Need Help Planning New Boat

Hi,

Welcome to Yacht Forums

If you can eek out 2,500 nm at 9 kts what do you estimate your range will be at the stated cruise of 18kts?

Just remember that you need to know what is usable in that 2300 gallons. You will not be able to use all 2300 gallons. so that cuts into your "reserve" right from the get-go.
Good tank design will help someof this, but bear in mind that the pickups will not be at the very bottom of the tanks, and based on tank design and baffles you will need to have some fuel above the level of the pickups so you will not suck air into your fuel system when the vessel rolls.
The best feature in the fuel system in the yacht I currently run is stripping lines, these are hoses permanently plumbed to the very bottom of the tank that can be used to easily get sludge and moisture out of the bottom of the tank.

Good advice, but the air problem can be eliminated by using a daytank I guess...?

Regarding the Air/Con here are some basics you need to consider during initial planning:

The capacity needed to air-condition a room is expressed in Btu/h. In order to calculate the value somebody must calculate the room surface of each cabin and consider its' position in the boat. This table gives the capacity value expressed in btu/h from the surface area value for tropical conditions. When more rooms are to be conditioned, the addition of each individual capacity gives the total capacity needed for the boat.

Heat load calculation
This is the name of the formula which is used to find the capacity needed to air-condition a room (cabin). The most simple formula needs the following data:
S=The floor area of the room to be conditioned.
Te= External temperature
Ti= Desired Inside temperature
K=Thermal coefficient of the room to be conditioned (there must be a K, otherwise what formula is this?)
The formula is: Heat load = S x (Te-Ti) x K.
(Te - Ti) depends from the climate somebody has to consider: Mediterranean uses officially 8-10 which is the difference somebody wants to achieve between outside and inside temperature. For tropical climates the standard used value is 15.
Finally we get to K:
K value is determined by the solar gain, the quantity of people and the use of the room.
In a very rough calculation these are the values:
Owners cabin and guest cabins: K = 15
Saloon or dinette without or limited window and glass area (sail yacht or power "open" configuration): K= 28-30
Saloon or dinette with large glass area (power boat- Fly configuration): K=35
Wheelhouse (power boat) with very large glass area: K=40

The "K" factor utakes into account the location of the cabin with respect to the anticipated heat load. Cross reference the cabin area (in square metres) to the K-factor to determine the BTU capacity required to cool the cabin. This formula uses a differential temperature (Outside air temperature minus inside temperature) of 15 degrees which is a standard for tropical climates.
K = 15 Owners cabin and guest cabins:
K= 30 Saloon/dinette/galley without or limited window and glass area (sail yacht or power "open" configuration):
K=35 Saloon or dinette with large glass area (power boat- Fly configuration):
K=40 Wheelhouse (power boat) with very large glass area

Apart of the above you can make modifications to the lighting to make the operation of the A/C more efficient, for example on board of our Yacht (which is currently under construction) we use only RGB LED lighting, thus the emissitive heat is extremely low and on the other hand we managed to reduce the consumption of 220V and 24V.

Hi,

You have obviously done your homework here Nomad.

Is this a new boat or a modification of an existing one?

I say this because you say in your first post that you have a semi custom boat under construction which to me means it's brand new being built.

Later on you have notes which you checked to get the actual fuel consumption which is based on Sea Trial data.

Is this info from the boat you have or a sister ship?

If it is not your boat that was Sea Trialled did the boat that provided you the figures have the same load as the one you are having done?

On the safety issue:

If you are really going to go to remote locations fishing you will pretty much be on your own.

Do you have any type of fixed fire fighting system onboard?

AIS whilst being ok to identify you is not the same as a Satellite EPIRB, you should also make sure you rafts have SARTS in them to assist any searching aircraft.

Another thing you should do is instigate a good fuel husbandry routine. You should use a good quality biocide to stop the growth of fungus in your fuel and if space allows I would suggest a filter setup that allows you to run with at least one in reserve like a triple Racor system where you can run on two and save the third one. If you need to change them you can keep the engine running and do them one at a time. This is especially handy if you are close to land and the sea is rough, this is a common time for fuel blockage problems as the remnants of the fuel slosh about in the tanks and wash all the mud down to the bottom and is a good time to not lose your power.

If as I imagine with a boat like this you will be running Low Sulphur Diesel you should also consider the use of a Fuel conditioning additive that stops the reported problems that are now appearing in the marine press with the prolonged use of ultra low sulphur fuels.

Here is an extract from *************.com, I didn't post it all as it becomes an Advert for a certain brand of fuel very quickly.

Due to EPA regulations, many marinas are required to sell low sulfur diesel as of October 1, 2007. Even in areas where high sulfur diesel can legally be sold, only low sulfur or ultra-low sulfur diesel may be available. Although low sulfur and ultra-low sulfur diesel help to reduce harmful exhaust emissions, they can also cause damage to marine diesel engines. They destabilize much faster, have poor lubricity, contain more moisture and are more susceptible to bacteria growth than traditional high sulfur diesel fuel.

It would also be prudent to have some advanced first aid training for yourself at least and anyone else who will be with you regularly onboard.

I don't want to sound or read like the prophet of doom here but there is a lot to be considered when cruising outside the normal regions where help and assistance is always at hand.

Please keep us posted as to how your adventure progresses, if as your user profile indicates are on the West Coast you are not that far from some seriously good fishing so the tales of big ones should be soon to appear

Rick, it seems to me you'll need two 10-man life rafts. Make sure they can float free and deploy automatically with a hydrostatic release.

Good luck with your project,

Bruno

Sounds like an fun project. I am in the process of spec-ing out a semi-custom build as well, for the same intended crusing areas (Alaska to Panama), except there won't be as heavy emphasis on fishing.

In addition to what you have heard, I would focus on the system details like redundancy. There are simple things, like having a redundant fresh water pump, that can make the difference between a great trip and a problematic one. I am going to the extent of having a separate battery and charger for my primary radio (bridgeable to the house batteries), this is really cheap insurance.

Another couple of examples include: the electrical panel and electrical system layout; size of sea strainers in the engine room; water tightness of the doors and hatches; and fire fighting system as someone mentioned above.

Lastly, given that kind of cruising, I would also have an isolation transformer and voltage booster.

the unit is square meters, below is an example calculation for our Yacht which is currently building:

Main Saloon (30.10 m2) => Heat Load= 30.10 x (10) x K(35)= 10,535 W/h x 3.4= 35,819 BTU/h

S=The floor area of the room to be conditioned.
Te= External temperature
Ti= Desired Inside temperature
K=Thermal coefficient of the room to be conditioned (there must be a K, otherwise what formula is this?)
The formula is: Heat load = S x (Te-Ti) x K.
(Te - Ti) depends from the climate somebody has to consider: Mediterranean uses officially 8-10 which is the difference somebody wants to achieve between outside and inside temperature. For tropical climates the standard used value is 15.