transom degrees?

JohnCranston · Post by **JohnCranston** » Nov 26th, '11, 23:21

Thanks in advance,fellas,

We're getting ready to mount the Cabrera's swim platform, and, are looking at s.s. brackets made by A F I. Their brackets are triangle in shape and have a 105 degree angle. Does anyone know the angle of the 31's transom in reference to the bottom of the boat?
Many thanks.
John.

jrhaszard · Post by **jrhaszard** » Nov 26th, '11, 23:37

I believe I used eleven degrees aft of vertical when I replaced the pieces inside the transom.That would make it 90 plus 11 or 101 degrees in relation to the bottom.

JohnCranston · Post by **JohnCranston** » Nov 27th, '11, 22:05

jrhaszard,
That's close enough.
I appreciate your response.
John.

Rocky · Post by **Rocky** » Nov 27th, '11, 22:39

John now we have three numbers close to each other, on my '70 Sportfisherman using the bottom as 0 degrees I have 103 degrees of transom angle. I don't know if the year changes things as far as this angle though. I remember the earlier 31 had one more strake at bow section and deeper-V slightly. Hope this helps.

JohnCranston · Post by **JohnCranston** » Nov 28th, '11, 01:01

Rocky,
Thanks for the info,
I double checked the AFI bracket angle, and, it turns out to be 102 degrees...looks like I won't have to re-invent the wheel this time.
The brackets are 14" x 21", and, I was thinking that 4 of them should distribute the load. I need to check the width of the platform first...we've never even taken it out of the box yet.
Many thanks.
John.

f

Bill Fuller · Post by **Bill Fuller** » Nov 28th, '11, 10:25

John
I have used these brakets on my B28 for the last 21 years. They have the perfect angle. I have one suggestion and that is to us 6 of them. I use 6 because I knew I would have significant weight on the step. But, I have broken 3 of them over the years. All on the far outside bracket. The break occurs in the 103 degree bend. The brackets seem to have been welded under a bit of stress. I suspect that stepping, jumping, onto the edge of the step over the years contributes to this. ALthough I like the brakets and they are easy to use, if I were doing it again I would probably go with something a bit heavier. If you are not going to have weight on the transome, they will probably be fine. But I would certainly use 6 of them.
Good luck
Bill

Rocky · Post by **Rocky** » Nov 28th, '11, 12:45

John here are some pics of my Danny at High Tide platform, he calls the original Bertram design. He gave me fabricated brackets with welded angles for feet of heavy gauge stnls. Under his tech's instructions I was to put every 20" (4) brackets across evenly, and the flange to hull surface through bolted with heavy wide washers and 3/8" bolts in 316 every 8".The brackets extend/terminate 20" measured from hull at top of platform to carriage bolts. Of course the radius of the hull did not match platform flange radius exactly, but when I tightened bolts down with the 5200 between hull and flange as he instructed it came to the hull's shape easily. The result is a very strong mount under your feet. Triangle brackets I'd imagine are even stronger as you have.

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JohnCranston · Post by **JohnCranston** » Nov 28th, '11, 14:08

Bill,
Did you go with the 21" brackets? I know that AFI makes a smaller version. What else is on the market without having something fabricated?

Thanks.

Rocky,
Thanks for the measurements and pics...I'll have my buddies take a look before tackling the job.
Thanks again,
John.

Bill Fuller · Post by **Bill Fuller** » Nov 28th, '11, 17:45

John
I used two sizes. The shorter ones on the outside and the longer ones on the inside. For backing, I did not think that large washers were sufficient. I used a 2 inch wide, 1/4 inch think stainless strap for the backing plate for each bracket. I am sure that these brackets are fine, and I have only broken the outised ones even though I routinely carried two 162 quart ice chests on the step, usually either full of ice or fish. The four inside ones are untouched in 21 years. But, like I said, a littel beefier would not be bad.
Rocky's arrangement is completely different with the entire step bolting directly to the transom. This arrangement must add a lot of strucutral support to the whole thing. My step only bolts to the AFI brackets.
Bill

Rocky · Post by **Rocky** » Nov 28th, '11, 22:32

No problem John, good luck with the install.

Tommy · Post by **Tommy** » Nov 29th, '11, 11:16

Very nice setup, Rocky. Our platform came from Butler Marine, and they were also an OEM vendor for Bertram Yacht. Like yours, the platform fits perfectly with the four heavy duty SS support bars. Instead of large washers, our yard used 4"X4" aluminum channel as backing plates. I know platforms are not popular with hard core fishermen, but they sure come in handy when boarding from the water. Of course Uncle Vic doesn't like them because he said it keeps you from "seeing that fabulous deep V at work in heavy seas...".

IRGuy · Post by **IRGuy** » Nov 29th, '11, 14:32

I was taught that every time I start a boat's engine(s) to look over the transom to be sure cooling raw water is coming out of the exhaust ports. If I ever build a stern platform I will somehow build in openings so I could still do this.

Rawleigh · Post by **Rawleigh** » Nov 30th, '11, 09:22

Frank: My B31 has outlets on the side that bleed off part of the cooling water so that the smallish exhausts don't get overloaded. Easy to tell if the water pumps are working from the bridge.

Tony Meola · Post by **Tony Meola** » Nov 30th, '11, 22:58

Rawleigh wrote:Frank: My B31 has outlets on the side that bleed off part of the cooling water so that the smallish exhausts don't get overloaded. Easy to tell if the water pumps are working from the bridge.

Rawleigh is that factory? I don't remember them doing that.

Pete Fallon · Post by **Pete Fallon** » Dec 1st, '11, 23:12

John Cranston,
I measured my transom angle 1961 31' Express, angle finder is reading 15 degrees at the water line and 15 degrees where the brackets should meet the transom below the waterline. Dead rise at transom between V on bottom to first lifting strake reads 23 degrees.
Pete

JohnCranston · Post by **JohnCranston** » Dec 2nd, '11, 13:04

Pete,
I'm going down to the boat this weekend and will measure mine and see where we're at.
Thanks for the info, everyone.
John.

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transom degrees?

transom degrees?

Transom degrees

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