1978 20ft Proline rebuild

[elite51203]

Change of plans...(1st of many I'm sure).

I was finally able to find some 6lb closed cell foam in 4x8 sheets to use for the stringers.  I ordered them locally today and should have them late tomorrow afternoon.  Kind of a relief since I originally wanted to go with foam, for a little more piece of mind.  And based on what I calculate, it will be the same price if not cheaper than using Aqua Tech ply.

[seabob4]

Did you get them from Composites One?

[elite51203]

Did you get them from Composites One?

I called Composites One, but they told me that they only distribute in bulk quantities....

I ended up asking Tommy at Hammerhead where he got his material for stringers.  He told me to try a place in Lakeland (Old Salt Marine).  They had what I was looking for, but they actually ended up getting it from thier sister store (?) Mini Craft in Wildwood.  I'm going to pick it up this evening, its about 10 minutes away.

[elite51203]

I got the boat down off the trailer. Should be easier to work in now. And I can do a little work on the trailer also.  

[elite51203]

Liner is out  

More grinding and prep work to do for stringers. The hull bottom is pretty flimsy without any type of stringer support.  As i walk inside the boat I can feel the bottom dip and flex...Im assuming that will strengthen up once I get a layer of 1708 across the entire bottom and get the stringers system in...

I plan on using the original deck tabbing/flange as a guide for the new deck.  I also plan on raising the floor at least 1.5 inches.

[CLM65]

Good looking, clean hull .  You are starting with a really good looking baseline there

[RickK]

ditto ^^

[melba toast]

The bottom is flimsy now, so make sure the bottom is well supported and level. You do not want to add additional glass until its flat underneath. Otherwise you will have hooks that you'll have a heckuva time filling later. I wish I would have done this on mine, and I did things one set of stringers at a time, thinking it would hold it together. It did somewhat, and I only have a small hook to fill, but its going to be a pain. You can even screw the bottom to some metal stock or some straight 2 x 4's, glass and then fill the small holes later - I would if I had it to do again. I did it on my hull sides and it really helped.

The additional layer of 1708 will stiffen things, but it won't be solid until you lay up the stringers. The floor needs to be well supported until then. Then it will be solid.

[elite51203]

Thanks for the advice Melba.

I will be sure to examine the bottom for a hook.

[seabob4]

Thanks for the advice Melba.

However, I'm still confused on what exactly a "hook" in the hull is?

Can someone help me understand please?

A "hook" most commonly occurs at the transom, where an unsuppoted transom actually sags in relation to the rest of the hull bottom.  This result in an unintended, permanent trim tab.  However, hooks can develop all along the hull bottom, more or less presenting a condition where the hull rises and falls.

Do some googling on hooks and rocker...

[elite51203]

Thanks for the advice Melba.

However, I'm still confused on what exactly a "hook" in the hull is?

Can someone help me understand please?

A "hook" most commonly occurs at the transom, where an unsuppoted transom actually sags in relation to the rest of the hull bottom.  This result in an unintended, permanent trim tab.  However, hooks can develop all along the hull bottom, more or less presenting a condition where the hull rises and falls.

Do some googling on hooks and rocker...

Thats exactly what I did seabob....gonna check my hull in the morning.

[elite51203]

Well I checked the hull for a hook. Very minor, approx 1/8 of an inch if anything.

Seems to me that's not even worth worrying about. What do you guys think?

[gran398]

Think what Melba was getting at is to do your best to prevent a hook. That is, stiffen her up before you start. The pros use chocks off the floor once she's blocked up. Looking at your last pic, you can easily duplicate that by running three horizontals beneath the hull, staub them to the ground...then go vertical with the side-to side hull supports.

As she sits, a one-eighths variance off the centerline is negligible.  Most seventies production boats had that brand new.

[elite51203]

I would like a little feed back on my transom....  I just want to make sure that it will be strong enough with the way I am building it.

The original outer skin has a layer of 1708 and I troweled on some epoxy thickened with cabosil.

I ended up using 4 layers of 1/2 inch aqua tech, with a layer of 1.5oz CSM and a layer of 1708 between each layer.  All of this combined will make it about 2 1/2 inches thick.  

I have 4 layers of 1708 on the inside of the transom, all increasingly overlapping the previous layer by at least 2-3 inches. I will also be adding knees from the new stringers.  It feels very solid.

Should I do anything further for any other structural support?

[RickK]

Sounds like it should be a tank Jay.
You lost me on the "outer skin has..." part though.  Is there only one layer of 1708 over the original glass of the transom?