Braket build
 

Hi guys what are the set backs for the brackets 27" 28" 30" i have a120 johnson.. Would like to be able to upgarde to 150-or 175 in future... What would you all recommend for my 20sf..oh and i cam up with about 12-13degrees transom angle

Brackets create a big CG shift aft, so best to minimize both setback dimension and motor weight, and get a bracket with maximum flotation (Hermco) to have any chance of it being self bailing at rest. Don said he can build his brackets with setbacks of 18, 24, and 30 inches. Also consider moving console and fuel tank forward as much as possible. Min planing speed and ride will also take a hit, so plan on running a 4B prop and maybe a fin on AV plate to get more stern lift.

Calculating bouyancy and size of bracket with 30" set back and getting something like 525lbs of boyancygive or take.. But with moter and 40 gallon livewellabout 12" in front of transom.. I am negative about 475... I do have trim tabs.. Shoukd i build bracket with max lift and then start placing tank console and coffin box in... Or maybe put some weights in the hull and see where things need to be.. Thanks for the reply bushwacker

I have lightend up the hull alot as i have removed the platform and all wood but replaced transome and keel with compound at 40 lbs a 5 gallon miss calculated the transome so that is about 200 lbs keel is 40 lbs , top cap added about 50 lbs hull sides about 80 lbs... Floors are going to be about 70 lbs.. And 60 gallon tank up front... Put hull in water and she floats high bow heavy and water levelabout 4" below chine..... I am going to build bracket and install on boat with out platform to see where it needs to ride... I wish the transom did not endup that heavy.. But it is waht it is.. It is a 73 sf with large stringers do i need to raise floor 2" for self bale out the stern

The flotation at rest isn't nearly as important as balance and performance up on plane. When you're up on plane with the tank out of the water, the boat will still know you shifted it's CG aft by about 18" or so! A 40 gallon livewell near the transom doesn't help either. I'd suggest putting it forward of the CC.

When I repowered from a 300 lb motor on the transom to a ~420 lb motor sitting 30" further back, my min planing speed went from 12-13 mph to the low 20's and that's with trim tabs! And the Seafari has more weight forward than the CC to begin with. I finally got it back down to 12-13 mph by going to a 4B prop and a fin. Don't know how fast you want to run or what sort of seas you run in, but if you're running offshore in seas of 3' or so, 120 hp is plenty of power for a 20. Ran mine for over 30 years with a 1975 "115" (crankshaft hp) that really only put out about 90 hp at the prop. Cruise speed on Bahama trips with very heavy load was about 20 kts, but it rode very well and I could hold that speed in seas up to about 3'. I couldn't use much more power in those conditions, so you might want to try it with the 120 first!

Baitwell forward will that beat the bait up .. Did notnwant water splashing in my face other then spray from bow

3' is about all i want to fish in.. Would like to run about 28or so... I can make the live well smaller

I have my livewell under the leaning post. loves the weight there. Mind you my boat is an `89 and I "think" the deck may be higher. This is all factory. 25 " trasom, scuppers out the transom, and self bailing w `96 150 rude @ 375lbs.

Anyone know if the deck got raised in the late70s or 80`s?

Cheers,
GFS

Potter had raised the deck by an inch or two on the Seafari by '76 and probably did it on other 20' models as well. He may have done that as early as '73 when he changed stringer configuration from 4 individual hollow pre-molded stringers to the 2 box stringer configuration. A friend of mine bought a new Seafari in '76 and the little wells around the scuppers that are about an inch deep on mine were about 2-3" deep on his. His boat also had the bigger 50 gal fuel tank, the smaller step down that was just big enough to open cabin door, and front of windshield was moved forward about a foot with a fixed section of glass below the opening section. It also had storage box on passenger side just aft of windshield similar to the 23 Sceptre.

Decks
 

Yea i just struck a line across deck and bow 2 inches and the Freeboard is 17 inches from that line.. not much to keep you inside.. I did not draw lines on the outside when she was in the water..before teardown.. Would have liked to get a starting point.. I just cannot see this boat at rest displace that much more water. I pulled old picts of the boat in the water with some gear. and it rested at about one inch above chine in the stern...I am going to leave it the way she is Although I will have trouble killing the deck into the forward area as I start to get into the chine.... I will probably bring the upper bow gunnel back some about 15 inches and get more area to stand on and throw 10ft cast net.. then killit itno the deck.. That way i will have more anchor storage. as well.. here are some pictures .. You can see a good scum line on the hull. I will just keep it a 1" above the stringers. Building bracket first and attacing to boat then loading with parts to see where I need to be with weights and all. Thanks for the help...

My waterline at the transom is now about 5" above the chine when I'm fully loaded for a long cruise with a couple of big 70 qt coolers, 6 gallons of water in the galley seat and an extra 10 gallons of gas in jugs. Check out this post I sent to Strick a few months ago regarding bracket mounting height. http://www.classicseacraft.com/commu...height&page=10

Here's a link to a slide show of my boat's waterline before and after bracket. http://s188.photobucket.com/albums/z...t=5e5bed30.pbw Those old V-4's are pretty light and you can see that my trim tab mounting plate is almost out of the water, so that would put the waterline with the old motor about 2" above the chine at the transom.

Thanks bushwacker, does the top of the swim platform parralell to the keel on bracket tub

Is the swim-platform?

Yes, the swim platform appears to be parallel to the bottom of the flotation tub. The bottom of the tub on a Hermco bracket projects straight back parallel to the bottom of the boat, which creates more volume/buoyancy and also should act like a trim tab to provide some additional stern lift when climbing on plane. The extra buoyancy will also help keep the powerhead higher out of the water when the stern wave tries to climb up over the transom if you suddenly cut power and drop off plane quickly. The Armstrong brackets appear to slope up at the back, evidently to keep them from dragging in the water, but I don't see any advantage to that. Those brackets don't seem to be as well thought out as the Hermco, which was designed by Bill Potter for a SeaCraft.

Thanks man I aprreciate the info..

For what it is worth- if you pay close attention to where you put weight, and limit the total weight, you can do ok without a bracket.

My waterline at the transom is 4" from the chine on port, 5" above the chine on starboard. The difference is a 60 lb kicker motor on the transom. About as good as Bushwacker when I am empty and his bracketed boat is full. Not as good, but not awful. I hope I plane out a little better, but I am not sure.

I have a light motor- 366 lb four stroke Yamaha 100. The 20 gallon fuel tank is in the console, as are the batteries. I have aluminum anchors. I have no livewell. The 150 qt cooler is forward of the console and doubles as a seat.

The modest power still goes 100+ miles on 20 gallons, and a 5 gallon spare tank is good for 25 more.

Just don't have 2 guys in an aft corner in the following sea. That is the situation where a bracket could be a lifesaver.

Here's a link to an older post on a discussion of brackets which contains a link to my Bracket Pros & Con's post
http://www.classicseacraft.com/commu...cket+Pros+Cons .

Trader, that link to my old post doesn't work . . . I think it was posted in first half of 2009 or late 2008. Is there any way to retrieve posts that old? Although it's several years old, all the info in it is still applicable. Denny

[QUOTE=FishStretcher;208381]For what it is worth- if you pay close attention to where you put weight, and limit the total weight, you can do ok without a bracket.

My waterline at the transom is 4" from the chine on port, 5" above the chine on starboard. The difference is a 60 lb kicker motor on the transom. About as good as Bushwacker when I am empty and his bracketed boat is full. Not as good, but not awful. I hope I plane out a little better, but I am not sure.

I have a light motor- 366 lb four stroke Yamaha 100. The 20 gallon fuel tank is in the console, as are the batteries. I have aluminum anchors. I have no livewell. The 150 qt cooler is forward of the console and doubles as a seat.

The modest power still goes 100+ miles on 20 gallons, and a 5 gallon spare tank is good for 25 more.

Just don't have 2 guys in an aft corner in the following sea. That is the situation where a bracket could be a lifesaver.[/Q


Fishstrecher.. are you serious about those numbers.. That is insane.. and to think I was going to make my tank Larger . I have a 40 gallon stainless I would like to keep it in the boat from the looks of it that would get me 200NM plus on a four stroke.. all i need is 125 NM tops Man those are awesome numbers

Bracket
 

Okay i built my bracket mold today. My bottom pieces were a little off. I drew it all out and cut all parts. Then brought home to assemble and must have been the compound angles..It should be fine for a one off. I know why Now that Strick used 2 sides melamine.. Forgot to flip part over and cut out.. I have one side with No melamine. LOL..Ill make it work...Before I wax and go further I would like to know if these Dimensions are okay. 47 wide 23 high at the motor .. 19.5 at the front that bolt to transom I figured it should get me around 400lbs displacement.... I was going to build tub and install then load the boat with differnet weights according to where i want to put things. Live well coffin console ect..fuel tank. just curious as where the boat will lie..

I am serious.

But looking at your boat, you have a bimini and an older 2 stroke.

I get great mileage because I have a modern 4 stroke, not an older 2 stroke, and the engine is small- 1.6 liter. Both of these facts are important. (A MODERN 2 stroke of small displacement might get great mileage, too, I don't own one)

So I burn a lot less fuel at no wake speed and intermediate speeds like 18 knots with a small engine propped for 0-33MPH. Running at no wake speed where you need to use throttle because the engine is small is much more efficient that loping at idle thru the marina. At 28 knots- the fuel economy is still better than a 150/175/200, and the max fuel burn is obviously only 1/2-2/3 of one of these engines. The go faster, so the pentalty in MPG flat out with a 150 isn't terrible, but it isn't the same.

A modern 90 hp is probably the recipe for good fuel economy- Fr. Frank used to get similar numbers. But you won't be doing 40MPH on the water- only on the trailer.

If you keep the older 2 stroke, keep the 40 gallon tank and move all the weight forward you can and spend a little money on the right prop if yours isn't spot on. THAT was the best $100 I ever invested. It took 2 tries to get there. Less pitch is more...

[QUOTE=martin;208383]

That was great advice.. I am keeping the old tank. And that is that..thanks for all the pointers

Started the bracket ..waxed the mold and put three coats of no wax gelcoat...then i started with the glass I put an 2 oz choppy. Then 1708 in all corners .. then 3 layers of 1708 0/45 and on layer of 18oz biax. 0/90.. overlap all corners ...wwas wondering what laminate scheduleneeds to be

Okay i had problems with the gelcoat and resin.. After i put a layer of2oz i started to see the glass bubble a little in some place.. And another place it had pulled from the mold.. I used mold wax and then brushed 3 coats of gelcoat no wax.. I then started laying glass the next morniging.. I tilted the mold up in the back so that the front and back were 90degrees to the floor.. It was in the front that it stared to pull from mold. I braced it up and then started laying three layers of 1708 i let kick off and pulled braces... Have you guys had this happen with gel coats

post pics please. easier to help with visuals.

strick

Hi strick i wish i could as i already layed the glass on.. It only did this when the matt was kicking.. I had already layer some 1708 tabing so i think that it was from the 1708 tabing and nothing else keeping the mat to the mold as the tabbing started to cure or shrink. It pulled on the mat. So i just put wedged sticks in the mold to hold the glass to the side and layed more glass in..we will see after we are done..
Strick how many layers are over your braces..did you put .as many layers as your sides .. Or less.. And also did the motor mount go in after the 3/8 thickness was attained on the outside.. How many layers on top of the foam/plywood. Motor mount
I will be laminating 25lbs foam core with reinforced glass kinda like coosa board but nida core, foamboard..
It is 1/2 inch so i will laminate three pieces to bring it over 1.50".. Probably vacuum bag it to back..or do you think that vacuum might pull it off the mold

glass pulling from mold
 

Okay CHECKED bracket and saw the glass is pulling from mold...got 4more layers to go .. I guess it was the heat and release wax ..bizarre

Alligators suck I had my share of them...many causes...

strick

bracket mold
 

Eight layers of glass 7-17/08 biax 45 degree
1-18oz biax 90 degree
1-layer of 2oz mat
Will start glassing in Transom pad

have some air bubles on the last glass layer I think it was getting to hot the mold that is

I dont know anything about vacuum bagging as I have never done it so am not qualified to answer your question on that. Transom core goes in after the tub is layed up. There are 3 layers of 1808 over the transom core. What are you referring to as "layers over braces"?


strick

Not sure of the techno term . But the three, pieces that make the bracket stiffer,,, perhaps, stiffiners..did you laminate three layers of 1808 on each side.... By the way what denisity was the foam you used..

You must be talking about the stringers? They are 5/8" or 3/4" corecell I cant remember now....they are glassed and then tabbed in with 1808. They are not laminated into the tub as you have eluded to. If you want to do it that way I would do 2 layers.

strick

Thanks strick I have been busy at work .will try to have done by Mon

Laying up bracket mount for engine. 4 layers of 1/2 20lb density foam. layer of 17/08 and 2 oz mat on each sandwiched layer . drilled bleader holes for the resin to soak through and pull vacuum to ful vac of -30 then backed of to -20

bracket lay up
 

here is the engine mount

stringers for bracket
 

Layed this up after I pulled vac on engine mount.... then pulled vac on both parts

stringers for transom bracket
 

here are the stringers

Hey guys okay got the stringers in and the motor mount shapedvwill install in the mornig.. strick.. How heavy are your brackets when you are done

Pretty cool thread. I can't speak for Strick, but I have an all aluminum bracket I was considering mounting. It appears to be 130 lb for 30" setback. Maybe 110 lb for a 24" setback if/when I cut it down. It does lack a center stringer which I would need to add. I seem to recall reported similar fiberglass bracket weights of 120-160lb.

I opted not to use the 30" bracket yet- it needs a brace/stringer, and I only need 23" of setback, so I didn't want to move the weight that far aft as I was worried about handling. But a 24" bracket is a little tight. I might use that aluminum bracket as a plug for a 24" bracket mold.

I really like the idea of a vacuum bagged bracket. I am wrestling with how to do that and don't have a firm plan yet, shy of a collapsible inner plug- which seems really ambitious.


I don't want to hijack your construction thread, but if you are interested a design/theory thread for brackets is here:
http://www.classicseacraft.com/commu...t=23274&page=4

I got a weight on one several years ago but I have forgot what that was. I will weigh both brackets when done and post it on the thred I have going.

strick