Black Brant III HP

D

Derek Dodds

New member
Just got my plans for a Black Brant III and am looking to start constuction after the 1st of the year. I'm thinking of a yamaha 25hp four stroke. Anybody have any thought on this. Is it enough hp or will i want more? (or need Less?) Also are there any recommended changes/additions guy have done?

Derek
 
Last edited:
I had a 25 HP 2 stroke Evinrude on mine and it was sufficient. It would plane easily with 2 hunters and decoys and run 20-25 MPH depending on the load.
 
I have a 30 hp 2 stroke on mine and feel that it is the bare minimum. I have been in some situations where I felt I needed even more. The last weekend of our season we had to run 3+ miles with a layer of ice on the boat up to 1/2" thick - I really wanted a 40 hp that day. 95% of the time 30 hp is enough if I have the load distributed properly. If you have a choice, get a 30.

Pete
 
I have a 2-stroke 30hp and I wouldn't want anything less.

If you go with a 4-stroke you will need to factor the extra size and weight into your plans. A 4-stroke adds around 100 lbs over a 2-stroke which is a lot in this boat.
 
Hi Scott,

Are you getting used to the hunting out there? Must be quite different than Pool 9 type of hunting.

I agree with you on the weight issue. I wouldn't want a 4 stroke either - just more weight that I don't need in the back of the BB3.

Pete
 
The 25 HP 4 banger should be enough for any normal loads. It will be a good idea to get a couple of props with differing pitch so that you can adjust the thrust to the load when with other people. That motor will be at the top end of what the boat is designed to for motor wieght. I think that is why Sam changed the HP rating from 30 down to 25 a couple of years ago. If the 30 HP and the 25 HP are the same motor with differing carbs then get the 30 HP. The weight will be the same.

You will have to enlarge the motor well to fit the swing of the bulkier motor. When you enlarge the motor well you will be reducing the amount of floatation in the sponsons as well as the amount of planing surface at the stern. There are always trade offs.

You want to build the transom height to your motor shaft length. You want the cavitation plate to be below the bottom of the hull by 1.5 inches or so. OR as recommended by the maker of the motor. This will typically make the transom about 2 to 3 inches higher than what is in the plans. This can also mean that you will have some trouble getting all the pieces you need out of the one sheet of 3/4 plywood. Not to worry since there is enough scrap 3/8 or 9mm plywood to make the smaller pieces by layering.

You also will need to increase the transom angle more than what is in the plans. 15 degrees should be enough.

Some folks like to add cross pieces under the floor. These may have been added to the newer plans.

There will be enough scrap 3/8 or 9mm plywood for you to make a keelson to support the center of the floor/hull so you do not need to buy a piece of solid wood for that. There also is enough scrap to make the cross pieces.

The bow piece typically has to be custom cut and fitted. Make it bigger than you think it needs to be and then whittle it down. The bow eye placement in the plans is OK, but I am finding it a real pain at times with my trailer. I need to cut the bow and winch stand down so that the boat fits better, but haven't gotten around to it yet since it is galvanized and I am loath to put a torch to it. I think installing the bow eye further down on the keel of the hull rather than in the bow piece would make the winching and trailering issues I have much easier. Too late for my boat, but it is something you need to consider.

Add pieces of scrap 3/4 ply to the tops of the knees so that there is more surface area for attaching the deck.

If you have a good welding shop nearby have them make you a custom gas tank to fit in the bow. Having a tank out in the boat is always a PITA when I have a buddy with me. There is always unused space in the forward part of the bow under the deck. Enough for a custome triangular 4 to 6 gallon tank to be fitted in. OR make a platform for a small 3 gallon tank. The 6 gallon tank that came with my Nissan does not fit through the bulkhead.

Make a bench seat for you to run the boat from. My morning runs are typically an hour or more and I tried everything for seating. Nothing really worked for me. Boat chairs were comfy but got in the way when hunting and added a huge amount of weight to the boat. This fall when I was sitting on a park bench and I figured that I can make the same kind of bench to rest on the gunnels of the boat. I got about $20 worth of cedar trim wood and hacked it up to make a lattice, and then glued it with Gorrilla glue. It weighs about 3 pounds and I can stand on it. It stows down on the floor when trailering, and can be used as a back rest for layout hunting. Right now the boat is under a foot of snow so I can't post pics of the bench, but it is the most versatile seat ever. Maybe some "plans" are in order.

Keep asking questions as you look at the plans.
 
I though duck hunting and bass fishing was the same your not doing any good getting their so go as fast as you can with as less weight you can so use the max HP or go over but watch the weight it is the most important safety factor not the HP
 
So far i can't even find a manufacturer offering a 2 stroke in that hp range. At least not on their web sites. Any recomendations, maybe i'm missing something.

Derek
 
Derek, go with a 30hp if you can find one. I have a 25 on my BBIII and with just my self, dekes and dog it is ok but add another hunter and the boat will not plane. This isnt really all that bad considering that my Johnson 25 is a `71 model. Back then the hp was rated at the motor and not at the prop as they are today. The weight and physical size of the new four stroke motors are all issues that have to be considerd. If motor well dimensions and flotation foam volume have to be adjusted for the larger four stokes then the plans should reflect that adjustment.

Another argument for the larger motor is that I believe that most if not all of these boats end up heavier than the specs say they will. For the home builder, especially the first timmer, fillet joint size, extra coats of epoxy and under floor structures all add pounds to the finished boat. While we all try to be fair when estemating the weight of the dog, hunters and decoys and other gear the weight of the blind and especially wet blind material is another factor that adds pounds.

With the elinination of the two stroke motors due to emmision regulations the used motor market is one of the few options that is available. I have been looking for a used (newer) 25 or 30 for a couple of years with no sucess.

Good luck with your boat project.

Mike
 
I thought they were still offering a 30 2 stroke. Or is it just up to 25?
 
I bought a new Johnson 2-stroke 30hp in 2003, and I think they were the only company making one at the time. It's been a good motor for me so far. From what I remember Yamaha last made one in 2002.

Hi Pete - It's been fun to learn a new area. I miss hunting on Sundays, but not the pressure out there. Hope you had a good season.

Scott
 
Look for a good 85-mid 90's Johnson or Evinrude 30-35hp twin. They are super easy to work on and they go forever. Ebay always has something ..if you can find one close so you don't have to have it shipped they can be pretty reasonable. I still have my Navy Seal 35 horse Johnson in pieces and will DEFINITELY get it on the water this spring..all rebuilt..didn't have to..but...I love tinkering.
 
Aren't those new E-tech Mercs supposed to still be 2 strokes? There are even supposed to meet the California emmissions standards.
 
not that i can see on their website and even the 4 stroke is ridiculouly heavy. Best i've found is a honda 30hp coming in at 159 lbs. Guess i'll have to investigate the used market. The prices of a new motor are pretty ridiculous anyway.
 
I rebuilt an aerobatic airplane once used for competition flying and i used to try to save a pound here or a pound there when what i really needed was to go on a diet and lose 30 lbs that i've put on since i got married. I guess that would apply here to if i went with the 4 stroke!
 
I would much rather lift a 117lbs than 159lbs..even though I love 4 strokes. I don't know WHY they can't make a 30hp 2 cylinder 4 stroke that doesn't weigh more than 120 lbs or so..they are missing a market I think. The extra weight isn't so much a problem on the water but it has to be a bitch on the boat when trailered.
 
Ray,

E-Tec are 2 strokes.
The are California compliant.

They weigh less than the 4 strokes, supposidly quieter, faster, and more fuel efficient (if you believe the claims...)

I have 2 buds that have them and of course they love them. I have heard grumblings that more companies are exploring 2 strokes again since the weight issue is a big one for some people and E-Tec are selling quite briskly. I don't know how low in HP they go though, something tells me it is like 75 and higher.

Johnson was still making 30's 2 years ago when I was looking.

I have seen Pete's boat, damn beauty and if he feels it is underpower being the smallish guy he is, I would be very disappointed I think given how much bigger I am than him. No cut on Pete, I just have him by 100#s
 
Evinrude makes a 40hp e-tech tiller model. Go to iboats.com and they have a bunch of new and used motors of all hp ratings. Not sure but maybe someone has a 30hp "classic" Merc leftover..I didn't see them listed on their website but they were there last year.
 
You must log in or register to reply here.
Back
Top