I built Bantam and Grinder, both modified Phil Bolger designs. Grinder turned out very well, but I thought I could do better. My idea was to build a boat similar to Grinder, but much lighter, with a different profile and a bit longer cabin. Since a flat bottom boat gains efficiency as it loses weight, I wanted to try a smaller engine that needed less battery, all Okume construction, a laminated 3/4" hull, and get rid of the heavy shoe Phil had on the clam skiff. I changed the sheer line to something I liked, eliminated the raised coaming of Grinder, and added an extended gunwale to stop spray and provide a walkway and seating all around the boat. The cabin is 9'6" long, and Grub is 21' overall.
The construction pretty much follows the method I used on Grinder. Here are some build photos.
In place of Phil's 1 1/2" x 16" shoe in the center of the hull bottom, I used twin 1 3/4" skegs. This turned out not to be enough to stop a disturbing "bump and wiggle" hull flexing when underway.
My immediate fix was a cross batten mid-hull in the cabin, which solved the worst flex, but I still was not happy. I wanted stiffness but not weight, so I took the cabin off after the first season, turned the boat over and put a keel on. The photos will help explain. It's made of left over 3/8" Okume, 1 3/4" high and 16" wide.
Here are few beauty shots, and an action video:
Hi, thanks for sharing this wonderful boat. Is the keel addition hollow? Do you have a provision for draining it? Thanks, Tim
ReplyDeleteGrub is very much like Grinder, but @ 300 lbs. lighter.
ReplyDeleteTake a look at the Grinder link above for stats. The changes to Grinder are explained in the Grub blog.
I like how your boat turned out. Grinder looks good, but the changes you made to Grub makes it much more pleasing to the eye to look at. Gives it that something special which draws they eye and makes it stand out.
ReplyDeleteI am planning on building a Bolger Sneakeasy. I was looking at the box keel version but I like the looks of the standard flat-bottom better. I had seen the Clam Skiff with its wide shoe but had not seen a good photo of it until Grinder. I was thinking of adding it. I also like what you did with the wedge keel on Grub. Which one actually performs better at higher speed and in hard over turns? Saving 300 lbs on a 21 foot boat is quite an accomplishment! I Am going to pay a lot more attention to my materials selection on my boat!
ReplyDeleteNever really try hard turns at speed because of Phil's warning about "tripping".
DeleteThe keel I put on Grub works great. Don't know what it would do for a Sneakeasy.
Tom,
ReplyDeleteYour progression is fascinating - bantam to Grinder to Grub to flaired Grub. I was looking at Bolger's house boat 481 for cruising the Eriea nd similar sheltered waterways. Grinder/Grub have me rethinking - trading some interior amenities (enclosed head) for a camp cruiser capable of more speed and wave action. Thank you