Help me build a Sniper 45"

[RaceMechaniX]

Mine came with rails installed although I ended up extending the front portion to pick-up the motor mounts. 6" offset rudder.

[kevinpratt823]

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Did a little each day this week. Glassed in the transom with combo mat/cloth then patched in the edges with scraps of mat, glassed the hatch with mat, laid in the carbon kevlar, and built up the bridge over the top in front of the hatch with a layer of mat/cloth combo that rolls all the way down to the beginning of the V, really stiffened the area up and gave a ton of support. The rails are just for testing and fitting, I will match what I have to 1/4 birch lam plywood and install those next....... Also, as the carbon shifted and only made it up past the seam on one side, I ran a strip of cloth down the seam on the other side.

[keithbradley]

I use isopropyl alcohol to thin my epoxy. It was recommend by one of my supplier tech adviser as a good way to thin epoxy for a thinner viscosity.

If used for structural purposes, you shouldn't add alcohol to epoxy resin. It will significantly diminish the strength of the epoxy.

OP, are you using this epoxy resin in cool temperatures? Z-poxy finishing resin isn't that thick (for small bottle type epoxy) and certainly shouldn't be giving you issues with wetting out cloth. Make sure you are not in a cold environment when using the resin, and heat each bottle to around 100F-105F before mixing (can be done by placing bottles in warm water). Heat will thin the mixture substantially but also causes it to cure faster so beware of a shorter pot life.

[kevinpratt823]

If used for structural purposes, you shouldn't add alcohol to epoxy resin. It will significantly diminish the strength of the epoxy.

OP, are you using this epoxy resin in cool temperatures? Z-poxy finishing resin isn't that thick (for small bottle type epoxy) and certainly shouldn't be giving you issues with wetting out cloth. Make sure you are not in a cold environment when using the resin, and heat each bottle to around 100F-105F before mixing (can be done by placing bottles in warm water). Heat will thin the mixture substantially but also causes it to cure faster so beware of a shorter pot life.

I only used the Z-Poxy in the hatch, then I bought some fiberglass resin from West marine(not the west system) that uses the methyl ethyl keytone hardener, and it mixes much thinner and easier to work with. The temp is prob low 60's in the work area. I think the problem with the Z-Poxy seemed worse because I was using it on mat, which starts to come apart while dabbing and shaping it into the hatch as the mix begins to get tacky. All went well with the new resin.

[kevinpratt823]

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Made up my rails and drilled them for both center and front motor locations(I realize I'll prob never find the holes again after I lay in the carbon, and will prob be drilling again in a more revised location), the tall part runs all the way up in case I decide to mount the motor forward. Mounted them up with the motor, shimmed out with 2 good sized washers on either side to allow for the 2nd inlay of carbon kevlar, plus a little side to side shimming to locate the motor where I want it to possibly offset it a fraction to the right, as my strut will be exititng a touch right of center. I epoxied them in, then I laid in what I had left of the carbon kevlar at a 45 deg angle(more strength)to the first inlay.
I was told I would not be able to wrap over the rails, so at the last minute I decided I had to try it(hopefully didn't screw myself). I can always grind down the top and/or lay on some glass in the outer seams(the inner should be pretty solid. The one mistake I made without realizing it, is that apparently the carbon kevlar's edges are bound with scotch tape to prevent unraveling, and I didn't remove it along one edge. Hopefully enough resin soaked in from under to bond it down.

Carbon fiber tube is on the way for a flooded stuffing tube setup.......

Feedback????? How am I doing???

[srislash]

Well,I think it looks good Kevin,mind you I have not attempted this yet.My DF45 is on end waiting for inspiration.

[kevinpratt823]

Well,I think it looks good Kevin,mind you I have not attempted this yet.My DF45 is on end waiting for inspiration.

Thanks Slash, I hope I can help inspire you with my build

[srislash]

Thanks Slash, I hope I can help inspire you with my build

I think I'm going twin with mine Kevin.I have two other large hulls for singles. I'm hoping for a light twin from this hull.But definitely paying attention to you'rs.

[kevinpratt823]

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OK guys, I could really use some input from those of you in the know. I got a CF tube on Ebay for $18 shipped, they are overstock cuts a little over 12" and just under 1" OD, can't post the link per forum rules, but if you want info PM me. I made my hole for he tube as low as possible, and about 1/4" off center, and laid out my hardware as to what I think will work. The 6" rudder bracket seems awfully long for this setup. I think I'm keeping the motor forward to leave me flexibility with batt placement, lmk what you think about what I've got thus far, and if I should do anything differently. The plywood is just temporary until my CF sheets show up from Kintec.
Is this Hydra Ice 200HV(stlii contemplating how/where to mount it) going to handle this Castle 2028 pushing this boat on 10s?
Thanks.

[forescott]

I dont understand the big tube. What is its purpose, and what keeps water from coming inside the hull?

[kevinpratt823]

I dont understand the big tube. What is its purpose, and what keeps water from coming inside the hull?

It is a "flooded stuffing tube" setup. The front will be secured and supported a bit off the floor, and closed off around the stuffing tube. This setup will allow some verticle adjustment of the strut because it allows the stuffing tube to move up and down without also changing the prop shaft angle as it would with a stinger. My Impulse 31 was like this, and I liked the tuneability. RaceMechanix posted a link to his build like this(1st page) from last year and there is some good explanation about it. His is one of the builds I am getting ideas from.

[forescott]

aaaaah, ok.

[lenny]

The CG would be a lot lower if you put the cells inside the rails and against the tube and bottom of the hull.
And you could flip the servo around and mount it in the rail, And that would give more room for cells to move back to,
The 6" rudder bracket seems awfully long for this setup.
The longer it is the more torque and stress it will place on the transom to.

[kevinpratt823]

The CG would be a lot lower if you put the cells inside the rails and against the tube and bottom of the hull.
And you could flip the servo around and mount it in the rail, And that would give more room for cells to move back to,
The 6" rudder bracket seems awfully long for this setup.
The longer it is the more torque and stress it will place on the transom to.

Thanks. I actually test fitted things in the way you described as well, I will definitely consider that also. The battery tray idea would be removeable in case I decide to go the route you described.
I got the 6" rudder mount based on RaceMechanix build, but I think I will order a 4-5" to try out as well. Also thinking of blocking the strut mount off the transom a bit, as it seems pretty close.

[Heaving Earth]

Looks like trim tab brackets are upside down.
Flooded tube looks good