How Much Reliance on Dive Shop Planning?

[stephen1254]

We are both newly certified with 8 logged dives apiece. We are both very comfortable in the water.

While we have really enjoyed our diving so far, we realistically know there is a limit as to how much diving we can do - likely 20 dives (20 tanks) or so a year, mostly on day trips from cruise ships in the Caribbean. We have our own mask, fins, and snorkel, but beyond that we have elected to not purchase any equipment for now, until we have a better idea of what we like and don't like.

We are going in May to Tortola, and planning a dive on the RMS Rhone. We discussed this dive with our instructor - we were in St. John - and he encouraged us to do the dive, and felt we were qualified. We have no qualms as to our qualifications. We are going with a company that has been leading dives to the wreck for over 40 years, and does them twice a week.

My specific question is whether I should invest in a dive computer. What I have now is a PADI eRDP. When I plug in the planned dive times, depths, and surface intervals, I come perilously close to the limits of a no decompression dive. I recognize that the planner is conservative, and doesn't account for being at different depths for different periods during the dive. A dive computer would take that into account.

My wife suggests that the dive shop operator knows what he's doing, will build in a safety margin, and will not take a chance on someone being down too deep for too long. As far as we can tell, he has an excellent track record. I'm still wondering if we should have a computer as backup.

I recognize completely that we are responsible for our own safety, and the safest thing to do would be to have our own computer (and likely our own gear that we are completely familiar with). On the other hand, I recognize that the dive shop doesn't want to take a chance. I'd rather not buy a computer if I don't have to right now. What say you all?

 

[Marie13]

Get the computer. They're cheap enough now that there's no reason NOT to have one.

 

[ScubaWithTurk]

We are both newly certified with 8 logged dives apiece. We are both very comfortable in the water.

While we have really enjoyed our diving so far, we realistically know there is a limit as to how much diving we can do - likely 20 dives (20 tanks) or so a year, mostly on day trips from cruise ships in the Caribbean. We have our own mask, fins, and snorkel, but beyond that we have elected to not purchase any equipment for now, until we have a better idea of what we like and don't like.

We are going in May to Tortola, and planning a dive on the RMS Rhone. We discussed this dive with our instructor - we were in St. John - and he encouraged us to do the dive, and felt we were qualified. We have no qualms as to our qualifications. We are going with a company that has been leading dives to the wreck for over 40 years, and does them twice a week.

My specific question is whether I should invest in a dive computer. What I have now is a PADI eRDP. When I plug in the planned dive times, depths, and surface intervals, I come perilously close to the limits of a no decompression dive. I recognize that the planner is conservative, and doesn't account for being at different depths for different periods during the dive. A dive computer would take that into account.

My wife suggests that the dive shop operator knows what he's doing, will build in a safety margin, and will not take a chance on someone being down too deep for too long. As far as we can tell, he has an excellent track record. I'm still wondering if we should have a computer as backup.

I recognize completely that we are responsible for our own safety, and the safest thing to do would be to have our own computer (and likely our own gear that we are completely familiar with). On the other hand, I recognize that the dive shop doesn't want to take a chance. I'd rather not buy a computer if I don't have to right now. What say you all?

It is up to YOU to plan your dive and dive your plan. Sure shops will take you out on dives and tell you your max depth, bottom time, etc but if there is one thing I have learned from being here on SB it is that the responsibility to dive safely is up to me.

But with logged dives, I am not sure a wreck dive is the smartest but I suppose that depends on the depth of the wreck and many other factors.

 

[Marie13]

Puck Pro - Dive Computers - Dive Computers - Computers & Gauges - ALL SCUBA GEAR - Dive Right in Scuba

Something basic like the Mares Puck Pro for $240 on www.diverightinscuba.com would work for you. It even does nitrox if you'll eventually do that.

 

[2airishuman]

Common question.

I bought a computer. I'm buying computers for my kids, who are new divers. You need to be able to measure the passage of time, and you need to be able to measure depth. A computer is the best and cheapest way to do this.

They also will allow you to determine your NDLs more accurately, which will become important when you start making deeper dives.

 

[Marie13]

OP, I have to ask. If you live in FL, why aren't you doing any local diving?

 

[Lorenzoid]

Others have given good advice.

You clearly understand why you should have a computer. The tables aren't optimal for the kind of diving you're doing. Sometimes, the boat doesn't even know what site they're going to visit, and thus the depth for your planning purposes, until minutes before they arrive. That's no time to be fumbling with tables. You're supposed to be enjoying your vacation. With a computer in its dive planning mode, you can plug in the maximum depth and immediately see what your NDL will be, so you have an idea of how many minutes you can stay at that depth and plan from there. The dive planning mode that most computers offer is under-utilized by casual vacation-type divers, but it's a fine way to stick to the maxim "plan your dive, and dive your plan."

You don't really want to be "that guy" on the boat who doesn't have a computer.

 

[BoltSnap]

Get the computer. They're cheap enough now that there's no reason NOT to have one.

What she said!!

Skip a couple of meals and you will save money for the computer!!

 

[stephen1254]

OP, I have to ask. If you live in FL, why aren't you doing any local diving?

We will do some local diving, but between work and other activities the number of times we will get out is still limited.

 

[doctormike]

What I have now is a PADI eRDP. When I plug in the planned dive times, depths, and surface intervals, I come perilously close to the limits of a no decompression dive.

You are responsible for planning your dives at this point. Whether or not you have a computer has no impact on that responsibility. So there is no "perilously close", you simply adjust your dive time so that you are as far away from your NDL as you like.

You need to measure time and depth somehow, and it's fine to use the eRDP or printed tables to calculate your allowable time at depth. You still need to rent or buy some sort of timing device and depth gauge. You could use a waterproof watch if the regulator that you rent comes with a depth gague in the console.

A computer is by far the most convenient (and probably cheapest) way of getting both of those in one instrument, and it also has the advantage of calculating your actual nitrogen loading, giving you "credit" for time spent above your maximum depth. So that way, you will find that you might not be as close to NDLs as you though when working with the tables/eRDP. But if you are on a VERY tight budget, get a cheap dive watch and do a shorter dive than you would do with a computer.