Reducing boat weight

[Nick in the TC]

      Reading the other thread about reducing weight in the rear end of the boat has got me thinking. I have a 2012 Response CB and love the wake. I ski at 28-35 off at 34 mph and love it but have a 10 year old son and his wake at 28 mph could be a little better.

      I am thinking it wouldn’t be to hard to drop 200# or so behind the motor but my biggest question is how many have moved the fuel tank into the nose of the boat?  Would there be any more of a hazard having the tank in a closed bow vs under a floor or in the far back?

[Eagleboy99]

200 lbs is more than a full tank.  Take the kid out with 5-10 gallons in it.  We rarely have a full tank (RLx)

[justgary]

I'm just curious, and not trying to talk you out of anything, but you didn't say if your son is competitive or just skiing.  Either way, making the wake too easy for him might be counterproductive in the long run.  A response wake isn't that big anyway (and I ski behind one often, at 29 mph). 

The other thing I'll mention (as an empty nester) is that he will probably be with you in the future for less time than he already has been.  Don't do anything to your boat that will put it out of commission when he's ready to ski with you.  In a few years you may have to beg him to go with you, so enjoy every minute you can with him.  He won't be 10 very long....

That said, I think moving the tank should be pretty simple.  Adding a fill port though the deck will be the reason you might pause.  

[Nick in the TC]

    We always ski with 3/8 of a tank or less but how much gas is really in there?  Yea the lake will be “out of commission” for the next 6 months so no lost time on the water. My son has just started slaloming on a regular basis and is improving quickly, he is pretty athletic. 

    I have thought about drilling a hole for the new fill hose and I think I am OK with that. Also would have to do one for the fill/breather line. 

Getting rid of the rear back rest, hatch/compartment, and tank would be quite a bit of weight and I think I could make a new platform easily that would be 1/2 the weight of the stock one. 

[ahopkins22LSV]

@Woodski moved his tank to the bow in his echelon. 

[Nick in the TC]

Yea I saw @Woodski his was moved to the ski locker in between driver and passenger seat. 

[UWSkier]

Do you run any bow weight currently?  Is the boat pretty well leveled when he's out there skiing?  I know MN is a no-spotter state so are you counterweighting?

[Nick in the TC]

Yes I have about #75+ In the nose and battery is all the way to the passenger side. More just bored and need some kind of project. 

[UWSkier]

35 minutes ago, Nick in the TC said:

Yes I have about #75+ In the nose and battery is all the way to the passenger side. More just bored and need some kind of project. 

I lived in WI for 38 years... I know what you mean about winter projects! 

[Chaabo]

Interesting thread.

Whatever you end up doing/modifying, take into consideration that you don’t want the back of your boat to be too light while you focus on weight reduction to optimize the wakes. A too light back will dramatically loosen the tail of the boat and will make it hard for the driver to compensate for skier’s pull and keeping a straight path and a tight line for the skier through the course.

Some “less drastic/intrusive” ideas I can think of ...

Get rid of the HDS box that fills up with water as soon as the boat hits the lake. Install a shaft log and seal the box. The HDS box holds approximately 6 Gallons of water. That’s about 50 pounds of weight right there!

The carpeted floor piece on top of the fuel tank in the trunk is made of that pretty heavy black HDPE stuff and weights a ton. I ripped that out, used it as a template and cut a super lightweight honeycomb style board to fit in the trunk. Transferred the carpet and saved another (guessed) 25 pounds in the back of my boat.

Whatever you do, keep us posted. I think everyone here likes to see these kinds of projects! 

[smileysteve]

15 hours ago, Nick in the TC said:

Would there be any more of a hazard having the tank in a closed bow vs under a floor or in the far back?

This was standard with closed bows for the longest time. (I had a 1972 searay closed bow with fuel tank under bow and fill on the bow.

 

14 hours ago, justgary said:

Either way, making the wake too easy for him might be counterproductive in the long run.

I agree with this, especially when it comes to removing the platform or making a new one lighter. All promo boats are going to have a platform on them for competitions.

And, I'm not sure I'd optimize for the battery to the outside either; the goal should be to balance the driver; but with the added understanding that tournament boats are often driven with a radio assistance, and sometimes an extra; and have optional weight to balance the driver.

42 minutes ago, Nick in the TC said:

More just bored and need some kind of project. 

A fun project re the battery could also be to mount it at least semi "sub floor", lower that center of gravity for more tracking and less sway.

[Nick in the TC]

I don’t plan on entering many tournaments this is just for fun. I also hate stepping over the rear trunk and really don’t have a use for it. Eventually the trunk pad will just get scratched up and be the first vinyl to start showing signs of wear. 

The battery is in the stock location from what I understand. 

[Eagleboy99]

12 minutes ago, Nick in the TC said:

the rear trunk and really don’t have a use for it.

And replace it with what?  The sunpad/trunk on my 99 RLX weighs maybe 25 lbs?  maybe.

[Eagleboy99]

Another that just hit me:  what line length is your kid skiing at?  One of mine skis at about 28-29 but we use a shorter line as the wake is less closer in.

[Chaabo]

An issue you are running into when removing the gas tank completely - the floor carpet is cut off somewhere right in the middle below the tank. So you will be left with just a bare (and not very pretty) gelcoat floor. And be prepared for a stinky mess underneath the tank. 

(I happen to know how these boats are put together, because I prepared one of my Responses for a direct injection LPG conversion in which the gas tank was eliminated and replaced with a built-in cylinder- shaped LPG tank.)

[Nick in the TC]

I will probably be looking more into it this weekend but one thing you said @Chaabo I assumed the carpet would go all the way to the back and not stop half way under the fuel tank.   I will have to check that out. 

[UWSkier]

Just now, Nick in the TC said:

I will probably be looking more into it this weekend but one thing you said @Chaabo I assumed the carpet would go all the way to the back and not stop half way under the fuel tank.   I will have to check that out. 

Yep.  Pull up the removable floor panel and you'll see the gas tank kindof hangs there in space.  There isn't floor all the way to the stern.  Also, behind the rear wall panel for the trunk is not finished glass all the way to the floor.  You'll have a bunch of unfinished surface to figure out how to address if you remove the rear setup.

[Nick in the TC]

Yea I knew the floor panel didn’t go all the way back. Covering up unfinished fiberglass won’t be in issue. 

[Chaabo]

@Nick in the TC if you PM me your email address, I can send you a bunch of pictures of how it all looks with the tank/seat/trunk/panels removed. Should give you a pretty good idea of what you are facing.

[justgary]

6 hours ago, Nick in the TC said:

More just bored and need some kind of project. 

"Oh.  Well, that's very different.  Nevermind."

- Emily Litella

[Wayne]

Does your boat have a wedge bracket? I run a scarpa suppression plate for people that ski at lower speeds and it helps knock the wake down. 

[Nick in the TC]

No wedge plate.  This boat is bare bones not even radio or speakers. I have read mixed reviews about the scarps plate but being I don’t have the wedge bracket that really isn’t an option. 

@Eagleboy99 the wake is really bad at full line 28 mph so my boy was skiing 15 off. By bad I mean big nasty trough in between the wakes

[Eagleboy99]

Start them young on shortline.

[Nick in the TC]

He man handles the mini course behind the fishing boat. 

[SkiPablo]

2 hours ago, Nick in the TC said:

No wedge plate.  This boat is bare bones not even radio or speakers. I have read mixed reviews about the scarps plate but being I don’t have the wedge bracket that really isn’t an option. 

@Eagleboy99 the wake is really bad at full line 28 mph so my boy was skiing 15 off. By bad I mean big nasty trough in between the wakes

my boys ski 28 and 15 off and it's great - I would think your boat would be similar, maybe you are being too picky ?