1975 18' sf
 

My name is Dave and I live in Boca Raton, South Florida.
Been a member for a few months, mostly just reading and planning how to restore this 18' that needs a complete overhaul.
Not in a rush to finish this project, since I have other boats to use.
Recently finished redoing a 91 Contender and have an 18' Sea Hunt to fish from.
I got the bug to redo a boat and it's good for my mental health!

The demolition was mostly done on the hull when I got it, and I cutout the deck, liner, and cap. Plan is no liner, flush deck/ no step up box in front, raising the stringers and deck, raising the hull sides to keep the freeboard, make the cap one piece, and close the transom for now. Thinking about bracket/ hull extension.

I'm posting this on my IPhone, so can only upload one pic at a time.
Also put this build up on BBC, but pics won't load.

Here is how she looked when I started.

Here she is after cutting the deck out.

If you can see it, the transom skin is distorted. Ground down the gelcoat .

Taped over the holes with 6 oz. cloth.

Also cut out front cap and step up boxes; left some of the liner on the sides so hull doesn't splay out. Bow cap and stern boxes are detached, just laying on hull for now.

Ground out the inside of the transom and cut back the stringers to have more room to work and tab into.

Test fit of Aircell 24lb. high density foam.
Looks like close contact with outer skin; hopefull some mat, 1708, and putty will fill the gaps.
Also rounded top of core so glass will curve over it.

Filled in the holes on the skin with thickened epoxy.
Glassed in a layer of matt and 1708 on the skin and another layer of 1708 on the core. Thickened epoxy putty over the skin and around the core edges.
After setting the core in, screwed it together from the outside and then added a fillet and tab of 1708 on the inside.

Transom from outside.
Well that didn't work so well. Looks like lots of gaps.
I should have just cut off the skin and made a new one, but hey this is a learning experience!
Thankfully I got this boat cheap but between tools, materials, and screw ups it's adding up fast.
Already had to buy another 6 gal. of epoxy.

Ground most of the outer skin off; probably going to remove the rest too.

Debating whether to continue from the outside and tab Biax to tie the core to hull outsides, and finish with 1708, or go from the inside.

Will be easier to fair by going inside but I'll need to make a MDF board face/mold. And I might not be able to remove the core at this point.

Glassing to the outsides and under the hull and then fairing will be a pain.
But at this point I may have to continue this way.

Man that is looking great. How wet was the foam in the stringers? I see the foam exposed in the stern on back Stringer and didn't know how wet it may have been? Was there wood around the fish box thru hole on starboard side bow? Please keep us updated

Surprisingly the foam in the stringers, the wood deck, and the wood in the keelson are dry. Other than the transom, the rest of the boat looked solid, but the previous owner had already cut around the decks, caps, and all the under deck boxes.
Yes there was wood and beige color Potter putty around the front fish box drain and rear through hulls; they were in good condition. Had to use a hammer and chisel to knock off the putty; going to seal the holes and make new ones aft for the water intake and transducer.
I cut the stringers back, mainly to give me more room to work on the transom, but the foam was already exposed. There were some random holes in the stringers with open foam and some rusted nails.
Maybe someone prior tried to make some cheap fixes.
Also looked like some drier whitish color areas in the woven roving around the stringers; might be resin poor or from some damage to the laminate.

Good job and keep the pics coming!! I would like to see pics of the Contender. I love old bracketed ones.

X2

Link to my rebuild thread on THT: http://www.thehulltruth.com/boating-...contender.html

Pic of her back in water.

18 ft rebuild
 

Dave,

I am doing rebuild on same hull as yours. Intersting to see the top of stringers cut and foam exposed the same as mine. I found water in the very bottom of mine all the way forward to bow.

The gap between the top of stringers and bottom of the deck was between 3/4" and 1". I dug out all the old foam and raised the top of stringer so there was about a 1/8" gap between the new deck. I debated raising the deck 2" to make it self bailing. I'm 6'2" and decided not to because my knees did not feel comfortable above the gunnell.

I am going to run my wires from the motor to console using the existing channel on the starboard side. I forgot to measure the location of the opening next to the fuel tank well.
Will you do me a big favor and measure the length of the opening and the distance for outside of transom to aft end of the opening

thank you

Very nice! One of my favorites.

The opening length is about 24", tapers slightly top to bottom.

The distance from the aft end of the rigging channel opening to the inside of my transom is 71", so if it was finished with 1.5" core and the inner and outer skins, it would be about 73".

Dave,

Very nice. I also fish out of Boca and maybe see your boar getting splashed soon. I keep thinking about getting re-finished 18 or 20 but have not come across one yet. I fish 17 mako and get totally beat up every time I go out. 18 is a beautiful boat. Good luck with your re-build.

Gene

Gene, this SeaCraft may not be ready for a few years; it's a learning experience for me, so I'm taking my time to build it as I want to.
If I was in a hurry to fish it, I'd just raise the transom cutout to 25", put it back together as much as original as possible, and rig an old motor.
I like to fish offshore for swords and deep drop, so I'm sometimes over 20 miles out and 30 miles from home, so I'm thinking of making it a small, economical, but capable boat.
Thinking of the closed transom, which then requires some bracket or extension, the raised deck for self bailing, and then more freeboard, and the open layout, with a lot of under deck storage. A newer four stroke motor for the economy would be nice.
My Contender is great, but is bigger than I need, since I usually fish solo, and with fuel prices now, it runs about $200 to fish offshore for the day. And I usually go out 2-3/week, so it adds up.

Here's a pic of a swordfish I caught solo on the 18' SeaHunt last week. If the weather is good, the boat is capable, but it has a flat bottom and is not really built for the offshore fishing I do. With any seas, it pounds and it can take 2 hours to get to the grounds, plus you're beaten up by the end if the day.
I'm hoping the 18SF will be better suited.

You're welcome to fish with me sometime; we'll fish the bigger boat, the 18' Sea Hunt vs. your 17' Mako!

Dave,

I am sure it will be a great boat when you are done. I will keep an eye for your sea hunt, Last week and I went out of Boynton and we got a big king close to 50lb. Looks like they added some rock piles to prevent erosion and there is plenty of bait on those rocks. Keep posting your progress.


http://i791.photobucket.com/albums/y...ps01f279a2.jpg


Gene

Dave,

My 1st Seacraft was 23 ft and we fished it up to 50 miles off shore. The 18 ft boat has that same Seacraft feel in a head and following sea. I am really impressed with it, especially when you consider when it was designed.

Thank you for the dimensiions.

Ed

Dave

I'm enamoured by your project. I own a 77 sf 18ft
Let me ask you, is there any wood in the stringers at all or just foam filled glassed in boxes? I know that the floor is wood sandwiched fiberglass and I learned the keelson Is wood cored. Thank you.
David

No wood in the foam filled stringers; only wood I found below decks, is the Kelson and some small pieces where the through hulls were.
The stringers were a well thought out design, considering it was over 40 years ago, when most boat builders put in wood and set it on it's edge.

I fished on the 18' SeaHunt offshore yesterday, and comparing it to the open layout on the SeaCraft, I will have a lot more room on deck.
And hopefully ride better in the slop too.

I've only ridden in my buddy's renovated 20' SF a few times, and it was highly modified with a fiberglass bracket and 150 Etec.
I remember it rode and fished well but was very wet; we fished in some sporty seas with that little boat.
I would have bought it but they raised the deck and cut the shearline, so there was little freeboard. And he had numerous major problems with the Etec.

Transom is cutout.
Used a high speed disc cutter to get the slot started and Sawzall to cut through.
Came out clean and I didn't butcher the hull!
Now that the transom is out, have to add some 2x4s to hold the hull sides in.

What to do next- traditional 25" cutout transom or continue with the hull extension?
The extension is a lot more complicated, esp. to design a mold.

Laid the core back in at 5 degrees instead of the original 12 degrees to see how the bulkhead will look.
Prefer a more vertical bulkhead for more toe room and not to lean out when braced in the back.
Also this allows me to make the transom cap narrower.

Back to Home Depot tomorrow to look for mold supplies.

If you're hanging motor on transom, that shouldn't be a problem. However if you decide to install a bracket, just be aware that it will have to be a custom job, as most brackets are not built for the oddball 5 degree angle!

Thanks Bushwacker!
The 5 degrees is only for the bulkhead; if I make a bracket, where the motor mounts will stay at 12 degrees.

I read your post on Brackets-pro and con. And every other thread!
After owning and fishing a few cutout 25" transom boats. I would really feel safer with the full transom.
Since I'm redoing the whole boat anyway, I can move a lot of weight forward.

Do you think a hull extension will help with the Cog balance at speed, compared to a regular bracket, where the tub is raised up a few inches?

I'm thinking besides the static flotation, the extension will help lift the rear a bit while running.

I'm not so concerned with top speed, since most days I'm running in 2-3' chop.
So So the supposed speed benefit of the raised tub, isn't as much a factor for me.

Ah, that makes sense - thought it was strange that what I thought was transom core was so far forward of aft end of hull!

Amen brother! After making one return trip from the Bahamas in 6-8' following seas in my boat with a 20" transom cutout, I can relate to that!

Moving weight forward to maintain CG is the key to good performance with a bracket, especially on a smaller boat.

Regarding a hull extension, Carl Moesly's comment, when I asked him what he thought about the bracket on my boat, was "Why not just make the hull longer?!" So yes, a hull extension will not shift the CG like a bracket will. It will provide most of the benefits (except for WOT speed increase) of a bracket with none of the negative effects, so it's the best although most difficult/expensive option. Even with a maximum flotation bracket like a Hermco, the flotation tub will be out of the water when you're on plane, so that flotation goes away, causing a significant aft shift in CG.

Suggest you send a PM to Blue Heron, as he's thinking of making a hull extension for a 20 I/O CC model he bought a few months ago. He found a technical paper and some software from some folks at Stevens Institute, where they modeled and tested deep V hulls comparing baseline, bracketed, and extended hull configurations. The model predicted and hydrodynamic testing confirmed that the bracketed model runs with a higher trim angle (bow higher out of the water) and has a higher minimum planing speed than either the baseline or extended hull models. This explains the higher WOT speed for bracketed models, but it also implies a harder ride because the sharper sections of the V are not in the water at cruising speed. This theory and test data match my own experience, and is why I've been preaching in this post that, on a 20, you really need to avoid using a heavy 4-stroke motor on a bracket! Potter's arguments in favor of a bracket regarding safety and WOT speed/economy are correct AS FAR AS THEY GO, BUT THEY DON'T TELL THE WHOLE STORY! If you can't shift weight to maintain CG location with a bracket, I believe the modifications you will have to make to an get acceptably low min planing speed and soft ride at cruising speed will reduce prop efficiency and increase drag enough that you'd get BETTER CRUISE performance with the motor mounted on the transom!

I could not shift weight on my Seafari without making unacceptable mods to the boat, so even my DI 2-stroke motor is too heavy for use on a bracket. I had to add some band aids like a stern lifting 4B prop and a Doelfin to get my min planing speed and ride back to what it was with a 300 lb motor mounted on the transom. The 4B prop really helps you hang on plane down to 12 mph, but it has more blade drag so gets lower MPG and WOT speed than a good 3B prop. The Doelfin also produces lots of stern lift, but at the cost of extra drag, and my tests with the I-Command system, which calculates instantaneous MPG from a GPS spedo and fuel flow from engine computer, indicate that it costs me 0.1-0.2 mpg at cruise. I left it off for my recent 90 mile trip up to the Long Point gathering for that reason, since most of the trip was in the ICW where I didn't have to slow down to 12-15 mph to punch thru 2-3' square waves like I've often had to do on the Little Bahama Bank!

The bottom line is the benefits of the solid transom, big swim platform for diving, and extra room/storage in the boat provided by the bracket are big enough to me to justify a slight reduction in cruise performance, so I'd do it again, although I might consider using the ~50 lb lighter 125 hp "115" E-TEC that wasn't in production when I bought the 150. Optimum cruise on the 165 hp "150" is only about 35% throttle and it only needs 45% to climb on plane, so I'm convinced the "115" would still have adequate power but would burn about 30% less gas. However I've consistently averaged 4.4 mpg with the "150" on trips of 200-700 miles with heavy cruising loads, so I can't really squawk too much about fuel burn with the current configuration, considering that it has so much margin for even heavier loads if necessary!

Thanks for the reply!
That's why I think the hull extension is the best solution for me; just a lot more complicated.
I have limited space and equipment, so I need to make it with simple methods and tools.

I can make it in stages, such as making a simple, one piece transom first and then cutout the opening for the tub. But I'd have to glass the tub later- wet on dry.
To make it wet on wet, I'll have to make a more complicated mold, so I can do the layup at one time.

Right now I'm leaning towards making a one piece mold, about half the transom height, basically from the tub level down. It'll be more like a Euro Transom, where everything will be tied together.
Even the deck could be the integrated into the tub by extending it into the swim platform, if the heights work out.

Then I can make the bulkhead later, at whatever angle I want.
I could glass the bulkhead into the deck and sides, or make the bulkhead with an opening like a door or even wider, have the whole thing fold down, like a gate.

Some interesting possibilities!

Got some 1/2" MDF board and 1/4" Melamine panels, and 2x4s today, so after some grinding, I'll start playing with the layout.

Would be nice to cut some Formica faced 3/4" board and build a frame to hold the extension in place, but since I don't have a miter saw, I have to make the cuts by hand. The MDF board also doesn't have a smooth coating, so thinking of coating the mold insides with epoxy and then wax or wrapping the parts with packing tape.
Glassing is going to be the easy part.

My latest thoughts are to make an Euro transom, like on a 21 Contender.
I won't have to make a hull extension and can use the original transom line.

With the bulkhead set about 0 degrees and 12" ahead of the transom, I'll get a small swim platform, and actually have more room than the original 12 degree transom and cap.

I'll have to make a gate, so the motor can pivot all the way up, but this will make it easier to get to the swim platform or make a door, so I can slide big fish in.

With all the other modifications I've made, I will still have a lot more room overall.

With a traditional cutout transom, you need a wider cap, and a splashwell to keep the water out.
I could just make it a 25" cutout, but I've owned/ fished open transom boats, and don't like the water coming in.

So with the Euro transom, it'll keep the water out and it's simpler to make.

The amount of room I'll gain with the extension may not be worth all the work.

Any thoughts?

Sounds like an interesting project. Really interested in seeing how it turns out.

Great idea
 

Sounds awesome.
I can't wait to see the end result. Please keep us updated
Great talkin to you today.
Thanks for the knowledge

Not a lot new, but lots of rain and now wind- ruined my canopy.
Took me quite a few more hours, and grinding discs, to remove the rest of the epoxy and get down to clean glass.
Sanded it all down also.
Ground out small white areas in the original roving; looked like they weren't filled with enough resin in the original layup. You can see lighter areas near the transom. And some small voids near the strakes and outer chine.

After considering, cutout, bracket, euro, and even a shroud, decided that the extension was the way to go.

Cut both stringers forward about 24" to give
me at least 18" overlap for the layup.
Also had to remove foam from the starboard stringer due to an ants' nest that had drilled throughout.
Overall the stringers are in good shape other than some holes someone drilled in the tops.

Now to make/attach the forms, but weather is finally nice, so I'm going fishing next few days.

Another pic- all cleaned up.

Got the subframe built; used a 4x4, 2x4s, and a 5x4 sheet of Melamine board- it's set at 12 degrees.

Filled in some old thru hull holes, a strake, and cuts in the hull.
Beveled the glass back, laid some cloth on the outside and then thickened epoxy with cabosil and glass fibers and a bunch of 1708 layers on the inside. I'll go back over the outside spots when I do the exterior hull.
It's thick enough that I may put the seacock valve back at the same spot, esp. after the glass for the extension goes on.

After doing some testing, I'm concerned with the condition of the original woven roving; most of it seems dry and chalky white.
So to make some more work, I chiseled off much of the roving for about 24", to get some clean glass to bond to.
It came off fairly easily, compared to the leftover epoxy on the transom area.

What's a few more hours?
I hate grinding!

Glass cleaned up; I'm ready to finish the mold.
If only this rain would stop.

Mold almost done. Lots of carpentry work- almost fun!
All done with a cordless circle saw, straight edge, and angle finder.

Need to add keel section, cut off screws, and then do clay and wax.

Want to double check height of sides of tub. It's about 19" now, so should be right height, may need a bit more for the glass work.

With swim platform I'll be about 20" and I have 5-7" more for the motor mount lip.

I have a project 20 that I'm thinking of extending similar to what you're doing. My thinking at this point (at least one boat project away from starting on the 20) is this:

• Cut a piece of melamine board to match the outline of the transom.
• Turn the hull upside down and spray the aft 3' with PVA mold release.
• Spray the inner face of the melamine with PVA and screw it to the transom.
• Spray the aft 30" or so of the hull with tooling gelcoat and then lay up some mat and roving with some plywood stiffeners laid up in strategic locations. The layup will need to bond to the outer surface of the melamine board so it becomes the aft part of the mold.
• After cure, break it loose, flip the hull right side up, cut out the transom and prep like you've done.
• Then attach the mold so it extends behind the transom the desired amount.
• There's more detail, but you get the point.

For this to work, the steps in the hull have to be parallel all the way back. I haven't measured to confirm this, but they look to be. Not sure if this will be less work, or have better results than your approach, but it's what I was thinking of doing. More than one way to skin a cat...

Dave