing projects to bring the boat to my expectations. Among the projects is installing a TV in the salon. The original was above the fridge but it was removed. Any suggestions for mounting a replacement would be greatly appreciated. Here are the questions;

- What size TV would work best all around?
- Best location? I've seen a TV mounted on the bulkhead just above the access to the aft cabin are.
- Even a brand recommendation would be good.
Thx in advance.
 
We have a 1989 380 Aft cabin that has full bridge enclosure and full aft deck enclosure. Front helm window is solid material. I was quoted $1,100 to just replace the window on the helm about 3 by 3.5 feet. The stainless steel structure is in excellent condition. Has anyone replaced the their bridge and aft enclosure? Looking for estimated cost. +/- 25% would be OK. We are in Anacortes. We go to Canada each summer could leave the boat there and get it done.
 
Installed my new full winter cover today, not too bad for making from another 380 and driving it 5+ hours away to install on mine
 

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Nice Chris, it pretty much covers the whole boat …….at least what’s not in the water:)
 
Asking if somebody can tell me where fuse(s) are for the CO monitors in the cabin?
Thanks in advance.
Tim
 
Possibly behind your main power panel. Most times they are hinged and with the removal of a couple of screws should open.
The panel in the salon or the one in the bilge?
 
A note about bedding the Coosa atop an existing surface. I helped a friend some time ago to do something similar on a deck repair. First we found that sanding/grinding the surface that the Coosa was to be laid smooth and profile as best as possible to eliminate pockets and high spots was important.
Second, as you plan to lay in a bonding layer of glass sand/grind it also to get it flat as possible.
Lastly, make up a thickened epoxy to bed the Coosa using either chopped fiberglass or micro-spheres and trowel in that paste over your bonding layer. Bed the Coosa into the epoxy paste and evenly weigh it down with literally hundreds of pounds of weight distributed evenly. The paste should ooze from the sides and fill any cavities. The objective is to eliminate any air pockets that compromise the assembly strength.

Coosa is very stiff - it will not bend. So, to profile it around curves it needs to be kerf cut at around every 3/4-inch (the greater the bend radius the further spaced the kerf cuts). When bedding those pieces make sure to fill the kerf cuts get filled with thickened epoxy also.

You'll need about a hundred clamps......

Not sure how this job could be done with the engines installed. I think I'm done with the fiberglassing of the inside of the transom. First, a layer of 1708 fiberglass, then two 3/4" layers of Coosa Bluewater 26 (marine fiberglass substitute). Added 4" wide fiberglass tape around the edges, to secure the new outer layer to the old surface. After that was a mayonnaise-thick paste of epoxy around the edges, to reduce the angle the 1708 would have to bend.

Then three layers of 1708 fiberglass with 5:1 epoxy. No way I could physically manage a single piece of 1708 126" wide, so broke up into four pieces placed with a slight overlap. Even then, it was very very messy. Think shaping clay with your bare hands. In this case I layered four disposable gloves per hand and kept a condiment bottle filled with acetone and shop towels handy.

Had to limit the size of the epoxy batches with the slow hardener. Almost cooked off one batch, even though it was in a full size paint tray and the temp in the engine bay was hovering just over 60degF. 25oz seemed to be the magic volume. The last two 1708 layers took three tubs. Then almost ran out of epoxy.

The weather has not cooperated with overnight temps below freezing. Found seedling heat mats that are waterproof. Taped two of them to the outside of the transom. Then covered with a layer of styrofoam board. The heat mats have a thermostat with a temp probe. Threaded the probes into the styrofoam, careful to keep it as far away from the underlying heat mat as possible. Over top of that wend a layer of bubble wrap insulation. The thermostats were set to 85 degF, which kept the interior transom surface temperature above 60degF, even with freezing temps outside.
Inside the engine bay (note the fuel tanks are not there), I used a 1500W oil filled electric heater. Luckily where I am in the boat yard, there are two electric circuits that I alone am using. This kept the interior of the engine bay in the low 60s when freezing outside.

Between each cured layer of fiberglass, I made sure to wash the surface with soapy water and a scrub brush, just in case there was any amine blush. Then the surfaces were sanded with 80 grit and cleaned with Total Boat dewaxer surface prep, not acetone.

Next will be paint (Rustoleum 9100). Did a LOT of research on what surface covering to use, including conversations with the suppliers. This one seemed to fit the bill for painting the entire engine bay white. There are a lot of options, this one fit my needs best. Was very much turned off by the Total Boat Total Bilge, it requires sanding between coats.

IMG_0499 copy.jpeg
 
I've been a fan of the Total Bilge and have used it a couple times without sanding between coats. However, you need to let it cure much longer than the recommended 8 hours IMHO. And it really needs several days to weeks to reach it full cured state. Once cured it is really tough stuff.

I have a qt of White Total Bilge that I purchased (I needed grey) Its yours if you pay shipping. You could experiment with it before proceeding.
 
The vent covers on the port and starboard sides (P/N 791749 VENT, PLAS GRILL 4" WHT), anyone replace them or the screen (P/N 1278902)?
I've got the port one off and plan on removing the starboard next, so I can get the starboard fuel fill out and replace the fuel fill hose.
 
The vent covers on the port and starboard sides (P/N 791749 VENT, PLAS GRILL 4" WHT), anyone replace them or the screen (P/N 1278902)?
I've got the port one off and plan on removing the starboard next, so I can get the starboard fuel fill out and replace the fuel fill hose.

I pulled the entire engine vent out when I replaced mine as getting the vent hose attached is the hard part. Where the vent attaches isn't very long, to the hose wants to slip off as you reassemble. If I were smart I would have replaced the vent hose with a new and longer section.
 

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