# Aluminum jet sled skiff



## bob_esper (Jun 3, 2021)

Well, it's finally time to get started on another boat. As some of you remember I built a poling skiff last year but I ended up not using it enough to justify keeping it along with my current jet boat that I run on the local tailwaters for trout and bass. The skiff ended up in a really good home on the east coast.

This made me really look into what it would take to have one boat that could work for all of my fishing. I'm well aware that there is no one boat that can do everything perfectly, but it's a bunch of trade offs and compromises. Since I do 90% of my fishing in our shallow rocky rivers I knew that design priority #1 was building a rugged/nimble boat that can bounce off some rocks and not be any worse for wear. Since I would like to pole the boat a couple times a year I took a look at some different skiff designs to see if there was any way I could make the new boat pole easier than my current jet sled. My current boat would pole incredibly shallow, but with the steep rake at the front and completely flat bottom it was a rough wet ride and very noisy in any chop. I decided that I would make the new boat a mod V and give it a longer transition at the front and that these two things would hopefully help make it a better performing boat on the pole.

Here is a picture of my current boat. Runs the rivers quite well, but I would like to have a little more speed out of my next one. The current one has rounded chines which are not advantageous for jet speed and with a completely flat bottom with a tunnel which leads to some cavitation issues. I have to keep the tunnel due to bouncing gravel bars quite often, but I wanted to try and help the cavitation issue. Currently my boat will run 30mph with just me in it and 28 with someone else. I'm shooting for 30-32 with 2 guys/gear in the new boat.


















New boat will have a small delta pad along with reverse chines on the sides. I know this will cost me 1" of draft at rest but it should result in better handling and jet performance. Most of the delta pad will end up becoming the tunnel but the small wedge that's left in front of the tunnel should help disperse air and pull water up into the tunnel. Other than that the only real changes to layout is that i'm going from a 1760 with 24" sides down to a 16.5/56" with 22" sides. I'm also going from a 20 gallon tank up front down to a 12. I'm going to keep the same 80# riptide on the bow with the 9.5' rod trays. The 90/65 will also just be getting pulled and set on the new boat.



















After a 15 hour round trip to Slidell I made it home last night with the metal for the hull. I'm picking up trailer metal and UHMW sometime this week. Hopefully I'll get started on cutting metal this weekend. Plan is to have it completed in September.










I will of course be putting a removable poling platform on this one as well. I didn't see the need to add that to my basic CAD layout.


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## noeettica (Sep 23, 2007)

Sweet !


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## JC Designs (Apr 5, 2020)

Bob, give me a call tomorrow. I’ve set up quite a few jet boats and have a few things to run by you if you’d like, James (352)220-9631


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## woodduck (Oct 7, 2019)

Looking forward to seeing this build Bob! Give me a call if you're ever in NC and we'll get on some fish.


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## Hank (Jan 14, 2019)

Looks like a good plan Bob!


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## mattmass (May 15, 2020)

Cant wait to follow this thread!


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## bob_esper (Jun 3, 2021)

Got the metal off the trailer last night. You can see the delta pad/reverse chines. 
I think I'm going to be happy I knocked out part of the dividing wall between the big shop and this little office area. Working in the air conditioned side is gonna be a very nice change of pace this summer haha.


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## bob_esper (Jun 3, 2021)

JC Designs said:


> Bob, give me a call tomorrow. I’ve set up quite a few jet boats and have a few things to run by you if you’d like, James (352)220-9631


Will do! I'm always open to tips and tricks others have learned through their trial and error. One such thing is changing my designed transom angles. My current jet has a 17-18 degree transom which pushes my foot more vertical causing excess drag. Changing it from 17 all the way down to 13 to reduce the drag and hopefully increase speeds. .


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## BM_Barrelcooker (May 4, 2011)

You will like the reverse chine.

question : can you make a progressive tunnel that starts midways in the boat and gets wider and deeper as it goes back ? I saw a fiberglass design like that once on a prop setup and it fed water to the prop nicely and eliminated all cavitation giving the craft a significant nudge on the top end. 
I’ll see if I can find the details .


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## bob_esper (Jun 3, 2021)

BM_Barrelcooker said:


> You will like the reverse chine.
> 
> question : can you make a progressive tunnel that starts midways in the boat and gets wider and deeper as it goes back ? I saw a fiberglass design like that once on a prop setup and it fed water to the prop nicely and eliminated all cavitation giving the craft a significant nudge on the top end.
> I’ll see if I can find the details .


I think so too, really hoping they help me pick up 1-2 mph and help with the sliding a bit. As far as tunnel design I'm probably not going to venture too far from what outboard jets has in their recommendations. The way i sized the delta pad doesn't really let me vary a ton from my original plan. I did get some good advice from J.C though on some things he's found through the years with jet tunnels that i may be able to incorporate.


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## permitchaser (Aug 26, 2013)

@bob_esper your right you can’t have everything you want in just one boat. I like jets, been on them quite a bit in rivers around here. My question is how would it perform in saltwater. Yes aluminum is noisy but so are some fiberglass boats. But with the shallow draft and a jet the won’t hurt much grass I think it has a place


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## bob_esper (Jun 3, 2021)

@permitchaser 
I've had my current jet in the ocean twice, once in Port St Joe and once around Hopedale. Both times it was in quite windy situations. Never had a single issue with cavitation or any other jet related things you'd think of. My only problems were I had about a 25mph cruising speed and 15 mile trip one way to the fish lol. It was actually really nice for when we went to Hopedale because i had no idea where we were going and didn't have to worry about running aground or hitting anything as long it wasnt sticking out of the water. 
I'm hoping with the Mod V it'll help some with the hull slap. I'm also using longer UHMW on the new boat as well. On the old boat i used a 12' sheet so it was right at the water line at rest so any waves were hitting alot of the aluminum above it. The new boat will have a 14' long sheet so it'll be well above the water line. My thinking is that alone should help silence a little since it'll be smacking into solid plastic vs aluminum.


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## bob_esper (Jun 3, 2021)

Picked up my 3/8” UHMW sheeting today. Going to make this one tough hull. I have 1/4” on my current and have yet to do any real damage to it. Luckily it’s neutrally buoyant so the added weight won’t really add to my draft. Also snagged some of my trailer metal.


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## bob_esper (Jun 3, 2021)

Got a little bit of work done this weekend. Got the bottom cut out, pulled in, and tacked up. Was my first time doing a mod v so had a little bit of a learning curve, but it ended up nice in the end. very minimal gaps. Got my sides cut out and gunnel welded on. 
Keeping the bow rake as gentle as I can in hopes that it helps with the harsh slapping some and helps her hop up on pad a bit easier.


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## bob_esper (Jun 3, 2021)

Spent the afternoon framing her up. Nice to see her actually put together. Not the easiest thing to do solo.


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## bob_esper (Jun 3, 2021)

Gonna lay out the longitudal braces tomorrow and maybe get to chopping out the tunnel.


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## bob_esper (Jun 3, 2021)

Braces are fit. Now to fit the bulkheads and cut out the tunnel.


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## GoGataGo52__20 (Jun 26, 2016)

You make it look easy thou bud


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## Yako (Jan 7, 2019)

Following. Cool build


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## bob_esper (Jun 3, 2021)

GoGataGo52__20 said:


> You make it look easy thou bud


This build is alot more straight forward then the skiff I built so it's going together alot faster.


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## bob_esper (Jun 3, 2021)

Another weekend, another few hours in the shop. 
got the bulkheads cutout and fitted in place. Got the rod trays laid out and then did some slicing and dicing and got them in place as well. Now I just gotta notch out the tunnel and tack in the transom bracing and she will be ready for a few hours of welding.


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## GoGataGo52__20 (Jun 26, 2016)

Dang man, you make it look so easy


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## noeettica (Sep 23, 2007)

Amazing ! "Quality Aluminum" !


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## Smackdaddy53 (Dec 31, 2012)

Mighty fine work, love the tight fit joints.


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## bob_esper (Jun 3, 2021)

Thanks guys, Got my tunnel chopped out last night. I'm going to attempt and bend up a 1 piece tunnel on my pan brake. Also got a date for her planned completion - August 27th. We will be dragging it down to Port St Joe the weekend after.


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## bob_esper (Jun 3, 2021)

Spent an hour in between jobs last night and got the tunnel fit into place. I've still gotta add some gussets on the back side of the transom along with some bracing on the inside of the boat.


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## woodduck (Oct 7, 2019)

Looking good Bob! Can't wait to see the final product.


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## bob_esper (Jun 3, 2021)

Got some more bracing in place. If I smack a rock it'll most likely be in the last 2-3' of the boat so I wanted to make sure it was as beefy as possible. Going to be a pain when I go to layout the holes for the UHMW, but it ought to be stout when finished up. Still gotta add some heavy duty knee braces - probably going to use some 1/4 - 3/8 plate for that, but it'll be after I get the rest of her welded up. Going to weld up some of the longitudal runners and then flip the boat this weekend and TIG the seams up.


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## Natorade (6 mo ago)

Really awesome work!


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## C_Wheeler (Jan 14, 2014)

Just curious, what is the aluminum thickness?


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## bob_esper (Jun 3, 2021)

The outside portions of the hull are all 1/8" 5086. Decks and flooring will be .100 to try and cut down on weight.


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## bob_esper (Jun 3, 2021)

Got her flipped for the outside tig welding. Can get a good look at the bottom profile.


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## Hank (Jan 14, 2019)

Outstanding!
Keep up the great work.


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## bob_esper (Jun 3, 2021)

Got 1/2 or so of the seams welded up, got my tunnel gussets in place and my drain plugs welded up. They're tucked right above the gussets so I don't have to put them in from the inside of the boat to avoid them getting ripped out when I bounce bottom. Also got the horizontal welds burned in and ground down flush to smooth out water flow to the pump.


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## bob_esper (Jun 3, 2021)

Not any ground breaking progress in the last few nights. Finished up all the seams and started cutting/tucking in where the crimps will terminate. Gonna finish them up this evening and then flip the boat back over to weld out all the inside seams and runners. Hopefully starting UHMW this weekend.


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## AJ in Cali (6 mo ago)

If you’re in Cali, I’d gladly accept the job of apprentice? Are you taking applications lol. Awesome build Sir! I’m going to build on some day.


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## bob_esper (Jun 3, 2021)

Finished up the front end last night and got her flipped over. 1-2 nights of welding and then I get to start drilling/tapping 400 holes in the bottom of this thing. After that everything becomes really straight forward and easy though.


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## bob_esper (Jun 3, 2021)

Got all the runners welded out last night and most of the inside seams. Should be finishing those up tonight and then it's time to start tackling the UHMW. Went ahead and got her unrolled so she can flatten out nice before I have to start chopping into it.


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## bob_esper (Jun 3, 2021)

Big day tomorrow. Gonna start actually attaching the uhmw. Just gotta cut out a notch for the rake and tunnel and then she’s ready to start drilling. Had to make some mods to my saw to be able to track straighter, but other than that was pretty easy cutting it roughly to size. Laying out the grid pattern took about 2 hours by itself. Gotta dodge all the longitudal runners so I needs to be pretty accurate.


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## bob_esper (Jun 3, 2021)

Got the hard part of the UHMW done this weekend. I've left a good 1/2" all the way around so I can take a trim router bit to it and cut to fit later on once I finish the bolting. I purposely did not cover the last 3" or so of the tunnel because I will add a flap that fits snugly around the jet foot once I get the motor mounted and that will leave me room to bolt it on.
So far I'm very happy with how the UHMW has turned out, the adjustable countersink has been a huge help in getting an A+ result.


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## GoGataGo52__20 (Jun 26, 2016)

Sorry for my ignorance but what’s the UHMW for?


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## fishnpreacher (Jul 28, 2018)

Ultra high molecular weight polyethelene


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## fatman (Nov 23, 2012)

GoGataGo52__20 said:


> Sorry for my ignorance but what’s the UHMW for?


I'm gonna guess, just to see if I'm correct:
impact resistance + the ability to slide over rocks (AL can be "sticky")

what do I win?


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## bob_esper (Jun 3, 2021)

fatman said:


> I'm gonna guess, just to see if I'm correct:
> impact resistance + the ability to slide over rocks (AL can be "sticky")
> 
> what do I win?


You are correct lol, the river we run we have to run up some shoals about every mile or so. Most the time you can weave through them without issue. But a couple times a trip we have to bounce over a couple. The aluminum would probably hold up fairly well, but the UHMW just gives you alot more peace of mind. Plus when I drag it to the coast it will protect from oysters.


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## bob_esper (Jun 3, 2021)

Got alot of the UHMW done. I've still gotta go around and put an additional bolt between all the bolts on the outside perimeter.. but she's really starting to look like a river boat now. I'm hopeful she will also help quiet hull slap a little when poling. 
Tonight or tomorrow night i've also gotta silicone the seams to keep sand from getting under it.


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## stoked (7 mo ago)

Did you put nuts on the screws or just cut them flush


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## bob_esper (Jun 3, 2021)

The hull is tapped, but they also get a rubber bonded washer on them with a nylon locknut. Along with some anti-seize.


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## stoked (7 mo ago)

That’s the way to go. Some people that don’t have a floor cut them flush. I could never understand that.


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## bob_esper (Jun 3, 2021)

I had an airboat that the ones in the sides were like they. Barely stuck through. Never leaked though


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## bob_esper (Jun 3, 2021)

Finally all finished with putting holes in the boat. These will hopefully be the last pictures of her upside down haha. Also, my gauge panel came in. I had a company water jet it out of 1/8" aluminum. I still have to go over it with a surface finishing wheel to give it a brushed aluminum look, but it turned out pretty well. Its going to mount under my outboard like my current jet's panel does. I've really liked running my switches there, no chance of hitting them with your knees or anything like that.


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## bob_esper (Jun 3, 2021)

Got her flipped right side up again. Should be all done flipping her around finally. I did fill her up with 6” of water to check for leaks. I did the same with my current jet boat with uhmw. Once again,no leaks. Can never be too careful though after putting 500 holes in the bottom of a boat lol. Really loving the lines of this boat. She looks fast haha. Gonna be slow progress for then next few days, I gotta work on paying customers stuff for a bit so I can order my 450$ worth of turf for this thing.


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## GoGataGo52__20 (Jun 26, 2016)

I mean dude, you basically built a boat in a month, including getting materials from scratch. That’s pretty crazy fast


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## bob_esper (Jun 3, 2021)

GoGataGo52__20 said:


> I mean dude, you basically built a boat in a month, including getting materials from scratch. That’s pretty crazy fast


Thanks! I'm hoping she will be done in 2-2.5 weeks. Minus building the new trailer. I'm dragging her to Florida in right at a month.


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## GoGataGo52__20 (Jun 26, 2016)

Where r u gonna fish in Florida?


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## bob_esper (Jun 3, 2021)

We are headed down to Port St Joe for the week of Labor Day.


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## bob_esper (Jun 3, 2021)

Progress has slowed down quite a bit. Having to split my time between paying jobs and this thing. Should be back full bore by the end of this weekend though. I did get my front storage framed out yesterday. The big hatch is going to be primarily for accessing the fuel tank and batteries, the little one up front will be for stashing odds and ends up front if needed. I also got my knee braces fit up, figured it was easier to do it now vs after the rear deck is framed out. A few months ago i purchased a welder from an auction along with a random lot of aluminum. i finally figured out a use for this rolled material that came with it. I'm going to use it to make my livewell/baitwell sides. I've always heard fish do better with rounded tanks so figured it was worth the extra effort.


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## emilio19 (6 mo ago)

Dude that looks wicked!


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## 17hpxt89 (Aug 24, 2019)

Damn, what a battle wagon…… impressive work.


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## GoGataGo52__20 (Jun 26, 2016)

Yeah buddy


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## bob_esper (Jun 3, 2021)

Got my rear storage framed out. Gonna have a livewell, bilge area, and dry storage.


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## bob_esper (Jun 3, 2021)

Got my troller batteries mounted tonight, also ran the tubing that my anchor line will run through eventually. Going to use a cleat system on the front side of the bulk head. Hopefully if I really polish and round the edges the rope should hold up fine with the bends. I have an electric anchor system on the current boat, but I don’t use it but 1-2 times a trip tops. This will save me 300$ and 30 pounds or so off the front of the boat.


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## The Fin (Sep 28, 2021)

noeettica said:


> Amazing ! "Quality Aluminum" !


And no sawdust!😁


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## bob_esper (Jun 3, 2021)

Gas tank is built minus the full/vent. Waiting on tubing to show up. Should be right at 10.5 gallons. Typically I use 3-5 gallons on a trip. My current has an 18 and it’s way more than enough. Trying to save room/weight where I can on the new one.


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## devrep (Feb 22, 2009)

how do you keep salt water from getting trapped between the UHMW and the bottom of the hull and corroding the aluminum?


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## bob_esper (Jun 3, 2021)

Just a really good rinse is all I’ve done in the past. Lots of airboats run around in the salt and takes a long time to create issues. This thing only will see salt 1-2 times a year with lots of fresh water rinses in between. I wouldn’t do the uhmw on this boat if it were primarily going to see the salt. I’d just use a thicker bottom.


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## bob_esper (Jun 3, 2021)

Finished my flooring install last night. Went ahead and ran some PVC rigging tubes, one for fuel and one for electrical.
Time to start getting the decks covered now.


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## bob_esper (Jun 3, 2021)

Got the front and rear decks roughed out last night.I really tried to go big with my hatches on this boat.I'll also be adding a small pipe border on the inside edges of the deck overhang. . so it'll be nice and smooth and not a sharp corner to bump up against all the time. Crazy to think I should be rigging this boat out in less than 2 weeks now.


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## bob_esper (Jun 3, 2021)

Went ahead and got some of the rigging items out of the way. Mounted my fuel/water seperator, nav lights, and ran some wiring. Also went ahead and mounted some wire tie mounts under the decks so i can tie everything up nice and tight. Easier to do it now vs after the decking is on.


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## bob_esper (Jun 3, 2021)

Down in the single digits for days left before she's completed. Hoping to have all the metal work and the bulk of the rigging done in the next 7 days. Just gotta make my livewell and dry storage along with the hatches and then the bulk of the metal work will be done. Went ahead and mounted alot of my components under the back deck. Since i'd like to be able to do some more live bait fishing i went ahead and bought a bubbler, we will see how well it works.


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## bob_esper (Jun 3, 2021)

Got one of my storage compartments done. The livewell and dry storage will both be shaped like this with the rounded ends. I knew I wanted my livewell to have the rounded ends so it just made sense to make them the same. These inserts will drop right into one of the cutouts in the rear. Hopefully the rounded ends will be worthwhile since it's kinda a pain. I'll have right at a 20 gallon livewell and a 20 gallon dry storage.


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## bob_esper (Jun 3, 2021)

Got both my compartments welded out last night and set into place. Just gotta weld out the back deck and then she will be ready for some rigging.


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## bob_esper (Jun 3, 2021)

Got my gauges and weather stripping in this evening


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## GoGataGo52__20 (Jun 26, 2016)

Lookin clean!


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## bob_esper (Jun 3, 2021)

Putting the boys to work on the rigging!


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## bob_esper (Jun 3, 2021)

Well I couldn’t wait any longer. Got the electrical 75% of the way and the front deck turf done, but I had to take it to the lake that’s 7 minutes from the house. Super happy with how she did. 32.5 wide open with me and the whole family. 30 at 3/4 throttle. Handles waves much better than my old sled and handles more like a racecar Vs a 4x4. Hoping to pick up another .5-1.0 once I straighten my intake grates that are looking rough and fine tune how the foot interacts with the tunnel. But super pleased. My goal was 30 mph with a stretch target of 32. Beat both of them. I should only be adding another 25-30 pounds tops..


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## Smackdaddy53 (Dec 31, 2012)

Dude that’s not bad top speed at all for a 90 jet on that hull! Good job, she’s sitting pretty.


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## bob_esper (Jun 3, 2021)

Smackdaddy53 said:


> Dude that’s not bad top speed at all for a 90 jet on that hull! Good job, she’s sitting pretty.


Thanks. This boat is basically the same weight and almost same size as my last jet but she’s going 4-5 more mph faster. Just goes to show how much the specific design really effects the performance.


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## bob_esper (Jun 3, 2021)

Got all my electrical hooked up over the weekend and ran to the gauge/switch panel area. Just gotta wait on more waterproof heat shrink connectors to show up before I can finish it. Went ahead and bent up my front two hatches and turfed the front deck so I could mount the gas tank fill. After turfing 4 boats I think i'm finally starting to get decent at it lol. Found my biggest "oops" so far as well. My troller batteries barely fit into their spots. I used a normal starting battery that i had laying around when setting up their little nesting area. I guess my deep cycles are about 1/2" taller. One of them is a bit of a pain to fit in, but if that's my biggest issue I find i'll be golden.


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## Hank (Jan 14, 2019)

What a great boat you’ve made.


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## GoGataGo52__20 (Jun 26, 2016)

Sweet!


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## beabra (5 mo ago)

How deep and how long is the pocket tunnel? How close is the foot to the back on your transom?

Looks sweet.


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## bob_esper (Jun 3, 2021)

beabra said:


> How deep and how long is the pocket tunnel? How close is the foot to the back on your transom?
> 
> Looks sweet.


I basically followed the design on the outboard jets site. The foot completely tucks up in the tunnel. I've still got to add some skirts on the side of the tunnel to help force feed it while turning sharply though. I'm gonna try and do some tweaking today and then head back to the lake tomorrow and see if we can't hit a solid 33 loaded down. I think one of the best jet specific design things i did on this boat was the small delta pad and transom angle. Transom angle needs to be completely different than on a traditional outboard to get the most out of the jet.


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## beabra (5 mo ago)

Transom angle needs to be vertical or 12 to 15 degrees?


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## bob_esper (Jun 3, 2021)

More vertical than a propped transom. 12-15 for jets and I think 15-17 for props is the standard.


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## bob_esper (Jun 3, 2021)

Got my main flooring turf down last night. Made some more tweaks to my tunnel/jet foot. Going to see if we can't hit a solid 33 this evening.


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## bob_esper (Jun 3, 2021)

Got my front hatch hardware installed, mocked up my troller location, cut out and bent up my rear hatches, and added some side skirts onto the end of the tunnel to hopefully hold the water in while i'm doing donuts. . Going to take it out this evening and see how she does.


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## eberin (Jul 11, 2018)

Do you ever paint your sleds or keep it bare?


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## bob_esper (Jun 3, 2021)

I painted my last skiff, but typically I leave my aluminum boats bare.


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## bob_esper (Jun 3, 2021)

Went out for some more test/tuning. Lost 1 mph with my tunnel addition. I'm thinking its acting like a trim tab, so off she comes. We took a couple fishing poles though and trolled around for 5-10 minutes. Snagged our first fish in the boat. Nothing exciting or impressive, just a little white bass.


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## bob_esper (Jun 3, 2021)

Done some more speed tweaking. Fixed my tunnel where i thought it may have been acting like a trim tab. Still down 1mph from my first trip. I removed my intake fins after the first run as well. So back on they go. This time though instead of bolting some on the side of the intake i made some out of some 3/8" alumium and blended them into the intake as smoothly as I could. Overall they are the same size as the original, but MUCH MUCH more streamlined. Going to to go run her again this afternoon and see how she does. I've also got my poling platform framed out and 80% done, hopefully have it knocked out tomorrow evening.


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## bob_esper (Jun 3, 2021)

Took her out again last night and looks like I found that 1mph I lost haha. Back up to 32 and runs like a champ. Probably done tweaking on it until after we get back from Florida.


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## bob_esper (Jun 3, 2021)

Got my steps added onto the back of the boat. No more crawling into the boat after pushing off a gravel bar or clinging onto the motor for dear life when trying to get grass out of the intake. I went ahead and made my strap tie downs part of the steps as well. One less thing for the guy flyfishing in the back to hang on now.


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## GoGataGo52__20 (Jun 26, 2016)

Now that’s a good idea


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## bob_esper (Jun 3, 2021)

Got my poling platform in place. Going to be held on by stainless rivnuts so i can yank it off in a few minutes. 95% of this boats life it will not have the platform on. But I definitely wanted to be able to pole it when we go to the coast a couple times a year. Also bolted on my jet whale tail that I bought for my last boat. Going to go run it tomorrow and see how she acts with it on. Oh, and got my transducer slide mount on. This lets me pull my transducer up a few inches and lock it in place when I'm running the river.


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## woodduck (Oct 7, 2019)

Looking good Bob! Can't wait to see some shallow running pics.


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## bob_esper (Jun 3, 2021)

woodduck said:


> Looking good Bob! Can't wait to see some shallow running pics.


Thanks, Going to be running sand bars in less than a week lol. No clue when she will get on the river though. Hopefully in less than 2 weeks or so.


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## bob_esper (Jun 3, 2021)

Boat is pretty well finished. It poled surprisingly well. i think the UHMW really helps quiet the hull slap down. Don't mind the mess, we started out spin fishing since it was quite windy that day, but then we found some flooded grass to go poke around.


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## Nate38 (4 mo ago)

slick!


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## bob_esper (Jun 3, 2021)

Dragging her down to the Houma area Wednesday. Got a casting platform framed up. Gotta weld her up and cover it in turf.


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## bob_esper (Jun 3, 2021)

Started on the trailer for the boat over the weekend. I've been borrowing the trailer from my other boat to get my by for the last couple months. #3500 pound 4" drop axle, 3"x3"x3/16" tongue, nice and beefy. Nothing apart from the coupler is welded out. Since this is my first trailer i've ever built i'm trying to get everything tacked into place and make sure she's 100% right before burning too much wire into it. Fenders are just sitting on tires as of now.


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## bob_esper (Jun 3, 2021)

Trailer is almost ready to drag the boat on for a test fit and to set up all the guides. Other than everything being a bit heavy to move around solo it's gone quite smoothly. Alot easier than building a boat lol.


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## bob_esper (Jun 3, 2021)

After a quick acid bath today she will be ready for paint. So far I'm really happy with how she's turning out. I was really worried about getting all the spacing really tight for the boat sitting snugly between the fenders. I hate trailers that don't fit boats properly and with it being my first trailer build I spent quite a while working it out. It's going to be nice to have a HD trailer again, my last couple trailers were 2250# trailers holding a 1500# boat. Now i'll have a 3500# trailer holding the same boat and the axle will be the weakest point. I've drug the boat on and off this thing and it doesn't flex at all.


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## m32825 (Jun 29, 2018)

Nice work on the trailer. How did you cut out the tail light ovals?


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## bob_esper (Jun 3, 2021)

m32825 said:


> Nice work on the trailer. How did you cut out the tail light ovals?


2 holes with a hole saw and then just connected them with a sawzall.


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## nmcphail (Jul 17, 2009)

Bob,
What's your take on venting the tunnel? Doesn't do much for the small jet tunnel?

The tunnel I built into an alum mod-v boat is 4' long x 12" wide x 4-1/2" tall at the transom. In the calm, I can definitely feel it pulling the rear down, but hit a little ripple and it loosens up good, rpm's/speed both increase slightly. I've got the boat back apart and will be adding a vent to the front.

It seems some fiberglass mfg's have vented tunnels, and it's generally accepted as a beneficial addition to a tunnel... just good to get some dialog on the issue.


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## Smackdaddy53 (Dec 31, 2012)

nmcphail said:


> Bob,
> What's your take on venting the tunnel? Doesn't do much for the small jet tunnel?
> 
> The tunnel I built into an alum mod-v boat is 4' long x 12" wide x 4-1/2" tall at the transom. In the calm, I can definitely feel it pulling the rear down, but hit a little ripple and it loosens up good, rpm's/speed both increase slightly. I've got the boat back apart and will be adding a vent to the front.
> ...


I’ll butt in here. I’ve studied this a lot as well as shallow water skiff design and hydrodynamics because it’s what I do for a second job and will soon be my primary job. 
Venting a tunnel is a fickle process and is voodoo to most people. If you vent too little it won’t change much, if you vent too much the tunnel is basically like it’s not there. The reason a tunnel pulls the stern down is because the lifting action of the water pulling into the tunnel. The whole reason in having a tunnel is to get water higher up to your prop and water intakes. Venting a tunnel causes this suction to be lost by equalizing the pressure (think taking your finger off the top of a straw full of water) and the water flows straight past the tunnel like it’s not there. With the vented tunnels that have a ball valve you hop on plane with the vent closed and once on plane you can open the valve and lose the suction that slows a boat down. East Cape has a Youtube video illustrating this very well.
Bottom line is permanently venting a tunnel has to be done correctly or you might as well not even have a tunnel at all. New Water has a cool patented tunnel ventilation system called the Lamivent that is essentially a second chamber over the tunnel and the top of the tunnel has hundreds of tiny holes in it that only vent the tunnel at a certain speed because the suction caused by water moving into the tunnel hits a breakover point where it will start venting the negative pressure through the tiny holes. Basically a built in non mechanical relief valve.


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## bob_esper (Jun 3, 2021)

nmcphail said:


> Bob,
> What's your take on venting the tunnel? Doesn't do much for the small jet tunnel?
> 
> The tunnel I built into an alum mod-v boat is 4' long x 12" wide x 4-1/2" tall at the transom. In the calm, I can definitely feel it pulling the rear down, but hit a little ripple and it loosens up good, rpm's/speed both increase slightly. I've got the boat back apart and will be adding a vent to the front.
> ...


I did quite alot of searching and couldn't find anything that spoke positively about doing it for a jet tunnel. Part of the reason you speed up with a slight riffle is just the bottom of the boat in general loosing suction. This has been true for any boat i've owned.


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## nmcphail (Jul 17, 2009)

I'm guessing the smaller jet tunnel doesn't produce as much "downward pressure" as a larger prop tunnel, just because there's less water flowing through. The hydrodynamics part of all this is rather interesting.

I've seen the East Cape video, and I think the ball valve will probably allow a happy medium to be found/fine tuned.


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## bob_esper (Jun 3, 2021)

Painting is finished, now I'm just going to let her sit and fully cure for a few days before I start putting the bunks and lights back on it. I'm no painter, but it turned out pretty good and I learned a few more things. .If it doesnt hold up as well as I like i'll just have her blasted and galvanized next winter.


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## bob_esper (Jun 3, 2021)

Apart from safety chains and straps on the back the trailer is 100% finished. So far the paint is holding up fine and the boat will 95% of the time see freshwater only. I'm gonna go ahead and plan on stripping it next winter and having it galvanized though. Fits the boat like a glove.


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