1970 Seafari conversion to CC

[Terry England]

afishin82,
You are going to think we are a bunch of cantankerous curmudgeons, raisin sand about you saw-zall'in the Seafari up. I was thinking today that there is just one name on the title and it is yours, so you need to do whatever you think is best for "afishin82".
This is like a Seacraft think tank here and Don Herman, the moderator and Denny, Gillie, Strick and others know all there is to know about brackets, hull extensions and the "Center of Buoyancy" (not gravity) how to get optimum performance out of the 20' hulls.
You are at the right place to learn how to save a bunch of steps, time and money learning things what has already been "learnt" by these folks and they are happy to share their own experiences, observations and knowledge with you.
You have an interesting project laid out in front of you and a lot of steps to go through before you are finished. Proceed carefully, ask questions, take heed and press on.
(and pleeeze take down those "before" pictures of that pretty little yeller Safari ASAP, so Denny don't have to lay awake at night - it's like the "Cat Juggler" in the movie The Jerk, for him. Very painful!)

[afishin82]

I am still undecided on cc or cuddy. I already own a 25 ft walkaround and want a smaller cc for the nicer days! I am not dead set on this hull but I do want a 20 ft seacraft. I would be willing to trade for a cc if someone has one layin around. I dont mind the extra work, dont like to think about extra costs. I still have the cap, windshield, and bowrail. If I dont get a cc trade I will be willing to sell this stuff.I really appreciate all this feedback so keep it coming.

[afishin82]

So would a layer of 1708 a layer of 1.5oz mat and some supports on the hull sides be good enoigh or does it need to be cored. I want to do it right no matter what it takes so point me in the right direction.

[afishin82]

Haha thanks alot terry and im glad I signed up for this website and I get where you guys are coming from. I want to end up with a boat I love and Is built the way I want It so all the feedback helps.

[NoBones]

Sad, sad, sad.....

FYI:
1970 20SF on Daytona CL right now for $650
Stringers have been replaced and raised....
Needs transom..

[Bushwacker]

Originally Posted by afishin82

So would a layer of 1708 a layer of 1.5oz mat and some supports on the hull sides be good enoigh or does it need to be cored. I want to do it right no matter what it takes so point me in the right direction.

1708 already contains mat (17 oz woven roving + 8 oz. mat), so you don't need additional mat which adds very little strength anyway. The main function of mat is that it holds a lot of resin, so it helps fill in the gaps that would otherwise exist between the coarser layers of woven roving, helping to bond roving layers together. You definitely need a core to get back at least SOME of the stiffness you lost by removing the cap and bulkhead! Check out billythekid's post "I must be punishing myself" to see how to add the core inside the hull sides. Not sure if 1 layer of 1708 over the core would be enough, but billy's done this before, so if you do whatever he did, I'm sure it'll be ok.

[afishin82]

Thanks bushwacker I have already read the entire thread.its pretty awesom! Gets me pumped up to get mine going!

[Bushwacker]

A final layer or two of mat on the inside would actually be good for cosmetic reasons. Polyester resin shrinks as it cures, so the mat helps prevent the weave of the relatively course roving from printing through the final layer, and would require less fairing and sanding to prep for painting. Per a brochure from 1979 attached below, Potter used 4 layers of mat, more than anybody, between the gel coat and first layer of roving to prevent print-through.

Balsa core is a good choice for coring the inside of a hull above the waterline. It bonds well because resin soaks into it better than foam, plus it has at least 6 times more shear strength than most foams. For more info on core materials, check out this article by Dave Pascoe: http://www.yachtsurvey.com/core_materials.htm

[gofastsandman]

Originally Posted by NoBones

Sad, sad, sad.....

FYI:
1970 20SF on Daytona CL right now for $650
Stringers have been replaced and raised....
Needs transom..

Easier way to go as well.

[FishStretcher]

Sandwich (foam or balsa) core is a great stiffener. But it really would be easier to start with a CC. I just got done playing with a lot of 1/2" divinycel H80. And 3/4" H80. It is great stuff, but an entire hull would be a lot of work. It works really well with 1708 DBM as far as I can tell. But I am burnt out doing bulkheads and hatch covers. I think I sent north of $2500 on foam, vinylester, glass and consumables (for my 25 footer). You would need similar amounts in terms of dollar value. And work every weekend it wasn't raining. I hear divorces are expensive, but I haven't gotten that far yet. I probably spent an extra $600-$800 recently on "date nights" to try to strike a balance there. Plus a trip to the opthamologist for fiberglass in the eye, and a few hundred in Ryobi and and glassing tools. Two respirators, extra organic vapor cartridges, maybe 8 boxes of nitrile gloves, two moon suits, 4 gallons of acetone, 20 squeegees, 36 2" wide chip brushes, a dozen paint roller trays, a half dozen heavy ( 4 mil) plastic drop cloths...

A CC really is cheaper. Especially if it has semi working electronics or controls. I probably have $3K in low-midrange Lowrance gear on the 25 and it still needs a real VHF and a better bilge system. Probably $1000 in ethanol proof tanks. It will need a few hundred in A1 fuel hose. Your 20 might be cheaper in this regard. It still needs anti siphon valves, ethanol proof line, squeeze bulbs, water separators, O/B controls and instruments, if you don't have them. And a T-top. Those aren't free.

And a 150 4 stroke is too heavy for a 20 , IMO. A 150 with an OK prop probably is worse than a 115 with an optimal prop for performance. And aluminum props are $100 each. That's a lot of guesses, and a few spares between a 115 and a 150 in terms of dollars. The 150 might have 3 MPH for cruise speed over a 115. The 115 will have better low end planing speed. With a F90 or an e-tec, you won't need tabs. I have never priced them, but between 400-600 bucks smells right. Plus 14 more holes in the transom. 4 per tab, 3 per cylinder. Times 2, plus switches, pumps, controls, fusing, wiring.

I can hang with some 25-26 foot makos in a chop with a F100 on a 20. With a 20 gallon tank.

Get a SF or Master Angler with a notch, I say.

If I had the money for a motor, I would try a 90 or 115 e-tec for the weight. But I have a $1000 4 stroke 100 hp with a 4 blade and fin, and 6 hp kicker. It was super cheap. Still too heavy. But I don't need trim tabs. And it floats with a holed hull the way I worked it over.