How to modify..

Soren Thomsen

Hi all,

if one were to rebuild/modify and old Inspo Classic how would you go about it?
1. Hammerhead, Shearwater or ? I like the Hammerhead because of its "clean" head, especially the newest version with HUD and metalhousing. Any comments or ideas

2. BOV - Golem or other ?

3. Scrubber - standard or ?

4. Gasblock or not? what type?

5. CL - standard or modified back mounted?

6. Anything...?

Looking forward to any replies

Soren

jhaaja

First thing I would get would be the BOV.

Doorduijn, Niels

To answer your questions, let me start by saying I would not make all that much changes to an Inspo as the unit works quite well in my view.
Ad 1. Electronics: assuming properly working handsets, you need to think why you want to change it. Do you want internal decompression software or just something which is more out of the way than the standard handsets? For me, internal deco software is not worth spending much money on. I have a VR3 which I use without connection to the rebreather, for fun dives. For more challenging dives I use tables. I do not find the handsets to be a problem. Given recent stories about Hammerheads, the only replacement software which I would consider (if any and in a year or so) is the Vision software. The added value, in my view, is limited.

Ad 2. BOV. There is something to be said about a BOV, but there are also some arguments against it. I wrote an elaborate posting on that earlier this year. If you were to consider it, APD is in the process of manufacturing a BOV, so waiting for that makes sense.

Ad. 3. Changing the scrubber? Don't.

Ad 4. Gasblock: not an issue before you do very big dives on the unit and even than you need to think about it. Moreover, if you want to do diluent switches, an easier option is to plug your off board dilluent into the injection on the counterlung.

Ad 5. I cannot comment on the back mounted counterlung on an Inspo. Paul worked on that (see his earlier postings). My other rebreather is a MK 15.5, and I can see why you would want back mounted counterlungs, but the changes to the unit are rather significant, so again not something to do early on.

Ad. 6. Other changes? If you look around, you will see that the most common change is a backplate and normal webbing instead of the crappy APD harnass.

That being said and on the risk of sounding like an old geezer, there is too much emphasis on the internet on making alterations to stock rebreathers. In most cases, you are more likely to introduce new problems than to solve major issues. None of the possible changes which you mentioned are - in my view - a great improvement over a stock unit, with perhaps the expection of the BOV (leaving aside the back mounted counterlungs as I have no views on that) My recommendation is to get a lot of experience on the unit before making any changes.

Rgs,

Niels Doorduijn

Mark Chase

After a couple of years of alterations I honestly think i am close on getting it right. Some of the ideas need to be implemented but its nearly there.


Listed in terms of importance to me

1: HUD without question the single most important MOD

2: BOV. I have a V4tec plumed into off board gas

3: Classic replaced with Hammer Head controller

4: Off board cell monitoring. Was 1 cell on VR3 now 3 on the Shearwater

5: Lightweight frame Travel frame and a MH Alibox for UK diving accepting a range of cylinders

6: Backplate and adjustable harness

7: Modified 02 feed with switching block to isolate the solenoid (WIP)

8: Replacement wing with more lift

9: Replacement counter lungs which are minimum volume and more compact

10: Replacement 02 and Diluent gages.



So basically all i have left of my Classic is a few hoses, a manifold, the loop minus the mouthpiece, a scrubber and housing and the original ADV

In other words I kept all the good bits.

ATB

Mark Chase

__________________
See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!!

Kevin Juergensen 16/11/08
[/quote]

Soren Thomsen

I agree with you on that one...

But would you/anyone also change the head. I´ve had issues with the batterycompartment on a borrowed Inspo and read many stories about the electronics on the Classic - cracked, brown circiuts, no watchdog ect., and I like the idea of having HUD, deco-software and "outboard" normal batteries. In my view the Hammerhead has all that.

Soren Thomsen

I agree with you on that one...

But would you/anyone also change the head. I´ve had issues with the batterycompartment on a borrowed Inspo and read many stories about the electronics on the Classic - cracked, brown circiuts, no watchdog ect., and I like the idea of having HUD, deco-software and "outboard" normal batteries. In my view the Hammerhead has all that.

Soren

Soren Thomsen

I've read both posts
Niels: I agree that I need to do many hours on a unit before altering anything. Well perhaps not the BOV. The reason why I - remember I'm a greenie - could consider changin the head is because of what I've read. I already have a VR3 so monitoring one cell should be a fairly easy process. This however leeds me to the following: Monitoring one cell isn't enough, all 3 cells should be monitored by the computer that calculates my deco ect. What kind of problems does the Hammerhead has or have had?

Mark: I guess that you and I think similar on this based on you're reply. Have you had any issues with your Hammerhead?

Soren

Mark Chase

Hi Soren

The HH is very good but it has a couple of issues which hopefully we now have the answers for. I have the latest spec unit.

These are mainly related to the new Aluminum hand sets. The Battery caps are stainless steel but the threads in the hand sets are Aluminum. As a result oxidation on the threads causes poor contact with the battery cap and intermittent contact quality under load. This for some reason is made worse by depth.

The problem is now known and steps have been taken to fix it.

1: the threads are made rough to bite into the layer of oxidation and provide cleaner contact.

2: Conductive grease is use to full the voids between thread on the body and the cap and make the best of any available contact areas.

3: Anti oxidant coatings are being used to prevent the initial Oxidation.

If these steps work the major problems of the system rebooting during a dive are gone.

Recent upgrades to the depth sensor and the wet sensors have fixed problems with units that would not switch off and hopefully this will reduce the drain on batteries and ultimately battery usage.

The master controller can not be switched off in water so if you do get
rebooting of the hand set you will suffer from big 02 spikes as it test fires the solenoid. As a result some form of system is needed to let you run the unit manually and switch off the 02 to the solenoid or you need to bailout.

The unit eats batteries I would generally throw away the battery in the primary after a days diving. However AAs are cheep and the mods may stop the need for this.

Minor irritations include. Bulky hand sets slipping around on your wrist and a scrolling main display thats never on PP02 when you want to check your PP02.


On the up side its a lovely head to work with and when its working correctly it is a pleasure to dive. The controls are intuitive and well thought out and the Gradient Factor Deco is very easy to use.

The range of functions is excellent and KJ has a very good reputation for electronics so i have more faith in the circuits than i do with the AP stuff.

To deal with KJ is very much a human being rather than a MD of a company and that has up and down sides to it, but I personally rather like him.

My personal reason for going HH rather than Vision was i could afford to get two HH units and have a spare. I view the HH as miles and miles better than the Classic and at least as good as the Vision.


HTH

Mark Chase

__________________
See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!!

Kevin Juergensen 16/11/08
[/quote]

Russ

I would start with the cheap and non invasive mods first
1) Add a backplate and harness
2) Replace inflator with a standard one and shorten corrugated hose

As for replacing head I'm waiting for the sherwater inspo. head as they have a HUD I like

I think a bov is literally a lifesaver but I'm also waiting for a new bov to come to the market as I think the golem is very expensive and rather large for my tastes

everyone seems to really like the travel frames but for me I'm not going anywhere soon by anything other than boat/car but maybe I will purchase one in the future

Russ

pchanning

Agreed. It is a significant change. Get the hours up first and really learn to hate those clumsy, constricting CL that are invariably in the way. It will make the transition all the sweeter

Anyhoo... IMHO get a BOV with a good quality 2nd stage and a gag strap. You wont go far wrong.

My Inspo is a bit like Triggers broom from Only Fools and Horses (a quirky staple UK comedy series)... had it for years that broom... its had 10 different heads and 14 different handles...

Seasons Greetings

__________________
Cheers
Paul

The key to enlightenment... is survival.