Grumman Sport Boat Update

Jeff Reardon

Jeff Reardon

Well-known member
Supporter
I have the boat in hand now, and picked up a new 6 hp Suzuki to drive it. Paint on the way from Lou at LS+B. Took her out for a test run last Friday, and the 6 (1) all I want to carry and (2) good for just under 10 knots at half throttle break in speed. I'm guessing I won't get much more by pushing it harder, and glad I did not get an 8 or 9.9 with the extra weight.

One of my intended uses for this boat is river fishing, and with shad season just around the corner, I'd like to mount a roller on the bow for an anchor. I have the hardware from a canoe, but am wondering about how to mount on aluminum. This is more difficult on the GSB than it otherwise might be, because about 3' of the bow is filled with floation inside and covered with a rounded deck. There is also a metal tab with a bow eye mounted dead center at the bow. Do I need to take bow apart and pull out the floation, then bolt the bow roller through the aluminum to a piece of scrap wood and then refill the bow with floatation foam? Any ideas on how to get a safe mount without taking the bow apart? I'll try to grab some photos this weekend when I have time.
 
Jeff Reardon said:
Any ideas on how to get a safe mount without taking the bow apart?
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Rivnut.

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For informational purposes see this link, https://www.rivetnutusa.com/rivnut-rivet-nut/

Many vendors on Amazon sell various quality rivnuts and installation tools. I had the advantage of having the tool available at my place of work. Once I retired, I did invest in my own tool and a supply of various sizes just to have on hand. These can be purchased in Stainless steel.

A less expensive alternative which can be installed from the top side is a "Well Nut". No special tools required.

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Jeff,
If you don't get satisfactory answers here, go to the forum "Michigan-Sportsman.com". Go to their Waterfowl Forum. The adaption of Grummans SB's is a common practice there, including putting a winch on the bow, operated by a chain saw engine. This is done to pull the boat over dikes on such areas as the Shiwawassee and Harsen's Island Waterfowl Areas.

Larry
 
Jeff Reardon said:
I have the boat in hand now, and picked up a new 6 hp Suzuki to drive it. Paint on the way from Lou at LS+B. Took her out for a test run last Friday, and the 6 (1) all I want to carry and (2) good for just under 10 knots at half throttle break in speed. I'm guessing I won't get much more by pushing it harder, and glad I did not get an 8 or 9.9 with the extra weight.

One of my intended uses for this boat is river fishing, and with shad season just around the corner, I'd like to mount a roller on the bow for an anchor. I have the hardware from a canoe, but am wondering about how to mount on aluminum. This is more difficult on the GSB than it otherwise might be, because about 3' of the bow is filled with floation inside and covered with a rounded deck. There is also a metal tab with a bow eye mounted dead center at the bow. Do I need to take bow apart and pull out the floation, then bolt the bow roller through the aluminum to a piece of scrap wood and then refill the bow with floatation foam? Any ideas on how to get a safe mount without taking the bow apart? I'll try to grab some photos this weekend when I have time.
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Hope the boat works out for you. I looked at new Sport Boats, they're a bit pricey for their size. I picked up a brand new 12' john and a Suzuki 4 for over a thousand less than the Sport Boat alone. I think the 4 & your 6 are the same powerhead. Gave that shiny black motor a good dose of spray camo a couple hours after I uncrated it. The spots in ME where I plan to use the boat are sheltered spots so the dog and I should be fine. I may test it with a second person this summer when the water is warm enough for a dunking, but it looks a little small to my eye.
 
This boat might be older than I am, and I sure didn't pay retail! Been looking for a car-top boat for lakes, ponds, and salt marsh spots with no trailered launches.
 
Jeff Reardon said:
This boat might be older than I am, and I sure didn't pay retail! Been looking for a car-top boat for lakes, ponds, and salt marsh spots with no trailered launches.
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Me too. I think you once mentioned that you hunted a first day or two at one of the spots I have in mind for the boat. Maybe we can race our new overpowered boats? Like those southern guys in mud boats through timber, but at Maine speed in a bog. ;)
 
SJ Fairbank said:
Me too. I think you once mentioned that you hunted a first day or two at one of the spots I have in mind for the boat. Maybe we can race our new overpowered boats? Like those southern guys in mud boats through timber, but at Maine speed in a bog. ;)
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First, I may need to race you to some brook trout. My 14' boat is too wide to make the push through the thorofare from Pierce Pond to Upper Pierce, so that may be the GSB's maiden north woods voyage. Other potential spots--Lobster Lake; Penobscot Pond; Deboullie, Telos. It's a long list!
 
Jeff Reardon said:
First, I may need to race you to some brook trout. My 14' boat is too wide to make the push through the thorofare from Pierce Pond to Upper Pierce, so that may be the GSB's maiden north woods voyage. Other potential spots--Lobster Lake; Penobscot Pond; Deboullie, Telos. It's a long list!
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You're right, I'm getting ahead of myself. The salmon in the East Outlet at Indian Pond are in trouble next week. I need to get on Lobster, haven't been there in some years. The bigger boat might be called on for those lakes. So many spots needing attention. I'd like to hear how you like your new boat, I can always be persuaded to enlarge the fleet.
 
Jeff Reardon said:
I have the boat in hand now, and picked up a new 6 hp Suzuki to drive it. Paint on the way from Lou at LS+B. Took her out for a test run last Friday, and the 6 (1) all I want to carry and (2) good for just under 10 knots at half throttle break in speed. I'm guessing I won't get much more by pushing it harder, and glad I did not get an 8 or 9.9 with the extra weight.

One of my intended uses for this boat is river fishing, and with shad season just around the corner, I'd like to mount a roller on the bow for an anchor. I have the hardware from a canoe, but am wondering about how to mount on aluminum. This is more difficult on the GSB than it otherwise might be, because about 3' of the bow is filled with floation inside and covered with a rounded deck. There is also a metal tab with a bow eye mounted dead center at the bow. Do I need to take bow apart and pull out the floation, then bolt the bow roller through the aluminum to a piece of scrap wood and then refill the bow with floatation foam? Any ideas on how to get a safe mount without taking the bow apart? I'll try to grab some photos this weekend when I have time.
Click to expand...

I'm not seeing the pics?
 
I'm behind on pictures, but I'm not doing anything interesting yet. I did take it to a car wash and pressure wash off the worst of the lichen and dirt. Dead Grass Green paint from Lou Tisch has arrived, along with his recommendation that I follow Eric's advice and use automotive primer, which I have also acquired. Other than that, took it out for a fruitless day of trolling a fine brook trout pond to finish breaking in the new motor. Very glad I did not go with anything bigger than 6 hp. She runs at 7 mph are 1/3 throttle, and I almost hit 9.5at WOT. The traditional formula for hull speed tells me that would be 6 mph, and it is not a hull made to plane. 7-8 mph is all I need for the uses I have in mind.
 
New question. (And yes, Todd, it would be better with photos, but I don't have any . . . . .so there!) The previous owner had replaced whatever motorboard these came with 55 years ago with low grade plywood. That will eventually wear out and need to be replaced with something more durable (like sealed marine plywood?), but for now is functional until the wear is an issue. My concern is that there is a metal cap on the transom that overlaps the interior motorboard, and the gap between its down-turned edge and the board is situated such that it snags the ends of the motors mounting bolts when I loosen them and take the motor off the boat. (Which is often, since for now I am car-topping rather than putting it on a trailer. To keep the boat functional at the height of spring trout fishing, I'd like to fill that gap so I quit snaggin it. What to use, that will (1) adhere to both wood and metal; (2) fill the gap and allow for a tapered edge at the joint; and (3) not interfere with replacement of the existing motor boards when that is necessary down the line (probably next spring). Thickened epoxy? JB Weld? Other thoughts? Peak use for the boat is the next 5-6 weeks, so I'm looking for a temporary solution here, not a long-term fix. When I replace the motorboards, I'll get them to a thickness that matches the aluminum cap, but in the meantime there are brook trout, shad, and striped bass that need chasing.
 
Jeff Reardon said:
I'd like to mount a roller on the bow for an anchor. I have the hardware from a canoe, but am wondering about how to mount on aluminum. This is more difficult on the GSB than it otherwise might be, because about 3' of the bow is filled with floation inside and covered with a rounded deck. There is also a metal tab with a bow eye mounted dead center at the bow. Do I need to take bow apart and pull out the floation, then bolt the bow roller through the aluminum to a piece of scrap wood and then refill the bow with floatation foam? Any ideas on how to get a safe mount without taking the bow apart?
Click to expand...

Jeff the rivnut that Dave mentioned works great especially if you want it removable, we use them here on the planes at work.

If you want something that is permanent then you could also use a Jo-bolt. It's a blind fastener that has a center stem going through the fastener. You put a wrench on the head and then spin the stem which swages a collar on the back side to hold it in place. If you want to use a Jo-bolt then just pm me and I can probably help with getting you some.

catalog.monroeaerospace.com

NAS1751 Protruding Head Jo Bolt Blind Fastener - Monroe Aerospace

Monroe Aerospace is a stocking distributor of Aerospace and Mil-Spec hardware including jo-bolts.
catalog.monroeaerospace.com catalog.monroeaerospace.com
 
Jeff Reardon said:
My concern is that there is a metal cap on the transom that overlaps the interior motorboard, and the gap between its down-turned edge and the board is situated such that it snags the ends of the motors mounting bolts when I loosen them and take the motor off the boat. (Which is often, since for now I am car-topping rather than putting it on a trailer. To keep the boat functional at the height of spring trout fishing, I'd like to fill that gap so I quit snaggin it. What to use, that will (1) adhere to both wood and metal; (2) fill the gap and allow for a tapered edge at the joint; and (3) not interfere with replacement of the existing motor boards when that is necessary down the line (probably next spring). Thickened epoxy? JB Weld? Other thoughts?
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I would expect that simple window, door and gap caulking would fill that gap. Take a wet finger and tool it down to a feather edge along the gap and the clamp washers should ride right up it when removing the motor. (provided you have the clamping bolts backed off far enough)
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Did this for an entirely different reason but it works great. Cut a 1/8" piece of aluminum to cover internal pad going to top of transom and screw w/stainless screws to your existing pad. I originally did this to stop the digging in of motor screw clamps on an interior pad on my ghenooe. Works great and reduces all damage to motor board.
 
roy brewington said:
Did this for an entirely different reason but it works great. Cut a 1/8" piece of aluminum to cover internal pad going to top of transom and screw w/stainless screws to your existing pad. I originally did this to stop the digging in of motor screw clamps on an interior pad on my ghenooe. Works great and reduces all damage to motor board.
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So bent over transom and screwed in on both sides?
 
Jeff Reardon said:
So bent over transom and screwed in on both sides?
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You could do that but in my case I already had an aluminum plate from factory on outside of motor board screwed in to fiberglass stern. I just duplicated it on inside to dimensions that stopped screw pads from digging into fiberglass. You do want to make sure you keep those transom screw pads tight just for the reason that they're not digging in. I,ve never had mine loosen up and my motor stays on Ghenooe year round but it is possible they could loosen.
 
My family had and heavily used a GSB for about 40 years. I did some of the modifications you are contemplating and wished later that I had left the boat as stock as possible. The only mods I would be interested in now would be a drain plug and possibly a jack plate. I ran a 8HP Mercury.
 
I'm contemplating no mods except for an anchor roller off the bow and beefing up the soft plywood motor boards. Plus paint. A drain plug would be nice--anyone have a link to a good way to do it?
 
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