Question about permanent fuel tank installation in 65 Sunchief

[JimmySmackdown]

First off, I would like to personally thank all the great contributors here on the StarCraft owners forum whose advice, insight and pictures helped guide me while I was putting my boat back together. I learned a lot during the course of the project, and I'm continuing to seek guidance as I refine and tinker with my boat.

I have what I believe to be a 1965 or 1966 Sunchief. Before someone beats me up about how it got butchered/cut up/remodeled, I would like to say in my defense that it came to me in much worse condition. It had at least three previous (abusers) and I took possession in December of 2015. I wouldn't call the work I've doing to it restoration, I think a more fitting description would be remodeling or re-purposing. I did my best to put it back into good working order so that I could use it as a layout tender for open water duck hunting. The wide-open hull is what caught my eye first and the fact that it is nearly 22 feet long and 7 feet wide provided a sense of security when I'm plying the angry November waters of Lake Michigan and Green Bay.

I'm not 100% certain that it is a 65, but from looking at all the great pictures and reading a lot of discussions here I think I'm pretty close. If anyone can verify this, please let me know.

As many others have mentioned in various posts, I would like to move some weight forward to trim it out. The first seemingly logical step was to move both batteries forward. Heavy duty 2 ga wire was involved, but I had already run pvc pipe chase under the floor so it wasn't too bad of a project. I also moved the twin 12 gallon portable fuel tanks forward. This however, has resulted in taking up quite a lot of the floor space in the bow. I would like to explore the possibility of installing a fuel tank / cell below the deck. My issue is that I have seen very few Sunchief's with outboards and mine has three stringers as opposed to the two stringers in the inboard version. Has anyone else successfully installed a fuel tank in an outboard powered Sunchief with three stringers? Does anybody else have an outboard propelled Sunchief?

Thank you for any help you can offer.

p.s. My kids have nicknamed it "The Duck Destroyer" I have to get the name printed up on some marine vinyl before next duck season.

I'll continue to add more photos when I can

 

[JimmySmackdown]

Here are some additional photos of the process. It was a sometimes frustrating, but very rewarding project. I especially like the "getting to use it stage"

Pre-demo Mayhem



Deteriorated plywood side storage





View of cut out helm and bow decking



Nasty green carpeting gone. I thought I might actually be able to keep the decking. Boy was I wrong.



And why was this cut out? Answer to follow...



Original decking, lots of missing flotation foam



This is why the cut-out in the decking was made, there was a puncture in the hull at some point or another



Some kind of epoxy over the hull repair. Not working though.



View of inside of hull where repair was made. Looks welded, but not very pretty



Original decking which had another layer of treated over the top. Not bad for 50 years of use.



Original decking at bow. Barely holding together but again not bad for 50 years



Original flotation foam perhaps???



View of hull repair from the outside, not really sure what was going on here.



Decking pulled out, in the process of removing existing foam. New closed cell foam will be reinstalled



View of stern before power washing the hull



Yet another missing rivet



Power washed and ready to head to the glass bead blaster



Back from the blaster. Now the transom replacement process begins. Two gallons of Gluvit later and all interior floor rivets and seams have been double coated plus all wooden components are also double coated. Notice the constellation of transom holes? I can't believe it doesn't leak like a sieve!



More holes than aluminum



The effects of treated wood on an aluminum hull. Fortunately I was able to repair and coat all the pitting with Gluvit before installing the new transom



Side view during the transom replacement process



This is the transom I pulled out. A previous owner replaced the original 1 1/2 inch transom with two pieces of 1/2 inch and one 3/4 inch piece. That adds up to more than 1 1/2 inches of thickness which bent the splashwell tray and bowed the transom aluminum. It also forced them to flatten out the transom cap so it would "fit" the thicker piece. The motor was also an XL shaft (25 inches) so the motor was mounted 4 inches higher than normal. This caused a 1 1/2 inch bow in the transom due to the increased rotational torque of the motor. NOT GOOD.



My First Mate ready to hit the open water. Too bad the boat has a long way to go at this point.



Dreaming of a center console?



Marine grade 3/4 inch plywood over freshly installed close cell foam



Outside the paint shop ready for the first coat. I ended up removing and replacing the outer plywood transom stiffener because I didn't like how it fit or looked.



Sitting on FrankenTrailer ready for paint



Back from paint, on newer tandem trailer with new 15 hp kicker and 90 Merc from a donor boat. I installed a marine two way radio, portable fuel tank(s), controls, lighting, fuse panel. Almost ready for the water and not a moment too soon.



View from the front with new paint



Windshield and other hardware and fittings came from the 90 Merc donor boat. I tried to re-use as much as I could to keep the cost down.



RhinoLiner installed on the floor for added traction during inclement weather. It was a snap to apply



View from the bow of the finished interior



View from the stern of the finished interior. I had not moved the batteries and fuel to the bow at this point. I would find out after using it a few times that it was tail heavy



Motor controls



First splash on a gorgeous October day



Thats a lot of water. View of Lake Michigan during sea duck hunt



View of the Destroyer making a retrieve from the layout boat



April trip to local lake for newer Mercury break-in

 

[Watermann]

Wow lots of work you've done Wally! Looking good even with the mods. :thumb:

Belly tank in that era of Chief wouldn't be possible due to the lack of hull deadrise (V) with your 65 being more flat/rounded. To move the fuel forward would be the only option under an elevated bow deck.

As you can see with my 70 Chief the hull has a significant deadrise and I still had to elevate the base deck 1".

 

[Alumarine]

Very nice work.
I'm guessing the 2 boards across the bow are for duck destroying somehow?

 

[JimmySmackdown]

Thanks for the feedback fellas. I was hoping to fit a tank under there, but I think I secretly knew that it just wouldn't work with three stringers. I guess I could have a tank built 8 feet long 15 inches wide and 3 inches tall, but it wouldn't put the weight forward which is what I'm going for after all. I had a conversation with my friend the aluminum welder / fabricator and he suggested I mock up a cardboard bow wedge tank so see if it fits and then he'd put one together for me. Hopefully I get the model properly figured out before the meter starts running. I'd like to keep the front deck as low as possible, while still keeping most of the weight forward.

Marc C, the wooden rails in the bow of the boat is a cradle to hold the layout boat when trailering, or when I'm motoring out on the lake to set up for diving or sea ducks. So, yeah, its part of the destruction process. I'll try to include a photo of the layout on the cradle for more clarity. I take it off in the off season so that the boat looks sexier.

This is what I'm trying to get away from:



I started looking at putting in a deck over the portable 12 gallon tanks I currently have, but it would end up pretty high off the deck and a bit unsightly



Hopefully we can figure out a design which will fit into the bow area, extend back away from the bow about 35 or 40 inches and be about 8 inches tall. I can then build a deck over the top of it. I'm hoping for about 35-40 gallons of fuel capacity. I'll try and remember to post pictures of the process as I do it. I'm not the best at including all the steps, but at least it gives others a look at how to start it and the finished product.



I used the 90 last year, but was not impressed with how it handled this large of a boat and the loads I carry (and it wasnt reliable) so I kind of went overboard (no pun intended) and upgraded the motor a bit. The 90 was an 1987, the 175 is a 1996. It was a rebuilt motor from a mechanic in Janesville, WI. Top shelf work and highly recommended.



Hoisting it into position, it weighs about 390# approximately 100# more than the 90 but almost the same as the 150 XL I took off in the beginning.



Here she is all snuggled in. The 15 four stroke saved my bacon more than a few times with the unpredictability of the 90. We had the boat on Michigan and the only power we had was from the 15. I still managed 9mph fully loaded and only burned a few gallons all day. Nice fuel economy, but not capable of outrunning a storm.



I wasn't really fond of the Mercury Racing theme, so I read a lot about repainting and applying decals and went for it. Kind of a nightmare trying to paint in cold weather conditions. I was in a heated shop, but the paint alligatored three times before I got it right. It all came down to drying time. I waited over a month between coats

Stickers off



Sanding it down (for the 3rd time)



Finally completed



I had a little bit of trouble with the 175 at first, but AJ (my builder) went the extra mile to take care of me. We thought it was thermostats at first, but it ended up being a faulty poppet valve. The motor would idle all day long but the overheat horn would sound around 3000 rpm.

Pre-splash checklist and the break-in process continues. I'm about 4 hours into the 7 hour break-in process. Its time consuming but I should end up with a very capable and reliable motor.

 

[JimmySmackdown]

So, since a below deck tank is doubtful, I decided to investigate the possibility of a custom built tank to fit. A friend who is a skilled fabricator suggested that I begin by building my tank out of cardboard. This way I can test fit it and visualize / evaluate if it a viable solution. Boy, was that a great idea.

Empty pallette



Here is the first one I came up with. 54 inches wide x 44 inches long x 6 inches tall. Lots of math later, this calcs out to around 40 gallons. I would build a deck over this for protection and it would serve as a raised platform.



This version takes up less floor space, is two inches taller



Now we're maximizing floor space and moving weight forward. A little more technical and a lot more math to calculate volume, but if I'm going custom I might as well get what a really want.





Final version. Shorter, more compact, and still 40 gallons.



In the boat.




My next post will hopefully include some pictures of the tank being built. I'm getting the pieces from a local fabricating shop. Since the tank is smaller, the smaller pieces can come from "drops" or leftovers from larger projects. This helps keep the cost of materials down. I've got a sender, cap and filler neck, and hose barb ready to be installed as well.

 

[Watermann]

I would opt for the tank design that spread the weight out more. Don't forget to account for tank padding of neoprene at least 1/4" thick on each side and on the bottom of course and with a smaller footprint I would go 3/8" padding on the bottom.

 

[JimmySmackdown]

Thanks for the advice on padding the tank, especially when I put this much work into it. I left an inch and a half space on each side of the tank and there is a six inch gap between the tank and the bow. I already have the neoprene cut to fit and waiting to be installed. I strongly considered the broad flat tank design (enough to build a model out of cardboard) but since I'm only adding 16 gallons more to my previous fuel weight, and my boat was still too light up front, I figured that it still needed to be concentrated forward. Now I just need that tank stitched together! Since my fuel consumption is around 17gph at cruising speed, 40 gallons gives me range, plus a reserve. Just in case...

 

[Candutch]

The boats looks great, awesome open concept. I was looking at your tank mock ups and they didnt appear to be big enough to hold 40 gallons so i ran the numbers quick. Herw is what i figured for the two prism tanks. Your first mock up tank will hold almost 31 gallons and the second will hold 36.5. To figure out volume for a triangular prism just multiply the length of the base of the triangle x the height of the triangle then divide by 2, then multiply that figure by the height of the tank (44x48=2112?2=1056?8=8448 cu in which equals 36.57 us gallons).
As for you last tank I would have to look up how to do one like that.

 

[JimmySmackdown]

Thanks for the comment Rob, I used a number of formulas to come up with my volume numbers. All of my tank designs are trapezoidal, so this makes them triangles with their points clipped. The last two of my designs are actually called truncated frustums. Frustums are two triangles of differing size laid over the top of each other with the additional component of height. There are volume formulas for them as well, but I had to go a step further to figure out and subtract the "point". My final design comes out to 40 gallons which should be a good balance between floor space, weight, and capacity.

 

[Jcris]

I've just recently stumbled across this thread. I'm curious how the custom tank build is going. I assume this will be aluminum?
The rebuild work looks great though. Seems a very satisfying project. Especially with your "first mate" helping

 

[JimmySmackdown]

Thanks for the interest and question Jcris. I'm lucky to have such a good helper.

Yep, it will be fabricated from .125 aluminum. I finally got the pieces from my friend so it's assembly time! The fit of the pieces was a little off, but I blame that on my measurements and the cardboard. The next time I mock up a prototype, I'll take the additional step of transfering the dimensions (and pieces) onto underlayment or paneling to check the fit before ordering the aluminum. I thought my cardboard pieces fit really well together, but it was misleading. I think they flexed enough to look great, but didn't actually fit that well. My welder says it won't be any trouble getting them to fit them together though which is a relief. When I get it back, I'll post some pictures of the finished product.

 

[JimmySmackdown]

Here is the assembled tank. My welder did a great job. I lost an inch of height due to the fact that the fit of the pieces was off a bit but when I filled it to check for leaks and then emptied it into 5 gallon pails, the volume still came out to 38.75 gallons. That's close enough to 40 for me.

It took a while to fill it up and even longer to empty it.






The tank is sweating because of the cold water and high humidity, so it made it a little difficult to tell if there was a leak or if it was accumulated condensation. I ended up toweling it off, and there were no leaks at all.



Installed in the boat with padding underneath and at each side



Fuel sender installed and kickplate being installed for protection. I left some gaps along the side to allow for some air exchange in the tank compartment, or at least that's my excuse for not scribing the plywood as close as I could to the hull...




Top installed with aluminum framing underneath for support. I sealed all sides of the marine grade 3/4 plywood with primer and will topcoat with gray Herculiner for traction and durability. It has rained so much here this spring that getting a window of opportunity to paint is fleeting at best.



The last thing on the list is hook up the filler hose, mount the fill cap in the gunnel and fill 'er up. I can't wait to take it out and see the difference in performance.

 

[ezmobee]

Really great all around. The tank came out awesome. I think bow-ectomy needs some aluminum angle to look more finished/stock but that's it. Nice job!

 

[JimmySmackdown]

Thanks for the feedback ezmobee. I am very fortunate to be able to call these talented craftsmen my friends. This project would have been far too expensive if I had to pay more than beer wages or wasn't able to trade labor with them.

You're right, there are a few more finishing touches that will make this look more professional. Then next and hopefully final phase is putting on new steel fender to replace the sun damaged and broken plastic ones. As I dive into it, it I'll try to post photos.