Help designing shallow deep police aeroboat

I found this, Jerry said it better than I was able to.

From: Jerry
To: HoverLovers@yahoogroups.com
Sent: Sunday, June 19, 2005 10:49 PM
Subject: Re: [HoverLovers] FINGER VERSES BAG SKIRTS (mike)

The bag/finger skirt offers a compromise between the two. Less stable than a standard bag skirt, but more stable then a standard finger skirt. Easier maintenance as I believe, the fingers are replaced rather than the skirt, so the bag get little wear on it.

A bag skirt has better stability and less sensitive to balance and weight shift, although it does effect it, but not like a finger skirt. Bags are easier to make and less expensive. The ride isn't as smooth as a finger skirt. Repairs between a bag and finger skirt are a matter of opinion. Fingers are just replaced. A bag has to be patched, but in the field, a hole punch and a few wire ties make a very quick repair and get you back on cushion and moving again. The bag will wear faster on rough surfaces so mainly used for water use.

Finger skirts conform to terrain better. Offer a smoother ride and wear better on rough surfaces. But "generally" require higher hp engines as all the lift air goes into the fingers and exits under the craft. So a high reving single engine with about 1/3 to 1/4 of the air into the plenum to feed the skirts, or a separate engine (i.e. Air Commander) but they use I think, a 20 hp 2 cycle for lift where a similar size bag skirted craft would use 8 hp or less for lift.

The bag/finger combo is usually much harder for the home builder to make. That's why we don't see many of them on recreational craft.

As Michael said, if the primary use is water, go with a bag. If it's a 50/50 water-land craft, or more land than water, a finger skirt would work better for you. It's all a matter of what you want the craft to do and what it's primary use is or will be.

Jerry

 

Combinations work well. Bag/finger may be best.

 

FYI:
Big hovercraft event in southern Ohio this weekend, just south of Columbus in Chillicothe.

http://www.hoverclubofamerica.org/

 

Well,

I have 25 years of experience constructing composite “one off” sail multihulls, but I must confess I do not have any know how about finger skirt.
There is one thing that I’d like you to figure out: we have to think about a tough boat, but it must be light too otherwise we wont be able to navigate in shallow deep waters.
I’ll ask you to excuse me but couldn’t talk to the one that will define all the boat parameters (such as number of passengers) so by now I can only speculate about that boat.

Thank you very much

Ricardo Aurelio

 

Steel or aluminium are both very strong materials and, overall, are pretty light.

 

Aluminium I think is lighter and cheaper in most applications than exotics like Carbon Fiber/Kevlar which needs to be baked in an autoclave to reach full strength.

If cost was no object then I would still have to look at the corrisive affects of salt water on Carbon Fiber/Kevlar.

How does Aluminium do in salt water? What spec/quality do you need to purchase? What kind of paint if any to protect it?

This is way out of my area of speculation but I'm interested in learning all I can.

Go for it.

 

Honestly, I have no idea about marine quality metals nor about paints. All I really know is that they are used in many vessels and were used for PBR (Patrol Boat, River) or "pibbers" (riverine patrol craft, nice and strong) in Vietnam. These vessels, along with many other metal-watercraft have been proven extremely sucessful, in addition to being stronger than fiberglass.

 

Well, I finally got all the information about the boat our local Environment Police need. I was wrong thinking their needs should be shallow deep boat. They already have a hovercraft and a small powerboat for that purpose.
It must be an offshore boat capable of carrying 6 policeman plus some extra loads as prisoners and arrested merchandise.
The boat should have a small stem platform or deck to aloud the police to easily enter into other boats.
I believe a central piloting “house” should be a good idea.
Do you have any suggestion?
Thank you for your help.

Ricardo Aurelio

 

Probably a rigid hull inflatable. Look at protector boats. (Protectorboats.com) Or, perhaps, Maritime Skiff (Not a RIB though) maritimeskiff.com

 

1. I gave a link which listed "Boston Whaler" and similar boats used in police work all over the world - please look at it again. The Boston might be exactly what you are looking for. They have a good website too.

2. They still have a hovercraft! Happy days, I love hearing that. Any chance of getting additional information on it, it's spec's, how it's used and pictures?

 

Thank you all for your help.
I'll let you know the "work" development.

Ricardo Aurélio

 

Cyclops is on my team at recess...

Hello...

That was funny and to the point - always good to cut the mustard...

SH.

 

I'm not that fond of mustard, a little more garnish is welcomed.

 

Rigid hull inflatables are perfect.