Romsey Sub-Aqua Club

Wreck Diving

RomseySAC is located in South Hampshire and dives the Hampshire and Dorset Coast, this means we have an incredible resource of "local knowledge". RomseySAC do a range of diving including Shore, RIB and Hard-boat diving. RIB diving is normally the hardest for a club to organise, with boat preparation, dive planning, and kit preparation. So we have tried our best to reduce the effort of dive preparation by publishing our GPS Co-ordinates, Depths and Slackwater times for some 270 possible wreck sites.

There are a lot of new sites being discovered on the South coast and so diving in the range of 10 Metres to 40 Metres has never been better. See the Charts included on this page.

RIB Diving

We would like to encourage club RIB diving, and therefore have tailored these co-ordinates to RIB diving. If you or your club does not have access to a RIB, there are many hard-boat skippers able to take you out to these sites. These hard-boat skippers offer an excellent service in this area. There are boats leaving from Portland, Weymouth, Swanage, Lymington, Portsmouth and Selsey Bill.

Co-ordinate coverage

These wreck co-ordinates have been produced with the following criteria:

1. Lie between: W003Deg and W000Deg 30Mins.
2. Within 12 miles of a RIB launch site.
3. Less than ~40 metres in depth.
4. Greater than ~5 metres in depth.
5. Excluding the Solent, Rivers, Deep-Draft Anchorages and Shipping Channels

Wreck Coordinates

There are 270 co-ordinates on six PDF formatted pages that can be printed out. The copy and paste function has been disabled within the PDF file to help preserve copyright.

RomseySAC co-ordinates are in the form:

RomseySAC asks for a donation, with minimum of ~£15. A lot of work, local knowledge, and expense has been gone into producing these dive planning guides. If you do not wish to donate for wreck, depth or slack information from RomseySAC, there are many other website providing free co-ordinates. RomseySAC has found the following resources useful, and thank the following sites of publishing their work.

• Angel Fire
• Caversham Park Aquanauts
• Chippenham Divers
• Wreck Site
• Diver Magazine: Wreck Tours and 100 Best Wrecks.

Disclaimer

RomseySAC is provides these co-ordinates without guarantees of accuracy in terms of name, location, depth or time. We have provided them to the best of our knowledge, and the information can be found within our club's own GPS. It is always prudent to obtained the name, location, depth and slackwater from a secondary independent source before diving.

Price

RomseySAC co-ordinates are not free, and not for distribution on other websites. Written permission from a RomseySAC committee member must be sort for the reproduction of these co-ordinates. We would expect a ~£15 donation that goes towards club funds (which includes the Paypal charges).

RomseySAC is a non-profit making organisation, and are a part of BSAC (Club 1259). Any donations will be used for equipment, services and maintenance. Our engine is on it last-legs, and so we are saving-up so we can continue to dive into the future.

Once you have successfully donated, you will be directed to a webpage with co-ordinate links; usernames and passwords

If you should have any problems then please contact: Steven@RomseySAC.com

The co-ordinate pages are very distinctive, and as we're out most weekends, we welcome feedback an so we may tap you on your shoulder to find out how successful they are.   Suggestions and updates via the above email address are most welcome.

A Guide to the Database

The information falls into 4 parts:

1) GPS Name

This has been shorten to a maximum of 6 alphanumeric characters, so that it can be placed into a GPS. Please refer to this unique name in any correspondence

2) Waypoint

Co-ordinates are given in WGS84

This is primarily a Cardinal; Degree; Minute and decimal Minute (to 3 places). These waypoint have been gathered from a number of sources and overlayed on the latest charts to verify their approximate position.

We have included a number of unknown sites and last known positions; and therefore some searching may be required in the dive area. Some wrecks may just not be there!

3) Depth

These depths are approximate, the seabed changes and wreck scour out holes around the bow/stern. In addition, the tide can have a range typically +1 Metre to + 4 Metres on top of chart datum. Therefore, be aware of this when gas planning.

4) Slack water time

This is the hard bit, and RomseySAC has come up with the most comprehensive slack water calculations on the internet.

We have used PORTLAND as our reference port and hence recommend the UK Hydrographic Office's website for tidal calculations.

We have calculated the Slackwater in periods of 10 minutes.

We have calculated slacks for both NEAPs and SPRINGs. NEAPs and SPRING tides are normally 2-3 days after the respective Moon phase in the Channel. You can estimate a ratio of your dive date, between the Neap and Springs of that month. Hence obtaining a greater accuracy for Slack water. Slack water can be different by 2 hours based upon Neaps and Springs.

Remember, surface air pressure has a great effect on the tidal height and hence slackwater period and therefore you need to arrive on the dive site earlier than these times to judge accurately when slackwater occurs. It is also worth looking at the actual tidal heights as this will give a more accurate indication or and advanced or retarded slack.

In all instances please report any errors found.

Tide Information

Please refer to the following locations:

• Reeds Nautical Almanac
• Admiralty Website.
• Portman Oceanographic Website.
• Wxtide32, see our software page.

Feedback

When using co-ordinates be very careful in handling them especially through a number of software programs that have a tendency to round up and down. Error is introduced very easily.

Error is caused by

• OSGB36 to WGS84 conversion (to 200 metres on the South Coast)
• Errors on charts, definitely not to be trusted, could be up to 0.3 of a mile
• Decimal place errors: the format DD MM.M meant the minutes are to 1 decimal place. This introduces and error of ~260 Metres (the hypotenuse of 185.2)
• Selective Availability (SA), co-ordinates before 1^st May 2000 will have ~150 Metres of error. After this date error will be ~10 Metres without WAAS/DGPS.
• Human error, i.e. getting the number wrong way around. This has happened in official government records

This means that if a person that give you a 1 decimal place wreck co-ordinate, who is adamant he was sat over the wreck, could in fact give you a location over 1 mile away when you compound all the errors.

Therefore, consider a RomseySAC rule of thumb.

• Co-ordinates to 1 decimal place mean that you need a gps and side-scan sonar (~£10k).
• Co-ordinates to 2 decimal places you need a gps and photon magnetometer (~£5k)
• Co-ordinates to 3 decimal places you can use a gps/sounder (~£1k)

If you have any high quality co-ordinates please report them to RomseySAC via the information button

Coordinated need to be presented in the following format

Aeolian Sky Stern

GPS, Diff, SA off, WGS84, DD MM.MMM, N50 30.595 W002 08.423

Aeolian Sky Bow

GPS, Diff, SA off, WGS84, DD MM.MMM, N50 30.563 W002 08.423