Bracket modification

[flyingfrizzle]

Originally Posted by FishStretcher

If you want a bracket, I wouldn't suggest 6061. You won't be re heat treating it after welding, so the welds will be quite weak compared to the rest of the sheet. Use 5086 instead with much higher "as welded" yield and ultimate strength, and it will have better corrosion resistance, too. Make sure you use the right filler rod. I think it is 5183.

If you were closer, I would say buy my bracket made of 5086. I think it is 125 lb with platform.

You got a good point there about the heat treating, Im not sure what grade would be best but I will be looking into it and doing some research before buying a sheet when I get ready to do the bracket for the race boat. I will check on the 5086 and see if that will be best. I know I want something strong and know that some of the high grade aluminum will work better than others, thanks for the help. I need to study up on it a little better so I go the right direction.

[flyingfrizzle]

Originally Posted by Bushwacker

That's a really stout looking bracket! Any idea what it weighs after all the trimming?

I think you'll want to mount it as low as possible to get maximum flotation at rest. I think Don Herman mounted mine so bottom of tub is about 4" above keel. Motor AV plate is 3.5" above keel in attached pic. We redrilled the holes to raise it another inch, but it still needs to come up about another inch, because AV plate is still under water when up on plane, so keep that in mind when you drill motor mount holes. I need to make an adapter/spacer plate because lower bolts will interfere with the swim platform if I raised them another inch!

Yea it is defiantly stout! A little too stout! It is around 140# right now but the tub is cut to 24" height and I will lower it down to around 21" or so and that will get it down to the 120# mark I hope. There is a lot of thickness were the splash well was molded in at on the last 2" that will be coming off when I cut it down three more inches and that will help shed some weight. I will be putting some back with the swim platform so not sure what the final number will be but it will be a little heaver than most. I got core-cell foam to core the platform with to save on weight and the bracket will have tons of flotation so I think it will be fine. The flotation tub goes all the way out to the end of the second step almost.
Mine will be mounted at around 4" up from the keel to keep the tub in the water as far down as I can so it will have maxim flotation and no drag on plane. The bolt on lip is facing outwards instead of inwards so 4" is the low as I could get it.
Far as the motor mount, I haven't cut it down yet due to wanting to get it right. The bracket is a 24" set back and with a 25" motor I figured setting the mounting tab at 27.5" (2.5" higher for the set back). Everyone says a inch per foot of set back so that is 2 inches plus I will add a 1/2" to that and may need to go even more. Everyone also says they have to raise there motor up more so I may start at 28"-29" mounting height and them go from there. I will be easy to cut it down more but going up not so easy.

What height do all you csc guys think I should set the motor at to start with for a 24" set back???? The help is appreciated.

[flyingfrizzle]

Making a little progress on the mold for the swim platform. The weather slowed me down a bit with the tropical storm moving threw but still managed to do a bit today. Primed with high build primer ready for glass tomorrow.

[kneedeep]

where did you come up with that cool fillet tool ,I've got to have one. my bracket has a 26'' setback and is 28'' up from the keel

[flyingfrizzle]

Thanks for the motor height info, the fillet tool was a gift from my dad. (he builds t-tops/tuna towers for a living and they got a fiber glass shop where he works that build hard tops for the towers) They ordered it from Mini Craft of Florida, INC Phone # (800) 282-8244 on page 43 in their catalog. It work really well, much better than a spoon or other items I have seen used. They are made for installing wax fillet but work well for clay too. They sell four different ones with 8 sizes. Each has two balls on each tool. I don't think they would cost much and be well worth the money.

[flyingfrizzle]

Added 3 layers of matt down in the mold today. Tomorrow I will add a layer of 1708 and some 4" stripping around the lip. I also got to cut the foam to add for a core material.

[flyingfrizzle]

Sanded down the first 3 layers so the next layers would bond down good. Added a layer of 1708 then put down the foam core material then a second layer of 1708 over the foam. Added some narrow strips to the corners of the liping and then added 6 layers of wide stripping to the front edge that will mount to the boat to build it up. The foam I used has holes drilled threw it to let the resin bond better.

[flyingfrizzle]

Popped the swim platform out of the mold today. Turned out well considering it is the first one I have ever made. Few little spots to touch up but it is super strong and looks like it will work well.

[captmattson]

Im very intersted in the results and pics. I have the exact same bracket and may do a similar mod for my new 20sf project

[flyingfrizzle]

Originally Posted by captmattson

Im very intersted in the results and pics. I have the exact same bracket and may do a similar mod for my new 20sf project

Not finished yet, but will update. Baseball with the kid has been killing my time.