'83 Sea Nymph SC-170 Full Restoration

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crazyeddie

Well-known member
Joined
Jan 22, 2009
Messages
47
Reaction score
36
Location
Fowlerville, Michigan
Hello all,

I just reclaimed my account after being absent since 2009. College, career, marriage, house, and two kids later, I finally returned to my love of boating with the massive project I'll be sharing here. Bear with me as I have almost 200 photos which I'll be sharing the best of and narrating as time permits. Hopefully this writeup gives people some ideas, inspiration, and encouragement for their builds.

Having fished out of an 11' rowboat most of our lives, my brother and I were on the lookout for a larger, more comfortable boat. Dropping over $35k on a new boat was not an option and 99% of the options on Marketplace and Craigslist were overpriced for the condition they were in so we waited. I ran into a friend of the family at the store one day and he asked if we knew anyone that was looking for a fishing boat as he had one for sale. We paid him a visit to check it out and found it was a Sea Nymph SC-170 Fish Tracker with a splashwell, livewell, running 85hp Suzuki DT-85, all on a tilt trailer. Our immediate observations were that it had been stored outside uncovered for years because it was butt ugly, the floor was redone in OSB that was swelled up under the carpet, the transom core appeared to be soft, and the hull was so heavy that two guys couldn't lift the tongue of the trailer leading us to believe the foam was waterlogged. Not knowing what we'd be in for, we drove away with it with registration in hand for $300 which we split.

The first thing we did was fire the motor. It was running on two cylinders and the fuel pump was sucking air from a crack in the fuel filter housing. The center plug was wet with water and that was dead giveaway that the head gasket was blown. The fuel/oil recirculation hoses and check valves were missing, half the skeg was broken off, the carbs were overflowing fuel from the vents, the rectifier was burnt, and it had the small 1/4" fuel line quick-disconnects for smaller outboards. That was just the tip of the iceberg on the motor.

We pulled the motor, mounted it to a stand, and popped the transom cap off to find the plywood core was basically mulch. My brother gutted the hull which included removing the carpet, console dash, OSB floor, a full pickup truck load of waterlogged foam, and the transom core which had to be excavated with a prybar. We found the outer aluminum transom skin was corroded through in a few spots but the rest of the hull and riveted construction was in good shape and not leaking.

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After plenty of power washing, scrubbing, and removing old hardware and fixtures, we looked at Coosa Board and marine plywood for the transom but my brother being the welder/machinist/fabricator opted to fabricate a transom out of aluminum tube that would outlast the rest of the boat. The original transom skin only had three holes corroded through that were big enough to fit the tip of a ballpoint pen through so he decided to straighten the original skin, remove the corrosion, paint it inside and out, and add a second aluminum skin bonded with marine sealer. With the aluminum transom core in place, new stainless hardware, U-bolts, motor mounting holes, and splashwell drain tubes were added. The hull was then rolled off the trailer, bodyworked, and prepped for paint.

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My side of the project on the motor was moving along. After breaking and extracting three head bolts, I verified the cylinders were in good condition for the age of the motor and replaced the head gasket. The carbs were stripped, cleaned in an ultrasonic tank, and assembled with new gaskets and needle/seat assemblies. I removed the original rectifier and wired in an aftermarket regulator/rectifier and new fuse holders that take ATC fuses instead of glass. I replaced the cracked fuel filter assembly and installed new fuel hoses, quick-connectors, oil injection hoses, and recirculation hoses and check valves. I removed the exhaust port cover, cleaned the water jackets out, replaced the impeller and wear plate, and installed a new thermostat. Repairing the skeg the right way was a task we weren't ready to deal with yet since we didn't know if the motor would even run well so we opted to install a SkegGuard over the broken skeg for the time being.

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After bodyworking and painting the outside of the hull we jerked it back on the trailer, mocked up the motor, and my brother started fitting the floor in 3/4" marine plywood.

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Originally the livewell doubled as the seat base for the captain's seat and a passenger seat. We thought that looked goofy and took up a lot of floor space so we relocated it to butt up to the front casting deck bulkhead next to the console. The lid was refabricated and split into two separate lids with Perko camlocks and hinged to the bow casting deck.

Hatches, seat pedestals, plates, and and DeckMate casting seats, captains seats, and rear bench seats got mocked up. The original console top (aluminum) and dash panel (plywood) were swiss cheese from years of different fish finders and added switches and gauges so they got scrapped and a one piece panel bent in aluminum.


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I'm not sure what this boat had in it for a fuel tank originally but when we got it, it had a portable 6/gal poly fuel tank tucked under the splashwell. Since we live in Michigan we're planning on hitting some big water someday and figured we better have some more fuel onboard. I bought a Moeller 23/gal poly tank with sending unit. We fabricated an aluminum angle frame and straps to attach the tank to the stringers.

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My brother and I are both married with little kids so we wanted to have our cake and eat it too, having a rear casting deck and seating for the kids so we decided on a bench seating arrangement that folds over and converts into a casting deck while also covering the fuel tank and leaving space for battery compartments on each side.

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We plumbed the livewell with a kit a kit from TBN that included the pump, FlowRite valve, hose, through-hulls, and pump-out aerator nozzle.

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Another view of the console and captain's chair.

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In between mocking stuff up, I played with the outboard for a while and found the trim pump motor had given up the ghost. Of course it has been long since discontinued from Suzuki but I found a complete Volvo pump that was a direct bolt-on for a good price.

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Hatches were added to the stern casting deck for access to the batteries and a screw-out inspection plate was added to the splashwell to access the bilge and livewell pumps.

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Next was the 8' 4-bow bimini top.

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Just kidding!! What year is that pickem up over yonder? 74?

Great work you and your brother have done. Nice and tidy.

And that's a helluva shop you have over there. Im jealous. lol (y)
The memes got me dying over here! Thank you sir.

I'm jealous too, this is my dad's shop / family hangout - my shop has a dirt floor. With all our tools and beer in one place and experience put together, there's not much we can't figure out.

The gray one is my dad's 1980 F100 stepside that's tubbed with nitrous and the blue '76 F150 in the back corner is my project. I have some pics of that one in my old threads from 2009.
 
The memes got me dying over here! Thank you sir.

I'm jealous too, this is my dad's shop / family hangout - my shop has a dirt floor. With all our tools and beer in one place and experience put together, there's not much we can't figure out.

The gray one is my dad's 1980 F100 stepside that's tubbed with nitrous and the blue '76 F150 in the back corner is my project. I have some pics of that one in my old threads from 2009.
LOL

Holy Moly. That '80 has gotta run like a scalded cat!!
 
In between interior paint and everything else going on, I started mounting hardware and lighting. I admittedly got stupid with LED lighting in this boat. I ran white LED compartment lights in all the hatches, under the console, in the splashwell, in the front of the bow for docking, an underwater transom light, a row of red LEDs in the gunnels for night fishing, a Firefly tall bow nav light for visibility over the trolling motor , and a Firefly telescoping 10' stern ligh to clear the bimini top. This was the first bit of LEDs.

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While my brother was spraying the interior, I prepped and sprayed the motor. We used epoxy primer and Rustoleum Topside topcoat thinned and sprayed with a Binks HVLP gun. You can see primer for the Tuffcoat rubberized textured paint we used next on the top of the gunnels.

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Some pics with the Tuffcoat applied to the tops of the gunnels and floor and black carpet glued in on the sides. The bow plate was stiffened up with a piece of 3/4" black nylon with the trolling motor quick attach base bolted through. It was a trick getting the fuel filler hose routed to the tank so my brother fabbed a housing for the filler neck in the splashwell bulkhead to give the filler hose a straight shot to the tank. The transom end caps and bow cap were polished and installed and I started running wiring to the motor through new rigging boots.

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Some shots of the interior coming together. The livewell originally had a rail on it to attach seats which we utilized for a rear facing seat. The seat can be removed and installed on another section of rail mounted to the rear casting deck when folded down for a forward facing seat for versatility. The Lowrance FS9 Elite fish finder and Motorguide Xi3 trolling motor are installed. We used a Millenium Mounts extendable mount for the FS9 for easy access from the bow casting seat and it will extend far enough to allow viewing maps and GPS from the console. Also seen is the gauge pod that my brother fabbed out of aluminum with a 3D printed bezel.

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Another shot of the gauge pod. Gauges are Faria Beede Euro black on black - 7k RPM tach, fuel level, and battery level. The three position toggle switch switches the battery level gauge between off (so it doesn't stay pegged when charging), the motor start battery, and the trolling motor batteries so you get a reading from them all. We used an onboard Battery Link charger from Blue Sea that charges the batteries on 110V and also functions as an ACR to split the charge from the stator/regulator to the two battery banks while on the water. The remote readout in the gauge pod gives a charge status indicator from the charger.

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Next we started adding switches and components to the console panel including a Humminbird depth sounder, bilge pump switch, livewell pump controller, FlowRite livewell valve remote, and Blue Sea Weatherdeck switch panel.

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The decals showed up from outboarddecals.com and I slid these on. Instead of keeping the original ugly beige and orange decal scheme on the motor, I went with the new late-90s decals and an extra Suzuki "S" decal on the back of the cowl.

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Some more LEDs added to the splashwell.

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Some docking lights added to the bow. Told you I went overboard on the LEDs.

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It took about two full days to get the wiring done including runs to the motor, console, and trolling motor. Almost everything I used with exception of the wire itself is made by Blue Sea including fuse blocks, battery trays, battery terminal mounted fuses, circuit breakers, and selector switches. The dual circuit master switch connects the motor to the start battery and accessory circuit to the console fuse panel to the trolling/accessory battery bank and also has the combine feature to connect all battery banks together for emergency starting of the motor if the start battery gets depleted. The other on/off/on master switch switches the console fuse panel to either the trolling/accessory battery bank or the start battery in the even that one bank gets depleted so you still have a means to run accessories. The toggle switch mounted to the fabricated aluminum bracket next to the master switches disconnects the charger's ACR circuit from ground to prevent the ACR from combining the batteries and draining them while in storage. The bilge pump, livewell pump, and fuel sender are connected to the main harness to the console with Deutsch connectors for easy removal.

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Some shots with the interior done showing the convertible rear bench seat and casting deck layout with the jump seat clipped in to the rear position then with the casting deck folded up exposing the bench seats.

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We took the boat out on it's maiden voyage, focusing on the expensive electronics we've had installed for months but never tested that were just about out of warranty. Naturally we found some bugs to work out with the fish finder, trolling motor, and outboard. The fish finder had to go back to Lowrance due to the power button being stuck depressed and cycling the power on and off repeatedly. The trolling motor was flashing a low battery power error light and anchor mode was jerky - this ended up being a wiring error on my part which I'll elaborate on later.

Some pics of the lighting on the water at dusk. It was encouraging to see something working properly that afternoon.

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The motor ran pretty good for a while. We didn't know it at the time but the previous owner had installed a new 21-pitch prop but it was from a 4-stroke Suzuki and the hub bushing was modified to fit and resulted in the prop loosening up due to it migrating on the hub rubber. We were able to hit 36MPH on GPS but at only 4200RPM, the AV plate on the motor was buried in the water, and it was a slug out of the hole.

We also had problems shifting into reverse that eventually resulted in total reverse clutch slippage. After tearing down the lower unit, we found the clutch dog cross-shaft was bent like a banana, broken in half, and all the clutch teeth on the gears and dog were rounded. All of these parts are discontinued so my brother, the fab man and machinist, TIG welded and machined every clutch tooth on the dog and gears. The cross-shaft was direct ship from Japan so I found an alternative hardened steel pin locally. The slop in the controller was very evident after making these repairs so we replaced the controller with a new Yamaha-style Suzuki controller. This solved all the shifting problems.

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To remedy the buried lower unit and get the RPM up to an acceptable range, I installed a 17-pitch prop and raised the motor several inches using a pair of CMC 2.5" setback brackets that we drilled to fit the motor and transom bolt patterns and clearanced for the transom cap. After these changes the AV plate is no longer buried and it still tops out at 36MPH but at 5000RPM and it's a rocket out of the hole. We might experiment with some different props and see if we can get some more MPH out of it.

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Lowrance sent us a new FS9 after the power button issue and it's been great so far. The trolling motor issue was caused by my wiring (or lack of). I used a SmartShore Trollbridge 24 for the trolling/accessory batteries. It's essentially a combiner that combines two batteries in series to provide 24V to the trolling motor but combines them in parallel for 12V charging. It switches automatically but we found that when we deployed the motor, the electronics were only getting 12V until the motor kicked on and triggered the unit to provide 24V. This was causing the low battery warning and erratic operation. We found there is a wire post on the top of the Trollbridge 24 that manually switches the unit to 24V mode when you supply 12V to it so we added another dual circuit master switch in the bow between the batteries and the trolling motor plug that connects the batteries to the motor and also connects a 12V wire run from the fuse panel to the Trollbridge 24 at the same time to force it into 24V mode. So basically when the switch is on, it's providing 24V with the batteries in series until you turn it off. You can see the switch in the bow panel below. Hopefully this helps someone else who is having the same issue.

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This is the mostly finished product and our first day at the lake with the families together taking their first rides in the boat. I'm working on getting some videos uploaded next.

Items on the agenda for this winter are rod holders, new control cables, and some tackle storage.

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Very nice !! You are fortunate to have skilled help availiable....my boat is similar to yours in size and layout. I found my bimini top to be to tall and act as a wind sail when underway. We are shorter folks at 5'6" so I lowered my top to just clear our heads when standing at the helm. Made a big difference on windy days....just some food for thought......enjoy seeing your pics, feel free to post more !
 

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