1978 20' Proline Classic Rebuild

[melba toast]

Now that the underside of the flange had cured, I started to add core to the flange to build up my floor level. I had a few areas along the old flange where the rotten floor had stressed the welds to the sides of the hull, and was delaminated. I did a quick little grind and cleanup of these weak spots. I used mill fiber putty to fill any holes and a little light skim coat to embed the foam. I also left the foam a 1/2" or so off the sides of the hull, with putty in joint. I did this just in case my cuts on the floor are no quite perfect down the road. Next step is to do another quick grind and clean up the putty... And then glass the upper side of the flange and core to the sides of the boat. I will probably use a matte/woven/matte, and or some biaxial, depending on what scraps are available. I am not glassing all the way to the top of the cap at this point. I will do that later, after my floor is in.



3/4" Foam for Flange





Starboard side embedded in putty





Port side embedded in putty

[dirtwheelsfl]

Man i wouldnt have puttied the whole topside of the foam like that. Alot of unnecessary work to do to clean it up for glass now. Id have left it bare foam and scraped off the excess that came out. Then when you tab it into the hull fill all the gaps and run a fillet and then tab it all wet on wet. Trying to save you some work!

[melba toast]

I didn't putty the top side much at all, only where I got a little messy back there towards the stern. It may look bumpy in places in the pic, but that is because I was using short strips of scrap foam. This is a flange, not finish work. I had the putty fired off pretty hot so I had to work fast. A little quick cleanup and grind and I will be ready to glass. I will have it prepped in 15 minutes, if that.

[melba toast]

So much for the 15 min clean up and grind! It took a little longer, but I am ready for the next step.

I got by the shop at lunch and spent about 45 mins cleaning up my somewhat sloppy mill fiber putty job, and prepped for the final layer of glass work on the top of the flange. We will put a layer of biaxial on the sides and the top of the flange and be done with it.

I also got some cool info on the boat, who from a guy that worked for pro-line for a number of years in the past:

1978 20 Pro-Line Sport
LOA 20'1"
Beam 7'8"
Hull draft 9" Flats boats, before they were called Flats Boats, we called them Grass Flats Boats, that Good Ole Dan, and his Dad built for the guides for the Crystal River grass flats, thu the "Pro" portion of the name.
Fuel 55 gal
Hull weight 1780
Cockpit area 80SF
Max HP 140

Test Report with a 115 Yamaha.
Weight as tested 2500 pounds
5700 RPM'S = 39.7 WOT
Secs to plane 4.4

Is my hull a true "Flatback" Proline ?

Yes, but not totally flat.
I think it was a 10 degree deadrise at the transom.
Pretty flat, but not totally.
I think the AquaSport was about the same.
 
This one was once a dual console, with twin 70's. I am rebuilding as a CC with a single 115 or 140. The fuel tank we took out was indeed 55 gallons, replacing with a 31 gallon to fit a new 4-stroke fuel economy. With composite stringers, divinyl cell floor, ect, the boat will be a good bit lighter. That old wet foam and wood was something!

I am guessing this hull will be a little rough riding, but has the shallow draft. I liked the compromise. I am hoping trim tabs and a 12" setback jackplate will help me out...

How wet of a ride is it ?

I've been offshore with that hull twenty miles and more many-many times.
It's a 10 degree deadrise at the transom. Pretty flat. It was designed for the Homosassa/Crystal river grass flats.
However, a good entry.
Sure, sloppy water, pretty rough ride. Pretty wet ride. Watch the weather and the water. That's what I always did.
I had a 24 as well with a zero degree at the transom, perfectly flat, and went offshore with it also.
Now, my offshore was Gulf side. Pensacola area. On the Atlantic side much less forgiving water.

There were alot of us that used them offshore.

You have to keep in mind what the hulls were originally designed and built for and that was the Crystal River area grass flats.

I never broke one.



All cleaned up




Other side

*Note: I did leave a little of the former wood in flange, where it was still solid. Its up high enough that it wont get wet. I plan to just wet it out with a little resin to seal it. This flange is really only semi-structural anyway. Its simply a guide for my new floor and stringer level, plus a little insurance where the floor meets the sides.

[melba toast]

From where I am at, its looking at next week as the begining of the stringer replacement.

Right now, I am thinking about 2" foam 2-4lb, placing four stringers in the exact position of the original design.



Because my new fuel tank is so narrow and lower profile, I may be able to run the inboard stringers continuously bow to stern, only building them lower to accomodate the new tank. I also plan to bulkhead around the tank cradle, to adding strength and functionality. One thing I am considering, is to add wings from the outboard stringer to the chine, like lilrichard did below.



However, I already have a layer of matte/woven/matte from the flange, and across the chine, and onto the floor. I am also adding a layer of biaxial matte from above the chine all the way across the floor to the inboard stringer. In fact, The whole boat is getting a layer of biaxial matte from above the chine, across the entire bottom. That is a lot of beef on top of the existing amount of glass which has held up with no issues for 30+ years. I also with have four stringers, vs two on most boats.

Is it overkill to add the "wings" ? I do plan to fill the entire outboard cavities with foam as well... Thoughts ?

[gran398]

Add the wings. She is opened up, its inexpensive, its good thinking, and you'll never have another chance.

Regarding the hull side "flange"...here's the good news.

In the past, most Aquasport and Proline rebuilders have, after demolition, left for rebuild two inches of glassed, moist/wet fiberglass encapsulated plywood floor/deck joined to the hullside, as a base to adhere the new deck. Part of the rebuild. If the two inch ledge was a bit wet... the thinking was to dig out the rot and inject with epoxy.

Nowadays..not looking the quick fix...looking  to preserve these hulls.

Glad you cut out the rot, and went new synthetic. Hope the next gen will follow...and go all synthetic on the longitudinal hull flange deck supports...closed cell glassed foam, or glassed nida, coosa, FRP, etc.

New on new, perfect. New on eventual rot...not so good.

Keep up the good work

[melba toast]

I got by a little late this morning. Got the upper portion of the flange finished. I cut and laid up a 5" strip of the 1808 Matte/Biaxial, followed by a slightly wider strip of 1.5oz matte. I actually tore the top edge of the last layer of matte to help with the finish work on the sides later. It took a gallon and half of resin, with 30 cc's of hardener in the first gallon, and 15 cc's in the half. I was working in 90 degree heat, but still got both sides of the boat laid and rolled out by myself before it kicked.

The flange is solid and will make a nice support for the edge of the floor. My new floor hieght will be almost 2" higher!

I took a lunch break to let the glass set. Then I cut the outside of the outboard stringer with a diamond blade. The port side was so rotten, the stringer just fell out! Nice and easy. I will have to use a prybar some on the starboard side.

Next, I continued to grind on the bottom. There was quite a bit of delaminated and resin starved woven to chew through. I am now about 45 minutes of grinding away from my next layer of glass.

I am going to lay a matte/biaxial/matte from above the chine to the inside of the remaining portion of the stringer. This will reinforce the bottom and the chine, plus make a nice surface to attach my stringers to.

I am going to glass my 2" foam stringers in one side at a time, one stringer at a time. No point in ripping out all the stringers, and then having the hull warp on me. All the old woven stringers will be removed as I work along... and will be replaced by multiple layers of 45/45 biaxial/matte, and a 0/90 layer thrown in as well.




Top edge of the matte torn to help with finish work later




Flange work complete, outside of stringer removed, more grinding work needed




Closer shot of the port side




Starboard Side Flange complete, more grinding and demo to do on this side

[seabob4]

Hey Melba, did you get that info from Mike C or from Tim?

[melba toast]

Mike C, very nice to get the hard to find specs from him...

There is no home for old proline projects, like there are for the aquasports and the makos. Glad to find a place here. There are some especially nice rebuild threads here, and some great advice also.

[gran398]

We're glad you're here, keep up the fine work.

[seabob4]

Mike C, very nice to get the hard to find specs from him...

There is no home for old proline projects, like there are for the aquasports and the makos. Glad to find a place here. There are some especially nice rebuild threads here, and some great advice also.

Mike is a walking encyclopedia of older PL specs, perf #'s, that sort of thing...and a really great guy, despite being a salesman!  

Proline was founded by the Attwood family, Dan, the Pres for a long time, still lives right at the west end of King's Bay in CR.  They did a lot of copying back in those days (circa 1968), but one thing I noticed in my time there was the, for lack of a better term, "wimpy" stringers on the older PL 22s and 24s.  We had a few come back to the plant for re-builds, and, I'll be honest with you, I looked at the stringers after the rotten floors were pulled out and thought...huh?  

So being that you have rebuilt the stringers and transom, she'll be more "Aquasportish" than she'll be "Prolineish"...which is a good thing!!

[melba toast]

It will be a little aquasportish in appearance also, when I get done with the cap  

[seabob4]

It will be a little aquasportish in appearance also, when I get done with the cap  

   

BTW, Old London Melba Toast is good with cream cheese...  

[Capt. Bob]

Dan, the Pres for a long time, still lives right at the west end of King's Bay in CR.  

Cutler Ridge?

[melba toast]

Mike with a nice red on a she dog...




One of ten on topwater, four trout also




Yes, they eat gulps, and we eat them !