13 Bananas New Jersey Kodiak

[cj8mule]

That's a lot of cockpit - you'll want to try to keep heavier weights aft, don't put a big fuel tank forward, etc ... balance the boat right, in other words. You'll get better gas mileage if your at-rest trim is slightly up.  The trim, a little up or down at the bow, doesn't matter so much except that the boat is more optimal with a wee bit of bow-up trim.  It's a good goal to have.  The latest Kodiak addendum has advice on how to do this, and when you get there, it's not a bad idea to float the boat at a dock and add buckets of sand or tube-sand in various places to emulate what's left to go into the boat ... then tune as necessary.

Thanks for the advice Brian.  The plan right now is for the generator and 2 house batteries at the transom.  Below deck he would like 2 ea 100 gal fuel tanks that will start about 12" forward of the transom going forward, then a small water tank.  (I've not calculated if there's enough room for both fuel tanks to be 100 gallons).  I think 150 gallons of fuel would be plenty and expect at least 3 nm / gal from this boat at cruise.  It'll be powered with a pair of 2007 mercury 4 stroke 150's that have 100 hours on them.  They've been pretty much pickled and appear brand new. 

There will also be 3 batteries for the spot lock trolling motor somewhere midship to forward up to the front pilothouse bulkhead.

I've put a lot of hours on my 27' Jumbo and believe your advice to be perfect for someone building a Tolman also.  I've noticed a huge difference in fuel mileage and performance by making small changes like moving a 100 pound life raft from the cuddy to around station 6 in the pilot house.  I know you made a completely new plan for the GA, but there are enough similarities between them in construction material, weight, etc.  I made many trips offshore in the NE Atlantic with a 500 pound tuna cooler sitting 3 foot forward of the transom and an extra 300 pounds of jerry can fuel in the pilothouse.  (LOL... those were the 2 stroke days as there was already 87 gallons of fuel in under deck.  ha ha) 

[cj8mule]

with all the of the concerns regarding weight in the Kodiak I'm glad I went with the standard GA.   It would be nice to have another 2 feet of cockpit, but I never intended to have more than 2 buddies along on trips.  I feel the pain for everyone building now and I'm glad I was able to when I did.  Prices for materials are crazy.

I agree Todd, material prices are just plain stupid right now.   Nothing is set in epoxy yet    we'll see if he still wants 10 foot of pilot house once the cuddy is built.  There is a rule of 1/3's that helps make things look right but it's all fun and games laying this stuff out.  I enjoy it.

[Brian.Dixon]

Thanks for the advice Brian.  The plan right now is for the generator and 2 house batteries at the transom.  Below deck he would like 2 ea 100 gal fuel tanks that will start about 12" forward of the transom going forward, then a small water tank.  (I've not calculated if there's enough room for both fuel tanks to be 100 gallons).  I think 150 gallons of fuel would be plenty and expect at least 3 nm / gal from this boat at cruise.  It'll be powered with a pair of 2007 mercury 4 stroke 150's that have 100 hours on them.  They've been pretty much pickled and appear brand new. 

There will also be 3 batteries for the spot lock trolling motor somewhere midship to forward up to the front pilothouse bulkhead.

I've put a lot of hours on my 27' Jumbo and believe your advice to be perfect for someone building a Tolman also.  I've noticed a huge difference in fuel mileage and performance by making small changes like moving a 100 pound life raft from the cuddy to around station 6 in the pilot house.  I know you made a completely new plan for the GA, but there are enough similarities between them in construction material, weight, etc.  I made many trips offshore in the NE Atlantic with a 500 pound tuna cooler sitting 3 foot forward of the transom and an extra 300 pounds of jerry can fuel in the pilothouse.  (LOL... those were the 2 stroke days as there was already 87 gallons of fuel in under deck.  ha ha)

Sounds good, although the 3 batteries in the house, possibly as far forward as the forward house/aft cuddy bulkhead might be weight you could keep closer to the aft house bulkhead.  And as far as boat similarities go, I was and am very impressed with the structural design of the Tolman, and that's why I used it (with Renn Tolman's explicit written permission) on the GA ... if something's optimal, then it's optimal ... don't reinvent the wheel.  And also, all planing hulls are very similar on where the center of gravity goes, and that impacts loading decisions.  Unlike a displacement vessel, planing hulls have a list of requirements that make them able to skim across the water efficiently ... more akin to an aircraft needing to be balanced perfectly versus a car rolling down the highway that can be loaded pretty much any way you want ... not so on airplanes and planing hulls.  Two thirds of a planing hull is forward of the center of gravity, and like a teeter totter, you must pay attention to loading in order to keep things balanced and operating optimally.

[cj8mule]

Those 3 batteries are for the spot lock trolling motor and need to stay together.  Maybe we could place them near the rear pilot house bulkhead on starboard side and then counter that weight with a tackle station on the port side.  I'm thinking those 3 batteries weigh over 150 pounds, so it's significant enough to think about it.  If Jake's anything like me, The tackle station ends up carrying at least 100 pounds of just lead weights.  lol

[Brian.Dixon]

I agree.  Putting those 3 batteries at the aft pilothouse bulkhead would be fine.  The CG on a 28 foot boat is around 9-1/2 feet forward of the transom or so.  Weight aft of the CG encourages bow-up trim and vice versa for weights forward of the CG.  And the further a weight is from the CG, the more impact it has.  Example) 150# located 10 feet forward of the CG creates a 1500# moment-arm that encourages bow-down trim.  If you tried to balance that out with a tackle area that was 5 feet aft of the CG, then the tackle area would need to weigh 300# since 300# at 5 feet aft creates a balancing 1500# bow-up trim.  Get it?  The boat is big and it's forgiving of these things, but during the planning and construction of the boat, you want to aim towards a balanced boat and then use it any way you want once it's done and your careful planning will result in a very-forgiving boat.

[cj8mule]

Some progress.

[Dan Boccia]

Interesting reading through the comments - a few things stand out to me that you might want to consider further:
1. Thinking that any Kodiak will get 3 nmpg is fantasy I think. For roundtrip averages, even regular GAs have difficulty averaging that on full trips consistently. Lindy's Kodiak, which he built heavy with lots of fancy hardwood cabinetry etc doesn't even get 2 nmpg right now with his brand new twin 175 Yamahas. So if it was me and you're building light and smart, I'd plan for no more than 2.5 nmpg and maybe even a bit less.

2. I'm curious why the generator? As an electrical designer/installer, I've now talked 3 clients out of generators and instead got them into good lithium house batteries and solar systems and they've loved that setup universally. The Kodiak has tons of roof space for solar panels.

3. House batteries way back at the transom sounds like an awful lot of weight/congestion back there, especially with twins, plus larger cable sizes needed to get to the main helm panel. Plus that takes space where you might want a washdown pump, bilge blower, final negative/ground/bonding bus, start batteries, fuel system parts like water separator, valves, etc. etc. My favorite place for batteries is just aft or just forward (in the case of lithium) of the aft cabin bulkhead. This puts them closer to the CG of the boat and in a convenient place for wire runs.

Keep up the good work, this is a fun one to watch!

[Brian.Dixon]

Using twins (Lindy) will always use more fuel than using a bigger single - Twins are primarily an insurance plan.  If one motor fails, you've got a second one of healthy size to get you back with - much better than going 100 miles back on a 15 hp kicker ... in a zone with no towing services.  The highest mileage option is a sterndrive, and second highest is a single outboard, multiple outboards come in last - but is the only option that gives you extra safety via redundancy.  The boat's displacement, weight, is the largest factor affecting mileage.  Being properly balanced around the CG is the next thing.  Hull form next (including defects such as humps and hollows). Then parasitic drag such as bottom roughness, skegs and keels, hardware, the leg on outboards etc.

Brian

[cj8mule]

Interesting reading through the comments - a few things stand out to me that you might want to consider further:
1. Thinking that any Kodiak will get 3 nmpg is fantasy I think. For roundtrip averages, even regular GAs have difficulty averaging that on full trips consistently. Lindy's Kodiak, which he built heavy with lots of fancy hardwood cabinetry etc doesn't even get 2 nmpg right now with his brand new twin 175 Yamahas. So if it was me and you're building light and smart, I'd plan for no more than 2.5 nmpg and maybe even a bit less.

2. I'm curious why the generator? As an electrical designer/installer, I've now talked 3 clients out of generators and instead got them into good lithium house batteries and solar systems and they've loved that setup universally. The Kodiak has tons of roof space for solar panels.

3. House batteries way back at the transom sounds like an awful lot of weight/congestion back there, especially with twins, plus larger cable sizes needed to get to the main helm panel. Plus that takes space where you might want a washdown pump, bilge blower, final negative/ground/bonding bus, start batteries, fuel system parts like water separator, valves, etc. etc. My favorite place for batteries is just aft or just forward (in the case of lithium) of the aft cabin bulkhead. This puts them closer to the CG of the boat and in a convenient place for wire runs.

Keep up the good work, this is a fun one to watch!

Jake is wanting to pack a lot of things in this Kodiak.  He's putting on a spot lock trolling motor that will use 3 batteries and then the other 2 house batteries.  I don't think I'll be able to talk him out of the generator.

To be honest if he gets 1.5 to 2 nmpg he'll be happy.  This boat keeps getting heavier and heavier.  Enough so we're going to need to be very careful with where stuff is going to go. 

I don't think I mentioned it before, but I'm preparing for an anti roll gyro that weighs 286 pounds.  If anything needs to go at the center pivot point, this thing does.  It is going to be interesting calculating all this stuff out for a good CG.

[cj8mule]

Working on the cuddy is one of my least favorite areas...  knee knockers, head knockers...  and just a general pain.   

[json]

I am really interested to see your sea keeper integration if you do go that route. That was on my list but I eventually tossed it to just keep things a bit more simple. Also going to be interesting to watch the weight distribution. That problem is a bit of a thorn in my side that I am still working out.

[Grady300]

Using twins (Lindy) will always use more fuel than using a bigger single - Twins are primarily an insurance plan.  If one motor fails, you've got a second one of healthy size to get you back with - much better than going 100 miles back on a 15 hp kicker ... in a zone with no towing services.  The highest mileage option is a sterndrive, and second highest is a single outboard, multiple outboards come in last - but is the only option that gives you extra safety via redundancy.  The boat's displacement, weight, is the largest factor affecting mileage.  Being properly balanced around the CG is the next thing.  Hull form next (including defects such as humps and hollows). Then parasitic drag such as bottom roughness, skegs and keels, hardware, the leg on outboards etc.

Brian

Yes I LOVE my twins, already came home on one motor once. Just clogs in fuel filter but non the less my single brought me home!!! yes of course I had extra filters on board but I wasn't sure on the problem till the next day. Yes I burn more fuel, but well worth it for me anyway. Besides Twins look Bad Ass!! My normal cruse to the fishing grounds loaded up with ice, all gear, full 60 gallon bait tank & 160 gal fuel 21-23 mph @ 2.1 to 2.4 MPG depending on seas. Not bad for a 31.6' Kodiak. Love my GA !!!!

[Brian.Dixon]

Pretty impressive performance, Chuck!  It really is, especially with twins!

For the rest of the crowd as you ponder power solutions ... note that the term "inshore" generally refers to operation within around 20 miles of a suitable port, while "offshore" is anything further out than that.  Some define "offshore" as being "off soundings", which in turn basically means your depth finder (or fish finder) is not returning any depth information because the bottom is too far down and too much sonar loss is occurring.  Anyway, I ramble ... I just wanted to state the general rule of thumb that if you operate in inshore conditions, mostly, a single and a kicker is recommended.  If you operate offshore, mostly, then twins is generally recommended. 

[cj8mule]

Bringing the cuddy area home.  Ready for some sanding and paint then the roof can go on.













The anchor well has a fiberglass tube drain for the starboard  side....  Always hate cutting holes in boats.  lol

[Brian.Dixon]

I hate cutting holes in boats ... near or below the waterline.  The whole top of the hull is a big ol' hole ... it's just further from the water!