68 AristoCraft 8-teen off and running

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

I thought that if I used pourable, how would the key hole be cut. I could not find a I/O example either.
The center pad of the transom thru which the outdrive attaches is 2" thick. The side pieces are less than that although I can not get an accurate measurement at this point.

The photo illustrates the center pad, the distance to the hull bottom. Ideas? Should the transom pad extend to the bottom of the hull? I believe I will use a good grade of ply with the correct epoxy and installation I have seen here.

 

[sphelps]

Re: 68 AristoCraft 8-teen off and running

Doesn't look like there's much to it . The pad that is . You could always call Seacast or Arjay and ask about pouring the i/o . I'm sure it's probably been done before . As far as the thickness goes you could build a jig to maintain a smaller than needed thickness then build it to within tolerance with glass . If you are planning on using epoxy resin for the build than you can rule out doing the seacast . Not sure on the Arjay's epoxy compatibility .
As far as the key hole . Make a plug or make the hole small enough to recut it out .
I'm sure it will turn out fine either way ya go with it .

 

[greenbush future]

Re: 68 AristoCraft 8-teen off and running

If you have the cap off, I cant see using the pour in stuff, it's just so much easier to build, shape and install wood just as it was originally. I bet it's much cheaper to do that way too. Considering you are adding some serious power to this thing, having a well tabbed in transom would only be better right?
I have never used the pour in stuff, but I have done 4-5 wood replacements on transoms, they really are easy with good access. Then you can tab in stringers, floor, all of it. You know why I'm watching this thread right Lt Dan.....?

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Yea I believe so., I spent the day rebuilding the sliding top. Replaced all the machine bolts, nuts, rivets and set the slide height, now it moves for & aft with ease, lines up perfectly with the windshield & when latched appears water spray tight.

I also pressure washed the grunge & black paint from the inner transom to get a clear picture of exactly why it appears to be three sections. And it dawned on me why, the stern is curved horizontally left to right its not flat. The center pad is 2"thick the wings are balsa & 1/2" thick with small 1" pads glassed in for tie down eyelets. So learn something new every day I suppose.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

I was explaining the transom curve situation to my Dad. My Dad is a retired fighter pilot who in his spare time has built several experimental airplanes using various materials, he explained how to measure and prep the wood for the correct fit using beveled cuts in specific areas of the transom without using steam or water to soften the wood forcing conformity to the outer skin. I will be traveling home next weekend to watch the master demonstrate a complex curve using simple bevel & radius cuts. I understand now why be blew up when we used his special "wing spar saws" to cut 2x4's for our tree house so many years ago I believe we ruined the blades on 4 tools.

I am researching another unique aspect of weaves & resins which may be easier to work with while offering unparalleled strength and waterproof characteristics. Again from my Dad and the aircraft industry. While I do not intend to pull 10 +/- g's in the boat if I'm correct the transom should have a 1/2 life of 250 years, tied into the stringers & motor mount box, strength issues will be answered. Thanks Pop!

 

[greenbush future]

Re: 68 AristoCraft 8-teen off and running

There are few curved transom replacement here, and it isn't that difficult, do a search, you will see the few methods, but getting it right isn't to tough.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Polished the bright work this day, will do the pexi this evening then I can remove the top, the windshield and begin sanding the remainder of the top side,

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Coming along rather nicely after sitting under the oak tree for 10 years. Once the top & windshield are removed then the cutting and sanding begin in earnest. I now have a CAD design for the stringers, fuel cell, engine mount structure (tied into the transom) & what type of transom wood I will use. Gonna be fun times on the bayou again.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Got up @ 5am, did the 1st pass on the Plexiglas before the sun & heat of the day, 2 steps more to go then UV protectant and sealant on the aluminum.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

As I said yesterday I removed the grunge & black paint from the transom to see what it looked like. How about any of you experienced transom replacers give me some advice. It looks to me that the "wings" to the center pad are balsa; this is my judgment looking into previously cut holes thru the transom. When looking through the key-hole it too appears to be a balsa core separated by fiberglass resin or sheets approx. 1/"16" thick. The center thickness measures 2"around the entire keyhole opening.

What would be the correct repair? An entire 2" thick transom? Less on the sides? I also think I need to drop the transom closer to the V in the hull and tie the motor mount stringers into the transom. I expect to place these stringers forward to the front and use them as the lateral bracing for the fuel cell as well as bracing for the floor which was supported by foam & 3/8" plywood. I decided to use 1/2"on the flooring going back, possibly 3/4". I'm not concerned with overkill strength on this one, but safety is important with the power going back in. So gentlemen, if you have the time and inclination, please advise me on what you think.

BTW, I received an e-mail that my software quarantined purported to be from AristoCraft, very official looking, basically stating to contact them immediately by reply about winning a major prize. Man I was thinking a new Torpedo would be sweet, so I called and spoke with them since my software spanked it, and they are known "good guys" and it was an attempt to "mine" information, AristoCraft is not currently giving away that beautiful Torpedo they have. Word to the wise.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Fit the bow navigation lens ( from AristoCraft) this morning minor cutting & leveling, don't like the lid or flag pole. The fixture is in rough shape cosmetically being pitted, can likely be re-chromed. I straightened the flag pole with body work tools, it needs chrome as well. Perhaps powder coating? I have to think about and look at it for a couple days.

 

[Scott Danforth]

Re: 68 AristoCraft 8-teen off and running

Lt. Dan. we are here to help, so do not insult the knowledge of most of the people here on the differences of automotive motors vs marine motors. Some of us actually know the chief engineers at Brunswick, Volvo, Indmar, Ilmor, PCM, and Seven Marine

if you want an LS motor, start with a marine LS motor. If you start with an automotive LS motor, it will fail. As stated, valve overlap and cam profile, gasket material, core plug material, pistons, fuel mapping, ECM's and operating RPM are all marine specific. Remember, unless its a racing boat, your RPM limit is governed by the outdrive oiling which is below 5500

Also, for the most part, Marine motors are speed density, not mass flow like your car.

Mercury and Volvo do not use automotive anything other than the injectors and throttle bodies. These are the common parts that go to the industrial engine division, not the automotive division. They do use MEFI or their own proprietary controller, not the Automotive controller.

you will need to keep the fuel pump cool to prevent vapor lock, which is why all the marinizers use a fuel cell comprising of a fuel pump, filter, and fuel cooler

Marine LS motors are all heat exchanger cooled to keep the motor from corroding

 

[Scott Danforth]

Re: 68 AristoCraft 8-teen off and running

Who has knowledge or experience with a ceramic pourable compound used to replace transom wood by a company out of Florida,
ARJAY Performance Products? I came across this while researching "composite transom material". The weight is purported to be 40-50% less than the comparable sealed wood/glass setup but many times stronger and will never rot, can be drilled & tapped for hardware.
Found the concept interesting, a pourable transom that works for the life of the boat.

Seacast is out of florida. it is basically 1 gallon of resin, one gallon of bondo, and a bunch of ground up boat hull chunks that you mix up in a bucket. they actually provide you the bondo brand creme hardner.

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

Hi Scott, thanks for the input. As to the knowledge insulting, not happening from me. My assumption was both Mercury & Volvo and others use automotive long blocks for their marine engines (Oldsmobile rings a bell), as does Yamaha, OMC and a host of others, and for many, many years, speaking only in terms of I/O power plants, I know nothing of outboards. Is this not correct?
I know cam timing differs, certainly rotation at times differs, incidental items like plugs in the water jackets, gasket materials and the like, baffles in the oil pans, placement of the oil pickup, I get all this. Here is what I do know. The basic block and heads from a automotive LS, modified for marine use, are significantly less expensive than the same item stamped marine.

By purchasing a LS1 or LS2 from a vehicle, ( the majority being sold currently with the ECM, full uncut harness, all accessories including the transmission either 6 speed Richmond Gear, or L460E automatic in the $3000-$4000 range, I can lay down (automotive term) all the things that do not go on my boat for nearly as much as the total purchase price of the powertrain thereby making my LS1 or LS2 FREE or nearly so! I have 2 standing offers for the 6 speed @ $2,500. That is the reasoning behind the automotive purchase. I have already researched the cam profile with the cam maker that grinds our GT, GT2 & GT3 BMW M3 cams for our competition cars, he told me no problem.
As for outdrives, I have a Bravo 1, (another buddy donated it for the project) if I use the LS2 (more plentiful) the engine produces stock the max HP limit for the Bravo 1, so I move up to an XR outdrive. That's the way projects go.

I like to cruise and quietly, to that end & built my way, I will be able to achieve 60mph @ 3500 rpm, using a 27 pitch prop, 1.36:1 Bravo 1, with .088 prop slippage. This is acceptable for me after all not much chance doing this speed on a river and why would you want to? You would miss all the nature but crossing the lake is another matter all together, 60mph is a stable, safe cruising speed for a boat hull this well built.

So there you have it, don't feel you need to pick the gauntlet up for the others here, I was not insulting them rather I was thinking aloud & I am certain if they have a problem with what I have stated, they would say something to me...like you did.

BTW, I passed on the pourable transom repair, just not for me and this project, I want solid known safety for this project, it's all about the LS series engine, great power to weight ratio and the next up & coming marine power plant.

Regards,

Doug

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

I do believe I'll make the cover I want, I like it better, composite & shallow.

Now if I can find the carbon fiber roll, :facepalm:

 

[greenbush future]

Re: 68 AristoCraft 8-teen off and running

That transom has some very interesting exterior curves too it, it not only has a bend from top to bottom, but from side to side as well. It looks really sexy from the back with the round air vents out the top, but the replacing of that transom looks like it could be a challenge. Lt Dan does the transom core have these same bends on the inside of the boat or is this just filled voids to give you a flat mate at the outdrive area? I can see the square pad that is flat to meet the outdrive flush, but whats the construction on either side of that where these curves are at?
I looked at a 19 footer last weekend and that transom scared me thinking I would be either steaming thin sheets of plywood to match this double curve, or some other method, the one I looked at, transom was mulch from past holes drilled, and leaking around the outdrive. Other than that it was a nice unmolested boat, 1974 model with 140 HP/Merc.

 

[Woodonglass]

Re: 68 AristoCraft 8-teen off and running

When you use 2" end Grain Balsa core to make hulls and transoms you can get very creative with your design. It's also amazing at how strong it is. Vacuum bagging and resin induction really strengthens the laminate. Hard for the DIY'er to replicate though!!!

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

It's certainly a compound curve. My guess is the inner structure is three pieces as a result. Looking at the photo you can see the three sections do not go all the up or all the way down. The center (keyhole) while being balsa cored is 2" thick stops short of the bottom of the bilge by inches, the drain you see I cut. When I looked from the outside thru a 1.5" hole that was drilled for a fish finder cable then packed with silicone sealant the balsa core is maybe 3/8 to 7/16 thick. My Dad says it's not a problem, he'll show me how to use bevel cuts to force the wood into position. That said he's not re-inventing the transom, the keyhole and wings will be marine plywood but likely not the same thickness. There appear to be plenty of holes in the transom to snug the new wood tight against the transom skin but if more are necessary, I'll fill them later.
I worked for and engineering firm in the 70's that built blast deflectors & aircraft engine test facilities. There is an epoxy we used that would anchor the deflector structure into the cement via 1" deadbolts; after curing 24 hours the resulting structure withstood an F4E running one of the J79's in full burner, this is the epoxy I am attempting to get, it is waterproof, has about 1 hour working time @ 75 degrees and will outlast the boat, transom and marine plywood. Don't know if I can still get it, I'm trying.

I like the 19, I bought the 18 based on it's limited production and oddly enough the not quite so flat transom ( now I'm laughing). I spoke with Bill @ AristoCraft the other day about a few things and was told that A) the 19 top will fit the 18 (The 19 top is much cleaner in my opinion. B) The glass will fit as well so while there are differences, there are surprising similarities as well. If this project turns out well, I'm planning on doing the same thing to a 19 if I can find a 165hp model as the engine cover is easier to work with. I understand the seats are wider, there is a dash with glove box, just a bunch of little things I like and the transom design is growing on me.
I'm looking forward to hitting the water I truly believe the boat will ride super.

Regards

Doug

 

[Lt. Dan]

Re: 68 AristoCraft 8-teen off and running

I understand that Wood. I'll be better off with the traditional repair I have studied here. My wife votes for the bag...the garbage bag.

 

[Woodonglass]

Re: 68 AristoCraft 8-teen off and running

Yup, I wasn't implying that you attempt to do the balsa core. If you were, I'd prolly discourage it. Again NOT an easy thing in a DIY situation. What you DAD is indicating with making beveled cuts, I've done many times in my woodworking experiences along with kerfing etc... to make wood conform to various shapes. They all work well and have their places. When resin is applied it will cure into a strong homogenous unit that'll last for decades.