7 metre.. suggestions for deck layout

[Todd Grimley]

Hoping I can get a little feedback. Changing to outboard on this old Otech and looking for suggestions on best deck layout!
Planning on doing some chopping and changing. Hope to make the rear compartment into a rear bench seat and move console forward enough to put a free standing leaning post at the console and have a bit of room to move around and fish off the back.
How far forward to move the console is the best ride with an outboard. There is a 250 litre fuel tank going where the inboard was.
Thinking of cutting the old engine cover back to make a normal size seat in front of console.
Any suggestions welcome.
Cheers Todd

[Xk59D]

Probably not ideal to have a fuel tank that far back along with an outboard or 2 hanging off the back along with a bench If starting afresh.

If you are moving things I would be wanting the tank further forward along with the console.

[Maximus]

Originally Posted by Xk59D

Probably not ideal to have a fuel tank that far back along with an outboard or 2 hanging off the back along with a bench If starting afresh.

If you are moving things I would be wanting the tank further forward along with the console.

I would agree especially about the Fuel Tank! (Where is it now?)...Nearly 400ib of Fuel and seating located at the Stern in turn combined with a Big Hefty Outboard could well ruin performance...unless you want to start competitive ploughing
All wants moving forward IMO ...and careful consideration.
Best bet is find someone who has done it before...and learn by their mistakes/learning curve

[jwalker]

Yeh, I'd be thinking along the lines of Xk59D. Put the fuel tank approximately midships, especially since the previous engine has been there and the hull is likely to be ok at carrying weight in that position. Also, you've got a big hole there already so it should be reasonably straightforward for fitting the tank.

The space behind your new rear seat can be converted to storage if you're inventive in mounting the outboard.

The further forward the console, the rougher the ride will be so you'll have to balance that with useful deck space to suit your own preferences. However, if you don't travel with many crew, putting the tank right forward and the console as far rear as is practicable will give you best ride and also a large forward deck space. You appear to have something at the bow, if this is a large locker, putting heavy items there will allow you to balance the boat to some extent if that proves necessary.

[ncp]

Look up the build by bigtalljv. I think he got 60 gallons or so in the original fuel tank location and kept the console/engine area for storage.

[Bigtalljv]

Yeah I think I got 63 gallons or so and there might have been room for a little more. Mine’s an old zodiac so the layouts a little different. The stock diesel tank was just forward of the console. I removed the rear box and cut the front off the console to make a seat. I wouldn’t put a bench in the back, these boats don’t have that much space when you get right to it. The tubes make great seats when at rest and beanbags are awesome for in motion. Then you throw them up on the t-top.

[Todd Grimley]

Thanks for the suggestions! Probably didn't tell the whole story first up! The original fuel tank which is about 36 US Gals. will stay in the same position which is as far forward as it can be , and the new fuel tank (250 L) will be mounted right behind it . As the original cummins was mounted mid ship, I will be using the old engine mounting plates to fasten the tank to it.
Do you think that it will ride ok with that weight there and a full flotation pod carrying 250hp Yamaha?
With that amount of fuel/weight would it really make too much difference where the console is?
I have got a lot of inspiration from your build Bigtalljv! How far from the inside of the transom is the console now mounted on you boat ? Are you happy with the ride or do you think you could use more weight up front or mid ship?

The pictures are the 2 tanks and where the yellow tape is, is approximately where they'll sit in the boat!Attachment 1

[Todd Grimley]

Wrong photos!
Try those.
Cheers for all the feedback, keep it coming!

[jwalker]

You should have told us that in the first place!

You need your tanks approximately over the centre of gravity so that as the fuel load decreases the boat stays reasonably trimmed.

[Todd Grimley]

Originally Posted by jwalker

You should have told us that in the first place!

You need your tanks approximately over the centre of gravity so that as the fuel load decreases the boat stays reasonably trimmed.

Yes, sorry once more for not giving the whole story. I'm good at that!

I will set up the fuel system to burn the rear tank first, leaving the forward tank till last. Hopefully that should keep the trim good. Rarely would need to burn that much fuel on any one run... but it is a 2 stroke!!
Basically most the fuel will be in the front half of the boat.

[jwalker]

I did say mount the tanks over the centre of gravity but when the boat is planing they are best placed over the centre of lift. It's unlikely you'll know where that is so a guesstimate is about the best you can do. It will be rear of the centre of gravity by a fair distance but obviously it depends also on the position of all your other fittings and where the folk you have on board are placed. Kinda around the 1/3 of the hull from the stern (ish). Judging from the yellow line on your picture the tanks may be a bit far forward in that position.

[Bigtalljv]

When I talked to zodiac they reminded me that the CG was where the giant diesel engine was originally mounted. Todd, I think you’ll be fine. My boat rides great and I generally have all people in the back. The back, driver location, of the console is where it was located originally, I cut the front off it. The boat is still hibernating for the winter but I’ll try to crawl under the cover and measure. I know on the official zodiac outboard versions they put an 85 gallon gas tank where the diesel used to be.

Are you doing a t-top? Plan on some wings if it’s not enclosed. Turn out fast boats in cooler weather gets real cold real quick.

[Todd Grimley]

Originally Posted by Bigtalljv

When I talked to zodiac they reminded me that the CG was where the giant diesel engine was originally mounted. Todd, I think you’ll be fine. My boat rides great and I generally have all people in the back. The back, driver location, of the console is where it was located originally, I cut the front off it. The boat is still hibernating for the winter but I’ll try to crawl under the cover and measure. I know on the official zodiac outboard versions they put an 85 gallon gas tank where the diesel used to be.

Are you doing a t-top? Plan on some wings if it’s not enclosed. Turn out fast boats in cooler weather gets real cold real quick.

Thanks Bigtalljv, the old engine bay definitely seemed like the obvious place for a large fuel tank,so I think I'm on the right track!As jwalker says I may have to distribute weight around to get trim right.
I like the idea of passengers sitting/standing toward the stern, to smooth out the ride. So I think I'm going to do as you've done and take out rear compartment and put a leaning post/seat at helm with a grab rail behind for standing passengers. Also cut back the engine cover for more deck space.

Will eventually put a t top on. I know what you mean about getting cold quick in a fast boat, I feel in love with these boats when I lived in B.C. I now live in Queensland, Australia so not such a problem Except the odd early morning winter start... but still not bad compared to the Pac. Nth. West.
I might PM you to see if I could get some more pics of your build around the stern area!
Cheers todd